# Does the sun itself present the problem of global warming is it the main cause?

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the sun itself is not responsible for global warming, it must be that the temperature is changing due to climate changes. Anyone?

The energy input of the Sun stays constant (mostly, there are some minor variations), so no, the Sun is not responsible for climate changes.

The temperature of the Earth has to do with the balance between the energy input, and the energy radiated back into space. If the temperature is not changing, they are the same. Global warming is caused by gasses in the atmosphere limiting the energy radiated into space, therefore, the temperature rises, until the energy radiated is again equal to the solar energy input.

Actually the sun's output over time does vary, and it does cause climate changes. There is an 11 year cycle as shown in this image from www.sciencemuseum.org.uk:

And in the early half of the 20th century it did increase slightly, which probably did contribute to global warming during that time but over the last 50 years it has actually slightly cooled, so it is absolutely not responsible for the global warming we currently see. This image (from the same source) shows some nice detail. The dotted line is the moving average:

## Does the sun itself present the problem of global warming is it the main cause? - Astronomy

“You Asked” is a series where Earth Institute experts tackle reader questions on science and sustainability. Over the past few years, we’ve received a lot of questions about carbon dioxide — how it traps heat, how it can have such a big effect if it only makes up a tiny percentage of the atmosphere, and more. With the help of Jason Smerdon, a climate scientist at Columbia University’s Lamont-Doherty Earth Observatory, we answer several of those questions here.

### How does carbon dioxide trap heat?

You’ve probably already read that carbon dioxide and other greenhouse gases act like a blanket or a cap, trapping some of the heat that Earth might have otherwise radiated out into space. That’s the simple answer. But how exactly do certain molecules trap heat? The answer there requires diving into physics and chemistry.

Simplified diagram showing how Earth transforms sunlight into infrared energy. Greenhouse gases like carbon dioxide and methane absorb the infrared energy, re-emitting some of it back toward Earth and some of it out into space. Credit: A loose necktie on Wikimedia Commons

When sunlight reaches Earth, the surface absorbs some of the light’s energy and reradiates it as infrared waves, which we feel as heat. (Hold your hand over a dark rock on a warm sunny day and you can feel this phenomenon for yourself.) These infrared waves travel up into the atmosphere and will escape back into space if unimpeded.

Oxygen and nitrogen don’t interfere with infrared waves in the atmosphere. That’s because molecules are picky about the range of wavelengths that they interact with, Smerdon explained. For example, oxygen and nitrogen absorb energy that has tightly packed wavelengths of around 200 nanometers or less, whereas infrared energy travels at wider and lazier wavelengths of 700 to 1,000,000 nanometers. Those ranges don’t overlap, so to oxygen and nitrogen, it’s as if the infrared waves don’t even exist they let the waves (and heat) pass freely through the atmosphere.

A diagram showing the wavelengths of different types of energy. Energy from the Sun reaches Earth as mostly visible light. Earth reradiates that energy as infrared energy, which has a longer, slower wavelength. Whereas oxygen and nitrogen do not respond to infrared waves, greenhouse gases do. Credit: NASA

With CO2 and other greenhouse gases, it’s different. Carbon dioxide, for example, absorbs energy at a variety of wavelengths between 2,000 and 15,000 nanometers — a range that overlaps with that of infrared energy. As CO2 soaks up this infrared energy, it vibrates and re-emits the infrared energy back in all directions. About half of that energy goes out into space, and about half of it returns to Earth as heat, contributing to the ‘greenhouse effect.’

By measuring the wavelengths of infrared radiation that reaches the surface, scientists know that carbon dioxide, ozone, and methane are significantly contributing to rising global temperatures. Credit: Evans 2006 via Skeptical Science

Smerdon says that the reason why some molecules absorb infrared waves and some don’t “depends on their geometry and their composition.” He explained that oxygen and nitrogen molecules are simple — they’re each made up of only two atoms of the same element — which narrows their movements and the variety of wavelengths they can interact with. But greenhouse gases like CO2 and methane are made up of three or more atoms, which gives them a larger variety of ways to stretch and bend and twist. That means they can absorb a wider range of wavelengths — including infrared waves.

### How can I see for myself that CO2 absorbs heat?

As an experiment that can be done in the home or the classroom, Smerdon recommends filling one soda bottle with CO2 (perhaps from a soda machine) and filling a second bottle with ambient air. “If you expose them both to a heat lamp, the CO2 bottle will warm up much more than the bottle with just ambient air,” he says. He recommends checking the bottle temperatures with a no-touch infrared thermometer. You’ll also want to make sure that you use the same style of bottle for each, and that both bottles receive the same amount of light from the lamp. Here’s a video of a similar experiment:

A more logistically challenging experiment that Smerdon recommends involves putting an infrared camera and a candle at opposite ends of a closed tube. When the tube is filled with ambient air, the camera picks up the infrared heat from the candle clearly. But once the tube is filled with carbon dioxide, the infrared image of the flame disappears, because the CO2 in the tube absorbs and scatters the heat from the candle in all directions, and therefore blurs out the image of the candle. There are several videos of the experiment online, including this one:

### Why does carbon dioxide let heat in, but not out?

Energy enters our atmosphere as visible light, whereas it tries to leave as infrared energy. In other words, “energy coming into our planet from the Sun arrives as one currency, and it leaves in another,” said Smerdon.

CO2 molecules don’t really interact with sunlight’s wavelengths. Only after the Earth absorbs sunlight and reemits the energy as infrared waves can the CO2 and other greenhouse gases absorb the energy.

### How can CO2 trap so much heat if it only makes up 0.04% of the atmosphere? Aren’t the molecules spaced too far apart?

Before humans began burning fossil fuels, naturally occurring greenhouse gases helped to make Earth’s climate habitable. Without them, the planet’s average temperature would be below freezing. So we know that even very low, natural levels of carbon dioxide and other greenhouse gases can make a huge difference in Earth’s climate.

Today, CO2 levels are higher than they have been in at least 3 million years. And although they still account for only 0.04% of the atmosphere, that still adds up to billions upon billions of tons of heat-trapping gas. For example, in 2019 alone, humans dumped 36.44 billion tonnes of CO2 into the atmosphere, where it will linger for hundreds of years. So there are plenty of CO2 molecules to provide a heat-trapping blanket across the entire atmosphere.

In addition, “trace amounts of a substance can have a large impact on a system,” explains Smerdon. Borrowing an analogy from Penn State meteorology professor David Titley, Smerdon said that “If someone my size drinks two beers, my blood alcohol content will be about 0.04 percent. That is right when the human body starts to feel the effects of alcohol.” Commercial drivers with a blood alcohol content of 0.04% can be convicted for driving under the influence.

“Similarly, it doesn’t take that much cyanide to poison a person,” adds Smerdon. “It has to do with how that specific substance interacts with the larger system and what it does to influence that system.”

In the case of greenhouse gases, the planet’s temperature is a balance between how much energy comes in versus how much energy goes out. Ultimately, any increase in the amount of heat-trapping means that the Earth’s surface gets hotter. (For a more advanced discussion of the thermodynamics involved, check out this NASA page.)

### If there’s more water than CO2 in the atmosphere, how do we know that water isn’t to blame for climate change?

Water is indeed a greenhouse gas. It absorbs and re-emits infrared radiation, and thus makes the planet warmer. However, Smerdon says the amount of water vapor in the atmosphere is a consequence of warming rather than a driving force, because warmer air holds more water.

“We know this on a seasonal level,” he explains. “It’s generally drier in the winter when our local atmosphere is colder, and it’s more humid in the summer when it’s warmer.”

As carbon dioxide and other greenhouse gases heat up the planet, more water evaporates into the atmosphere, which in turn raises the temperature further. However, a hypothetical villain would not be able to exacerbate climate change by trying to pump more water vapor into the atmosphere, says Smerdon. “It would all rain out because temperature determines how much moisture can actually be held by the atmosphere.”

Similarly, it makes no sense to try to remove water vapor from the atmosphere, because natural, temperature-driven evaporation from plants and bodies of water would immediately replace it. To reduce water vapor in the atmosphere, we must lower global temperatures by reducing other greenhouse gases.

### If Venus has an atmosphere that’s 95% CO2, shouldn’t it be a lot hotter than Earth?

Thick clouds of sulfuric acid surround Venus and prevent 75% of sunlight from reaching the planet’s surface. Without these clouds, Venus would be even hotter than it already is. Credit: NASA

The concentration of CO2 in Venus’ atmosphere is about 2,400 times higher than that of Earth. Yet the average temperature of Venus is only about 15 times higher. What gives?

Interestingly enough, part of the answer has to do with water vapor. According to Smerdon, scientists think that long ago, Venus experienced a runaway greenhouse effect that boiled away almost all of the planet’s water — and water vapor, remember, is also a heat-trapping gas.

“It doesn’t have water vapor in its atmosphere, which is an important factor,” says Smerdon. “And then the other important factor is Venus has all these crazy sulfuric acid clouds.”

High up in Venus’ atmosphere, he explained, clouds of sulfuric acid block about 75% of incoming sunlight. That means the vast majority of sunlight never gets a chance to reach the planet’s surface, return to the atmosphere as infrared energy, and get trapped by all that CO2 in the atmosphere.

### Won’t the plants, ocean, and soil just absorb all the excess CO2?

Eventually … in several thousand years or so.

Plants, the oceans, and soil are natural carbon sinks — they remove some carbon dioxide from the atmosphere and store it underground, underwater, or in roots and tree trunks. Without human activity, the vast amounts of carbon in coal, oil, and natural gas deposits would have remained stored underground and mostly separate from the rest of the carbon cycle. But by burning these fossil fuels, humans are adding a lot more carbon into the atmosphere and ocean, and the carbon sinks don’t work fast enough to clean up our mess.

A simplified diagram showing the carbon cycle. Credit: Jack Cook/Woods Hole Oceanographic Institution

It’s like watering your garden with a firehose. Even though plants absorb water, they can only do so at a set rate, and if you keep running the firehose, your yard is going to flood. Currently our atmosphere and ocean are flooded with CO2, and we can see that the carbon sinks can’t keep up because the concentrations of CO2 in the atmosphere and oceans are rising quickly.

The amount of carbon dioxide in the atmosphere (raspberry line) has increased along with human emissions (blue line) since the start of the Industrial Revolution in 1750. Credit: NOAA Climate.gov

Unfortunately, we don’t have thousands of years to wait for nature to absorb the flood of CO2. By then, billions of people would have suffered and died from the impacts of climate change there would be mass extinctions, and our beautiful planet would become unrecognizable. We can avoid much of that damage and suffering through a combination of decarbonizing our energy supply, pulling CO2 out the atmosphere, and developing more sustainable ways of thriving.

Editor’s note (March 17, 2021): This post was updated with additional links to Youtube videos with experiments showing the effects of carbon dioxide. Enjoy!

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I’m writing a paper for my environmental class How does the cooler atmosphere transport heat Q to the warmer surface?
Q = sigma•(Ts^4 -Ta^4)

If the air’s cooler than the surface, it wouldn’t.

It doesn’t. Heat always flows from higher temperature to lower temperature.
If it didn’t, the 2nd Law of Thermodynamics would be violated, and entropy would decrease (as enthalpy increased).

The “greenhouse gas” mechanism does not exist. The atmosphere (including CO2) provides convection cooling to the Earth’s surface. Cloud cover does *temporarily* prevent radiational cooling by reflecting radiation back to the surface. This is distinctly different than the fictitious greenhouse gas model of absorption-and-reemission. The atmosphere also distributes heat more evenly around the planet through convection heat transfer in general this is why the planet surface doesn’t have wild temperature differences from day to night like the moon. There is NO net warming effect due to so-called greenhouse gases.

That being said, here’s what I’m NOT saying:

-I’m not saying global warming isn’t real. We are experiencing a warming trend.
-I’m not saying human activity doesn’t add to this warming trend it does.
-I’m not saying trying to minimize environmental impact isn’t worthwhile. It is not only worthwhile, it is critical.
-I’m not saying plants and trees do not have a net cooling effect. They do, but it is because they are endothermic from a heat balance point of view. Plants are great because they absorb energy, NOT because they happen to use CO2 to do this.

All I’m saying is that if anyone is concerned about reducing anthropogenic global warming effects, the best approach is to try to minimize waste heat.

7.5 billion humans generate a LOT of waste heat. Birth control and insulation will help. Sequestering plant food (CO2) will make the problem worse.
Less CO2=less plant life=less radiant energy from the sun being used during photosynthesis.

The obvious retort here is that many actions essential if mainstream theories are correct make sense regardless of the nature, extent, cause and direction if climate change. They would help cope with a volcanic winter (e.g. that in 1816 after the Tambora eruption) and also the collapse of a major food crop. Examples include less waste, combining conservation with careful use, restoring fish stocks, growing fewer cash crops, regenerative agriculture, silviculture and reducing the impact per head and probably numbers of conventional livestock.. Instead of shovelling grain and soya down cattle they can be fed on crop residues, natural vegetation and spent brewery grain while methane-reducing feed additives like Asparogopsis taxiformis in livestock feed could give a huge cut in emissions and some boost growth.

These are all win-win options which make sense regardless. Instead of adopting them, humanity has wasted decades bickering about who is right. I despair at times!

I posted something on food security on the climate coalition website last year if you’re interested.

The greenhouse gas mechanism definitely does exist. Colder objects still radiate, unless they are at absolute zero. The atmosphere is well above that at 255 K or so on average, and it radiates plenty of infrared light. When that infrared light strikes the ground, what do you think happens?

The best, most complete and correct answer below is from Lisa Goddard. I will simplify it even further by saying there are only two forms of heat transfer – conduction and radiation. Convection is a special case of conduction in which fluid flow (air in this case) is taken into account as a heat distribution mechanism, and influencer of heat transfer coefficients (I got an A- in my first semester of heat transfer), but ultimately it is still conduction.

Conduction occurs with the molecules or atoms of a substance come into contact and transfer energy to one another. So it is fair to say there will not be a net transfer of thermal energy (heat) from cooler air to a warmer surface through conduction.

The other mechanism of heat flow is radiation. This is the radiation of electromagnetic radiation from objects, ie the molecules and atoms in bodies. This form of energy can travel through a vacuum, such as the various forms of electromagnetic radiation that travel through the vacuum of space to our Earth. After absorbing this radiation from the sun, the earth’s surface radiates some of it back into space in the form of infrared radiation which has a little bit longer wave length than the various visible light wavelengths we see. Oxygen and Nitrogen in the air mostly ignore it, but Carbon Dioxide molecules have the geometry and composition that allows them to absorb the radiation of this wavelength. They get “excited” and re-radiate the energy, again as infrared, back out. Some goes up, and some goes back down to the surface.

So if there was only O2 and N2 in the atmosphere the infrared energy would mostly radiate back into the black body of space. But each CO2 molecule catches some and sends a portion back to earth. The more CO2 molecules there are, the more infrared radiation gets interrupted and sent back to earth, instead of out to space. That is how CO2 in the atmosphere can transfer energy to the surface, by blocking infrared energy heading to space and sending some of it back to the surface.

Overall, increasing CO2 and other greenhouse gasses reduces the earth’s ability to “cool itself off” by radiating energy into space. In other words the greenhouse gas molecules “catch” the infrared energy trying to escape earth, and “throw” some of it back to earth. Increasing greenhouse molecules, increases the amount of energy that gets caught and sent back.

In your final sentence you say that radiation increases greenhouse molecules. Energy converts to matter. That sounds faintly ridiculous. It would be useful to read an explanation of how that works.

There are 3 ways that energy can be transferred: conduction, convection, and radiation. What John LK and Daniel H have described are 2 of those, and both are certainly at play in distributing the sun’s energy that the surface (and some atmospheric constituents) absorb. What they both have not addressed is radiation. This is how greenhouse gasses work in our atmosphere, and incidentally, how the sun’s energy reaches Earth. If there were no greenhouse gasses in the atmosphere, heat energy radiated from the surface would almost entirely radiate back to space, leaving the surface at a very very cold -18C (or about 0F, and that is averaged over the whole planet surface!). Greenhouse gasses (like CO2 and water vapor) can effectively absorb the wavelengths associated with what we call “heat”, or infrared radiation, coming from the surface or other parts of the atmosphere. They will re-radiate that energy in all directions, sending energy back to the surface, as well as out to space. This is how the surface is effectively receiving additional energy (and thus can warm). Those greenhouse gas molecules will radiate at the temperature of their immediate environment. So, CO2 or H2O near the surface radiate at a higher temperature than those same molecules higher up in the atmosphere. The altitude, above which there are no more appreciable greenhouse gasses will appear to be the radiating temperature at that point (often called outgoing long wave radiation).
@Joe — in your equation below, this would be an expression for the energy balance at the surface, used to determine either the temperature of the surface or of the atmosphere, in a very idealized context, where the atmosphere is one big slab of stuff. What you are missing there though, is an ‘epsilon’ that represents the opacity of the atmosphere, basically the ability to absorb/emit radiation. The Q in that equation would be the net energy received from the sun, which is known and become approximate in the specific value for the Earth’s albedo (how much sun is reflected back to space). If you add one more equation – say the energy balance within the atmosphere, or at the top of the atmosphere, you would have enough information to solve for one, say T_surface, and find the other (T_atmosphere — though again, this would be an idealized representative temperature for the entire atmospheric column over the planet, but that is a similar situation for the surface temperature in this case too).

The intelligent and accurate retort as opposed to my less intellectual bypassing the whole argument – see previous post.

I’m after the physics describing the greenhouse effect/mechanism of heat transfer.

The equation is a radiative heat transfer equation the units are expressed in power per unit area, not energy. To get energy integrate power per unit area over time then multiply by area

The equation is for heat transfer between two surfaces, earth and the atmosphere.

Suppose the sun is delivering power to the surface over time transferring energy
generating surface temperature Ts.

In my paper I’m after the physics describing the greenhouse effect/mechanism of heat transfer.

The equation used is a radiative heat transfer equation applied between two surfaces, earth and the atmosphere. The equation has units of power not energy. For simplicity epsilon is 1.

Applying the equation to a single layer atmospheric model we know heat from the sun (Qs), and can find atmosphere temperature (Ta), earth surface temperature (Ts)……

The term “back radiation” is used to describe the heat transfer mechanism. Using the radiative heat transfer equation and applying it to a single layer model with the known values for Ts & Ta

When is Q negative for atmosphere to surface heat transfer?

Your equation is set up to always give the answer that the atmosphere can’t warm the surface, which is wrong. You need to compare the situation with a warm atmosphere to one with no atmosphere at all.

For the present situation, Ts = 288, Ta = 255, so Q = 5.670373e-8 (288^4 – 255^4) = 150 W m^-2.

Now try Ts = 288, Ta = 2.7 K (the temperature of interstellar space). You get Q = 390 W m^-2.

In other words, with the warm atmosphere there, net radiation leaving the surface is 150 W m^-2, but without the atmosphere in the way, it would be 390 W m^-2. Input and output would no longer balance and the Earth would cool off until it was radiating as much as comes in. (This whole discussion ignores sunlight, convection, and evapotranspiration, which are necessary to give a proper balance.)

Many, many universities and others will have attempted to prove the Greenhouse Effect in a lab. However, nobody has published a single paper demonstrating heating from such a mechanism. The rewards for demonstrating the GHE are multiple Nobel Prizes for everyone involved – probably even including the president of the country.
Worse still, not one publication has been seen covering failed experiments or null results. That is just dishonest surely. Null results are extremely important in science – otherwise it just becomes Groupthink.

If 97 to 98% of the co2 in the atmosphere comes from natural sources how much impact can industrial sources have based on the small % of co2 in air. Isn’t it true that during the jurrasic period co2 levels were 10 times what they are today. Seems to me like a futile effort, nature rules in this case.

The atmosphere is not 2-3% artificial CO2 but 33% artificial CO2. You are confusing the fraction of emissions with the fraction of build-up. All the natural sources are matched by natural SINKS. The artificial production is not, so that’s where the increase comes from.

yes, remove all the CO2, and all the plants die, and the human race is not far behind. you can kiss your ass goodbye if all the plants die.

No one is saying we should remove all the CO2. It’s about returning CO2 to reasonable levels.

CO2 is at the Optimal level right now

Yeah I guess if you like extra droughts and wildfires and deadlier hurricanes? Not my idea of optimal.

What is a reasonable level in ppm.?

Climate scientist James Hansen has suggested that we should try to limit CO2 to 350ppm, although for thousands of years, natural cycles didn’t bring it above 300ppm: https://climate.nasa.gov/vital-signs/carbon-dioxide/

All human civilization and agriculture developed when the CO2 level was about 280 ppmv and the (mean global annual surface) temperature was 286-287 K. Serious deviations from that either way have the potential to badly disrupt our agriculture and our civilization.

So, what is your opinion of what a “reasonable level” of CO₂ is? Do you think that during the Ordovician period when the CO₂ level was at 2,240 ppm and the Earth survived that was a “reasonable level”?

Yeah, the Earth has survived a lot of things. For millions of years, the surface of the planet was molten from being struck by so many asteroids and other space debris, and the Earth survived. So I guess it’s ok to return to those conditions, too? Just because the Earth has survived hell, doesn’t necessarily mean the human species can or will. Climate change is already causing a lot of human suffering, and it could get worse if we let it — does that just not matter to you? Do the profits of fossil fuel companies matter more than human lives?

Even if we get to net zero, we still need to get carbon dioxide out of the atmosphere,’

‘This is a bigger challenge than a lot of people have really grabbed on to yet.’

But how can we remove it from from the atmosphere yet daily industries are evolving

I am strugling to find a percentage, or range of percentages showing the proven human activity responsible for the global warming. This is a question I get stumped with by sceptics. Is there unquestionable data and science to support that, say, 70% to say 90% of the increase in temperature is proven to be a result of human activity? While CO2 modelling I appreciate is complex, does the science (at a molecular modelled level) show without question that the increase in CO2 in our atmosphere causes the associated increase in termperature we measure. While I can see the data graphs that imply this, is there detailed modelling that supports this? I am working with the IMechE to have a supportive presence at COP26 and, while I just want to clean up our planet regardless, I need good back up when I field questions from sceptics.

The obvious retort to sceptics is that many ideas essential if mainstream views are correct make sense even if climate change were a damp squib or temperatures fell e.g following a major volcanic eruption like Tambora in 1815. For that matter they work if a major food crop collapses. Typical actions include reducing waste, silviculture, regenerative agriculture, alternatives to fossil fuels (whose extraction can be polluting or destructive), fewer cash crops, combining conservation with careful use and cutting the impact per head and probably numbers of conventional livestock. These win-win options are effective no matter what. Instead the last few decades have seen huge debate on climate change rather than doing something effective to cover all bases.

All the recent warming can be attributed to human activity. If you add up all the natural forcings, the Earth should be slowly cooling. It’s only when you add the artificial ones that you get warming.

I have some question, When the sunlight hit the ground it transforms into infrared light, when the infrared light hit the CO2, shouldn’t the wavelength changed too?

My understanding is that when sunlight hits the ground, it heats the ground. Because the surface of the sun is so hot, the radiation is mainly in the visual, i.e. at relatively short wavelengths. The ground is radiating back, but because the ground is so much less hot, it radiates at longer wavelengths, i.e. in infrared. The sunlight is not transformed directly. It is the net result of absorption and emission by the ground. If CO2 is then heated by infrared radiation, and the temperature is not much different, it should re-emit the radiation in about the same wavelength.

So does Co2 absorb and emit radiation or does it block it ?
The article talks about radiating, but the experiment you show seems to show blocking. Shouldn’t we see the Co2 absorb the heat and re radiate it ? Of course the experiment is faked anyway. That is a laboratory FLIR. Camera. It can show temperatures in at least 4000 colors . But the only thing it shows at all is the candle flame. Therefore the sensitivity on the expensive FLIR camera is cranked down so low it only registers if something is on fire. Then he fills the chamber with gas from a cylinder. That comes out very cold. The carbon dioxide which is cold, would have to be on fire to register on the misadjusted FLIR cam, and so effectively blocks the flame like a cold smoke screen. Then he cuts it short. I’m sorry, that is fakery to fool children.

The CO2 scatters the infrared by absorbing it and reemitting in all directions — which is exactly what the video claims to show. Since some of the infrared is bounced back to the source, it is often characterized as “blocking.”

But it doesn’t show that at all. It only shows that the cold gas blocks infrared for few seconds, to a badly adjusted FLIR camera.

Unfortunately, neither you nor I know the exact conditions of the experiment and what temperature the CO2 gas was at. However, climate scientist Jason Smerdon says that even if the gas was cold, the IR from the candle would still transmit directly to the camera if the gas were not interacting with the IR radiation. So, the experiment shows that the CO2 is scattering the IR, regardless of the gas’s temperature.

It’s also worth noting that even if there were a problem with the experiment, scientists know from many other lines of evidence that CO2 absorbs and scatters infrared energy — that fact of nature does not hinge on this one Youtube video.

Hi James, here’s a slightly experiment where cold CO2 is definitely not an issue, and it shows the same results: https://youtu.be/Rt6gLt6G5Kc?t=107 Hope this helps

If Mars is 95%co2 how come it is not hotter. My last question is what happened to the sunspots. Did the industrial revolution cause that too?

Most of Earth’s greenhouse effect comes from water vapor and clouds, which together account for about 25 K of the Earth’s 33 K difference from the radiative equilibrium temperature (CO2 accounts for most of the rest). Mars has a very dry atmosphere. In addition, its atmospheric pressure is very low, so the absorption lines are not pressure-broadened the way they are on Earth, and the greenhouse effect is less effective. Lastly, Mars receives much less sunlight than Earth. Despite all this, Mars does wind up with a greenhouse effect of about 4 K (radiative equilibrium temperature is 210, emission temperature is 214).

Indeed the climate is changing and CO2 certainly seems to be playing a role. However, I find the statement “Unfortunately, we don’t have thousands of years to wait for nature to absorb the flood of CO2. By then, billions of people would have suffered and died from the impacts of climate change there would be mass extinctions, and our beautiful planet would become unrecognizable” to be coming out of thin air. The climate has changed in human history (medieval warm period, ice ages) and humans have always been able to adapt. Why would this climate change be different? “Billions dead” ? Why?

Droughts, wildfires, extreme heat, hurricanes, sea level rise, infectious disease — climate change makes all of these things worse, and the climate is changing faster and more dramatically than in all of human history. Surely we can and will adapt, and a big part of adapting means moving away from fossil fuels.

Recently, I became embroiled in an online debate on the subject of anthropogenic global warming (“Claim”) originated by a talk radio host, who was hostile to the claim of anthropogenic global warming. Some responders were outright abusive, but one at least posed the following counter-arguments to the Claim:

(1) “So one of you educated climate alarmists please the explanation of how CO2 in the atmosphere is capable of increasing its fingerprint absorption wavelengths of 2.7, 4.3, and 15 microns so that it can absorb more than 8% of the infrared spectrum that it already does” “Don’t give me the ‘broadens its wings’ explanation b/c that only accounts for about 1.7% increase when the CO2 is doubled” (explanation offered by the IPCC)

“Since the science is ‘settled’, you no doubt have that explanation handy and it will no doubt be in peer reviewed form”.

(2) “Explain while the dilution of the CO2 molecules by other molecules is ignored. Every [email protected] molecule in the atmosphere is, at current concentration, surrounded by 2500 other molecules. In order for CO2 to heat the atmosphere to just one degree, the CO2 molecule would have to start at a temperature of 2500 degrees C.

(3) “Also, explain why the climate scientists use the Stefan-Boltzmann constant incorrectly to explain radiation from the air to the ground. (The) Stefan-Boltzmann constant is how much radiation is given off an OPAQUE surface at a given temperature.”

This was actually the least contentious response. I was just wondering how anyone at Columbia would answer these counter-arguments.

I did read the article, which was very informative. I was informed by someone else that the Stefan-Boltzmann constant is not used in the more current, detailed models, which accounts for “Challenge” 3. Challenge 2 seems a bit absurd, and is a thermal transfer issue. The one that kind of confounded me was Challenge 1, an atmospheric chemistry issue. Would have something specific to say about this one, say if it was posed directly to you?

I would like to know what is the way that carbon dioxide involves global warming

If you see the earth as a ball receiving energy (from the sun) and emitting energy (infrared due to the earth’s temp), you may understand that in the long run , incoming and outgoing energies must be equal.exept for storage changes. So all outgoing energy is infrared.
From infrared spectroscopy we know some gases absorb infrared energy in the infrared area. CO2 is one of them as is H2O vapour.
Gasses like CO2 do not only absorb infrared radiation, but they also re-emit the same radiation, , this time in whathever direction, partly back to the earth.
If you would measure the infrared output of the earth at sealevel and you would measure this outside the atmosphere, you would find a difference.
in certain bands, much less infrared energy leaves the earth. If this energy does not leave the earth, it can only heat it. Wenn the temperature of the earth rises a little bit, the earth starts emitting more infrared energy, so balancing again, at a sligtly higher temp.

Hi I was wondering how does carbon dioxide have a big impact on global warming. I was just wondering for a school project.

I find many of these answers far too simplistic and not nearly quantitative enough to satisfy my curiosity.

I note that the insulation response involves elements of convective resistance, conductive resistance and radiative resistance. In all cases it is a logarithmic function and not linear. Why no mention of any of these factors when it comes to CO2? Doesnt each doubling of CO2 halve its already minuscule IR absorption factor? If so shouldn’t you point this out so your followers are not unduly alarmed

I also note that the hottest areas on Earth are found in dry, below-sea-level valleys located in temperate zones. This correlation appears to have nothing to do with CO2 concentrations. The hottest official temperature that ever occurred on Earth occurred at Greenland Ranch in Death Valley in 1913 long before the heavy use of fossil fuels were in effect. How can this be? Are we cherry picking only the factoids that support our preferred premise?

My own idea is that moist air carries far more thermal inertia than dry air and yet the two are treated identically by using simple average temperature. Aren’t joules/mass the appropriate metric for the effect of heat trapping gases?

Further, how far must IR radiation travel before encountering a CO2 molecule that absorbs its energy at .04% concentration at standard temperature and pressure? Once absorbed doesn’t this energy lead to convective forces carrying the molecule into lower pressure zones at higher altitude before losing its energy to other cooler molecules. There are endless complexities to these energy transfers that I have never heard explained satisfactorily, other than with the typical simple bromides.

Moreover, more CO2 can’t simply mean increased oceanic evaporation because if that were true there would be runaway evaporation causing more greenhouse gases until the oceans boiled away. Clearly there can be no positive feedback associated with increased evaporation. I might suggest that cloud cover of all types have a great deal of influence over regulating radiation flux impinging on the surface. No mention of any of this – why?

Lastly your spectrum of greenhouse radiation chart (above) makes no mention whatsoever of water vapor with its broad spectrum of IR radiation absorption making it the only significant greenhouse gas and often completely masking the effects of any additional CO2 interference

If I understand you correctly, you want to adress 3 points.

What is the quantative relation between absorbtion and concentration for CO2?
Such issues are very well known in standard Chemical analysis, Any good chemistry book on spectroscopy can help you further.

The relation between amount of water vapour in the air and temperature.
You state correctly that dry area’s have the highest temperatures. This is very well known in all desert areas around the world. However, only at daytime, the nights are cold.
In general, very unevenly distributed water vapour levels, both by region as by height, makes understanding and calculating very difficult.
CO2 levels, which are, contrarely to water, evenly distributed around the world, have virtually no influence on local temp. differences.

Your third point: ,”” more CO2 can’t simply mean increased oceanic evaporation”” is incorrect. CO2 has an independent (its own) contribution to earths temperature and thus to oceanic evaporation.An associated positive feedback can be a moderate one, it does not automatically mean an explosive one.

The planet Mars has an atmosphere of 96% CO2 but a surface temperature of -62°C (-80°F) shouldn’t the planet be a bit warmer than this if CO2 traps heat even allowing for the thinner atmosphere and a further distance from the Sun that the Earth?

I just want the temperature to be 70 degrees F constantly, worldwide, how would I go about accomplishing that?

Impossible.
Suppose, it was 70 degrees worldwide, so emitting roughly equal amounts of IR radiation per square meter everywhere, where would that energy come from ?, the sun?, no way.
Impossible.

Why are most, if not all, of the UN’s IPCC temperature models over the past 20 years showing temperature increases much, much higher than what has actually happened? And that’s even with RSS temperature models cooling the past and warming the present more and more with every new model version? If the IPCC’s models can’t have at least an average error over and under actual temperatures, measured by a obviously biased-to-warmth RSS model set, then how can we ever believe the CO2 alarmist’s calls to action on climate change?

How Exactly Does Carbon Dioxide Cause Global Warming?
BY SARAH FECHT |FEBRUARY 25, 2021

The article notes that ‘Water is indeed a greenhouse gas (and) it absorbs and re-emits infrared radiation, and thus makes the planet warmer.’ The article also notes that ‘warmer air holds more water’
This appears to suggest an uncontrolled feedback loop where warmer air holds more water in turn making the planet warmer.
The article also notes that ‘temperature determines how much moisture can actually be held by the atmosphere.’ Again suggesting the possibility of an uncontrolled feedback loop.
Although most water drops out of the atmosphere as rain there is still significant volumes of water in air across the globe where the temperature is above the dew point.
These natural volumes of water in air appear to be significantly in excess of the volumes of CO2.
Indeed the volumes of water being injected into the upper atmosphere by aviation contrails have had the effect of increasing the level of atmospheric water through a mechanism that has not existed in the past.
Given that both CO2 and H2O are greenhouse gases the article does not seem to address how we can measure the relative influence of the two gasses.

The article addresses this issue. We can lower the amount of water in the atmosphere by lowering the temperature. We can lower the temperature by reducing carbon emissions.

Thank you for the prompt response and appreciate your feedback that we can lower the temperature by reducing carbon emissions. Given the clear evidence of global warming what is the scientific explanation for the way in which carbon emissions absorb more sunlight than water vapour.

I Think water vapour absorbs more, but 2 aspects might be considered.

1. water vapour can build clouds, reflecting sunlight so lowering energy input. a negative contribution.
2. CO2 is roughly evenly distributed around the world and relative to height, water vapour is not. Think of an extreme experiment in your mind. If all water vapour was concentrated in a narrow vertical cilinder and zero elsewhere, what would happen? Distribution matters.

The author seems to have forgotten that plants take up CO2. There will be better plant growth with more CO2. Insufficient CO2 will make a block to plant growth. There are more people on the planet, surely we need more plants to grow more food?

The author of this comment seems to have not read through to the end of the piece.

I want to propose a different perspective on the way we should looking.
Look only to energy in and energy out at the very outside of the worlds atmosfere.

Use minds experiment.
Use a world with a normal airshield, but without CO2.
We use long term stable temp., incoming energy (sun) and outgoing, let’s say at a 50 miles border outside the world( IR radiation), must be equal.

From spectroscopic data we read that outgoing energy is far less in the CO2 absorbtion window.

We started with incoming and outgoiing energies are equal in stable temp. conditions. As the sun is still the same and less energy is emitted in the greenhouse absorbtion bands, the temp starts raising untill the emitted IR once again , aquals thes sun’s

The earth can be considered what in physics is a black radiator. Its behavior can easily be calculated using a formula.

The rising temp. of the earth leads to more IR radiation, outside the greenhouse windows, leaving us forever.
Now we have a stable and equal situation again,
The energy not leaving the earth in the greenhouse windows equals the energy difference between the 2 black radiators is thus easily calculable.

A simplified way of calculating is:
1/ the energy blocked in the greenhouse gas window is expressed as a percentage of total IR radiation. example 5%
2/ the extra IR energy emitted by the black radiator (the earth) per degree temp raise is expressed in percentage of total IR emitted, example 2%.
Now the earths temp. raise is 2.5 %

sorry, 2.5 degrees of course

In the climate discussion the fate of excited CO2 molecules in the earth’s atmosphere has been ignored. The amount of CO2 in the atmosphere is widely believed to be responsible for global warming due to human activity. The IPCC explains the greenhouse effect in the atmosphere in their frequently asked questions as follows: “Much of the thermal radiation emitted by the land and ocean is absorbed by the atmosphere, including clouds, and re-radiated back to Earth. This is called the greenhouse effect.”
The mentioned greenhouse effect of CO2 is not in accordance with the molecular properties of CO2. These have to be treated quantum mechanically. The interaction with radiation as well as intermolecular interactions are described by quantum mechanics.
There are selection rules for possible energy transtions in molecules. Vibrational transitions are limited to molecules whose electric dipole varies during the vibration. This exclude homonuclear diatomic molecules such as O2 and N2 . For rotational transitions, the molecule must have a permanent electric dipole. This excludes homonuclear diatomics, with the exception of O2 which has a triplet electronic ground state allowing magnetic dipole rotational transitions. Therefore O2 is important in cooling the earth by emitting radiation from rotational states.
The radiative lifetime and collisional deactivation of vibrationally excited CO2 have important consequences for its ability to emit infrared radiation under atmospheric conditions. CO2 in its vibrational ground state may be excited to its vibrational excited state
CO2 (0110) by radiation with wavenumber 667.4 cm-1.This is the strongest infrared absorption of CO2 and therefore the main process for excitation of CO2 by infrared radiation from the earth’s surface. The vibrationally excited state CO2 (0110) emits radiation with a rate constant kr = 2.98 s -1 This state may be deactivated in bimolecular collisions with CO2 and N2 in their vibrational ground state. The deactivation rate may be calculated using data from J. A. Blauer and G.R. Nickerson, A survey of vibrational relaxation rate data for processes important to C02-N2-H20 infrared plume radiation. Prepared for Air Force Rocket Propulsion Laboratory, October 1973, Distributed by National Technical Information Service, US Department of Commerce, 5285 Port Royal Road, Springfield VA. 22151.
The rate constant for bimolecular deactivation by ground state CO2 or N2 depends on temperature T. For instance in the case 200 ppmv of CO2 in the air the rate of deactivation by collission with N2 amounts to 6.8 x 1014 s-1 at 288 K at ground level and to 5.5 x 1010 s-1 at 198.5 K and 80 km and above sea level. This means that as soon as a CO2 molecule gets excited by absorption of surface IR radiation to the state CO2 (0110) it has a negligible chance of emitting a photon. Therefore the entire observed 667.4 cm-1 radiation from the atmosphere must arise from the Boltzmann population of the state CO2 (0110). This holds even if the CO2 concentration is doubled. Therefore the statement of the IPCC concerning back radiation is untenable. Any observed 667 cm-1 radiation in the atmosphere originates from the sun, directly or through Raleigh scattering by CO2 in the upper atmosphere.

Oef, quite a bit, if I understand you correctly, You think CO2 molecules remain in their excited state for a longer time, making them inactive for further action.
Not from theory, but from real measurements, we know that in the CO2 window, the IR emitted at sealevel is far larger than outside the atmosphere, proving there is constant absorbtion.
How do you explain this.?

## Climatic variation since the last glaciation

Global warming is related to the more general phenomenon of climate change, which refers to changes in the totality of attributes that define climate. In addition to changes in air temperature, climate change involves changes to precipitation patterns, winds, ocean currents, and other measures of Earth’s climate. Normally, climate change can be viewed as the combination of various natural forces occurring over diverse timescales. Since the advent of human civilization, climate change has involved an “anthropogenic,” or exclusively human-caused, element, and this anthropogenic element has become more important in the industrial period of the past two centuries. The term global warming is used specifically to refer to any warming of near-surface air during the past two centuries that can be traced to anthropogenic causes.

To define the concepts of global warming and climate change properly, it is first necessary to recognize that the climate of Earth has varied across many timescales, ranging from an individual human life span to billions of years. This variable climate history is typically classified in terms of “regimes” or “epochs.” For instance, the Pleistocene glacial epoch (about 2,600,000 to 11,700 years ago) was marked by substantial variations in the global extent of glaciers and ice sheets. These variations took place on timescales of tens to hundreds of millennia and were driven by changes in the distribution of solar radiation across Earth’s surface. The distribution of solar radiation is known as the insolation pattern, and it is strongly affected by the geometry of Earth’s orbit around the Sun and by the orientation, or tilt, of Earth’s axis relative to the direct rays of the Sun.

Worldwide, the most recent glacial period, or ice age, culminated about 21,000 years ago in what is often called the Last Glacial Maximum. During this time, continental ice sheets extended well into the middle latitude regions of Europe and North America, reaching as far south as present-day London and New York City. Global annual mean temperature appears to have been about 4–5 °C (7–9 °F) colder than in the mid-20th century. It is important to remember that these figures are a global average. In fact, during the height of this last ice age, Earth’s climate was characterized by greater cooling at higher latitudes (that is, toward the poles) and relatively little cooling over large parts of the tropical oceans (near the Equator). This glacial interval terminated abruptly about 11,700 years ago and was followed by the subsequent relatively ice-free period known as the Holocene Epoch. The modern period of Earth’s history is conventionally defined as residing within the Holocene. However, some scientists have argued that the Holocene Epoch terminated in the relatively recent past and that Earth currently resides in a climatic interval that could justly be called the Anthropocene Epoch—that is, a period during which humans have exerted a dominant influence over climate.

Though less dramatic than the climate changes that occurred during the Pleistocene Epoch, significant variations in global climate have nonetheless taken place over the course of the Holocene. During the early Holocene, roughly 9,000 years ago, atmospheric circulation and precipitation patterns appear to have been substantially different from those of today. For example, there is evidence for relatively wet conditions in what is now the Sahara Desert. The change from one climatic regime to another was caused by only modest changes in the pattern of insolation within the Holocene interval as well as the interaction of these patterns with large-scale climate phenomena such as monsoons and El Niño/Southern Oscillation (ENSO).

During the middle Holocene, some 5,000–7,000 years ago, conditions appear to have been relatively warm—indeed, perhaps warmer than today in some parts of the world and during certain seasons. For this reason, this interval is sometimes referred to as the Mid-Holocene Climatic Optimum. The relative warmth of average near-surface air temperatures at this time, however, is somewhat unclear. Changes in the pattern of insolation favoured warmer summers at higher latitudes in the Northern Hemisphere, but these changes also produced cooler winters in the Northern Hemisphere and relatively cool conditions year-round in the tropics. Any overall hemispheric or global mean temperature changes thus reflected a balance between competing seasonal and regional changes. In fact, recent theoretical climate model studies suggest that global mean temperatures during the middle Holocene were probably 0.2–0.3 °C (0.4–0.5 °F) colder than average late 20th-century conditions.

Over subsequent millennia, conditions appear to have cooled relative to middle Holocene levels. This period has sometimes been referred to as the “Neoglacial.” In the middle latitudes this cooling trend was associated with intermittent periods of advancing and retreating mountain glaciers reminiscent of (though far more modest than) the more substantial advance and retreat of the major continental ice sheets of the Pleistocene climate epoch.

## Latest Posts

Solar cycles cause global warming

A new peer-reviewed study on Surface Warming and the Solar Cycle found that times of high solar activity are on average 0.2°C warmer than times of low solar activity, and that there is a polar amplification of the warming. This result is the first to document a statistically significant globally coherent temperature response to the solar cycle, the authors note (source: Surface warming by the solar cycle as revealed by the composite mean difference projection by Charles D. Camp and Ka Kit Tung. They find a global warming signal of 0.18°C attributable to the 11-year solar cycle. Eg - from solar minimum to solar maximum, global temperatures increase 0.18°C due to an increase in Total Solar Irradiance (TSI). To find the solar signal, they detrended the temperature data by removing the global warming trend. They found the detrended temperature correlated well with the solar cycle.

Figure 1: Detrended temperature (solid) compared to TSI (dotted) (Camp 2007)

However, a fair degree of climate variability contaminated the signal. Volcanic eruptions in 1982 and 1991 coincided with solar maximums. Similarly, the El Nino peak of 1998 occured during low solar activity. Tung and Camp filtered out the noise using various statistical techniques and found an even higher correlation with the solar cycle.

They concluded that from solar minimum to maximum (eg - from 1996 to 2001), the forcing from the sun increases global temperatures by 0.18°C. Conversely, from solar maximum to minimum (eg - from 2001 to 2007), the reduced forcing from the sun cools global temperatures by 0.18°C. This 11 year cycle is superimposed over the long term global warming trend.

### Climate Sensitivity

Camp and Tung explore the ramifications further in a follow-up paper Solar-Cycle Warming at the Earth&rsquos Surface and an Observational Determination of Climate Sensitivity. Independently of models, they calculate a climate sensitivity between 2.3 to 4.1°C. Eg - if CO2 levels are doubled, global temperatures will increase around 3.2°C. This confirms the IPCC estimate of climate sensitivity. In Tung's own words, "The finding adds to the evidence that mainstream climate models are right about the likely extent of future human-generated warming. It also effectively rules out some lower estimates in those models."

The other significant finding is that solar forcing will add another 0.18°C warming on top of greenhouse warming between 2007 (we're currently at solar minimum) to the solar maximum around 2012. In other words, solar forcing will double the amount of global warming over the next five to six years.

Last updated on 9 July 2010 by John Cook.

## 5 ways that climate change affects the ocean

For an ecosystem that covers 70 percent of the planet, oceans get no respect.

All they’ve done is feed us, provide most of the oxygen we breathe, and protect us from ourselves: Were it not for the oceans, climate change would have already made Earth uninhabitable.

The oceans have gamely absorbed more than 90 percent of the warming created by humans since the 1970s, a 2016 report found. Had that heat gone into the atmosphere, global average temperatures would have jumped by almost 56 degrees Celsius (100 degrees Fahrenheit).

But as vast as the seas are, there is a limit to how much they can absorb, and they are beginning to show it. Today, on World Oceans Day, Human Nature examines some of the ways that climate change affects life in the oceans — and what that means for humanity.

### 1. Higher temperatures are bad for fish — and for us

Persistently rising temperatures are having a cavalcade of effects on marine life. Consider:

• Warmer waters cause coral bleaching, which in turn impacts coral reef ecosystems that are home to most of the ocean’s biodiversity — and provide crucial sources of food for people.
• Warmer waters threaten to cause mass migration of marine species in search of the right conditions for feeding and spawning.
• Change in water temperatures can directly affect the development and growth of most fish and cephalopods (such as octopus and squid).

For the 3 billion people worldwide who rely on fish as their chief source of protein, the prospect of fewer and smaller fish in the sea is bad news.

### 2. Polar ice is melting

In what has become a dismal annual ritual, wintertime Arctic sea ice continues to dip to new lows as the oceans warm. Meanwhile, Antarctica is shrinking from underneath, as submerged ice is rapidly melting, according to recent studies.

The effects of this warming on iconic species such as polar bears are well-documented. Under the surface, though, the problem is no less urgent. Consider:

• The production of algae — the foundation of the Arctic food web — depends on the presence of sea ice. As sea ice diminishes, algae diminishes, which has ripple effects on species from Arctic cod to seals, whales and bears.
• Diminished sea ice results in the loss of vital habitat for seals, walruses, penguins, whales and other megafauna.
• Sea ice is a critical habitat for Antarctic krill, the food source for many seabirds and mammals in the Southern Ocean. In recent years, as sea ice has diminished, Antarctic krill populations have declined, resulting in declines in the species dependent on the krill.

What does this mean for us? Impacts to the Arctic cod fishery is having cascading effects, culminating in human-wildlife conflict, for one. A dramatic decrease in sea ice — and seafood — pushes polar bears toward coastal communities and hunting camps to find food, a nuisance and danger to people living there.

### 3. Rising sea levels represent a slow, seemingly unstoppable threat

Climate change poses a dual threat for sea levels.

For one, when land-based polar ice melts, it finds its way to the sea. (Ice that forms in polar seas, on the other hand, doesn’t affect sea levels when it melts.) Second, when water warms, it expands to take up more space — a major yet unheralded cause of sea-level rise.

With sea-level rise accelerating at a rate of about one-eighth of an inch per year, the effects on humanity are plain:

• Though only 2 percent of the world’s land lies at or below 10 meters (32 feet) above sea level, these areas contain 10 percent of the world’s human population, all directly threatened by sea-level rise.
• Small island nations such as those in the Pacific Ocean stand to be wiped off the map. The people of Kiribati, for example, are among the world’s first refugees of sea-level rise, and two of the nation’s islands have all but disappeared into the ocean.

The effects of sea-level rise on wildlife is less explored but no less important:

• The survival of coral reefs, mangroves, sea grasses and other critical habitat-forming species hinges on their ability to move into shallower waters. Slow-growing species are most unlikely to be able to keep pace with the rising sea level.
• Critical coastal habitats — for instance, sea turtle nesting beaches — are lost as the sea level rises. Natural and man-made barriers such as cliffs, sea walls, and coastal developments stand in the way of migrating further inland.

### 4. Warming oceans alter currents

Climate change impacts ocean temperatures as well as wind patterns — taken together, these can alter oceanic currents.

How does this affect wildlife?

As mentioned earlier, many marine species’ migratory patterns can change as the currents they follow are altered. And many species that depend on ocean currents for reproduction and nutrients will be affected. For example, many reef-building coral and reef fish species rely on dispersal of their larvae by currents.

The impacts of changes in ocean currents on humanity could be severe, as currents play a major role in maintaining Earth’s climate. For example, Europe’s relatively mild climate is maintained in part by the large Atlantic current called the Gulf Stream, which is experiencing an “unprecedented slowdown.” Changing these currents will have major implications for the climate across the globe, including changes in rainfall — with more rain in some areas and much less in others — and to air temperatures. These changes have drastic implications for countless species, including humans.

### 5. Climate change is affecting the chemistry of seawater

The same burning of fossil fuels that increases greenhouse gas levels in the atmosphere, is also altering the chemical composition of seawater, making it more acidic. The ocean absorbs 30 percent of the carbon dioxide in the atmosphere when that carbon dissolves into the water, it forms carbonic acid.

How does this affect marine life? A lot.

Acidification directly ocean life that build shells of calcium carbonate such as corals, scallops, lobsters and crabs, and some microscopic plankton that are a foundation of the food web throughout the ocean. These shell-forming organisms provide critical habitats and food sources for other organisms. Increased acidification can also limit the ability of certain fish to detect predators, disrupting the food chain.

The disruption and destruction of coral reefs and shellfish will have profound effects on humanity, chiefly in the form of less food for people who rely on the ocean for it.

Jessica Pink was an editorial intern for Conservation International.

## The Simplest Explanation Of Global Warming Ever

Earth energy budget diagram, with incoming and outgoing radiation (values are shown in W/m^2). . [+] Satellite instruments (CERES) measure the reflected solar, and emitted infrared radiation fluxes. The energy balance determines Earth's climate.

Let's play pretend for a moment. Pretend, if you can, that you've never heard about the idea of global warming before. Pretend you've never heard anyone else's opinions on the matter, including from politicians, scientists, friends or relatives. Pretend that there are no related concerns, like the economy, our energy needs, or the environment.

If you were going to make a genuine inquiry, there would instead be only two questions to ask and answer:

1. is the Earth warming or not,
2. and if so, what's the main cause?

This is a question that was tailor-made for the enterprise of science to answer. Here's how we can figure it out for ourselves.

There are really only two things that determine the Earth's temperature, or the temperature of any object that's heated by an external source. The first is the energy that goes into it, which is primarily energy produced by the Sun and absorbed by the Earth. The second is the energy that leaves the Earth, which is primarily due to the Earth radiating it away.

During the day, we absorb energy from the Sun this is the power inputted into the Earth. During both the day and the night, we radiate energy back into space that's the power outputted by the Earth. This is why temperatures heat up during the day and cool off during the night, something that’s pretty much true for every planet that has both a day side and a night side.

The Earth and Moon, to scale, in terms of both size and albedo/reflectivity. Note how much fainter . [+] the Moon appears, as it absorbs light much better than Earth does.

To know what the temperature of Earth ought to be, we need to first understand the energy that comes into our world. The source of this energy is the Sun, which radiates with a very well-measured power: 3.846 × 10 26 watts. The closer you are to the Sun, the more of this energy you absorb, while the farther away you are, the less you absorb. Over the timespan that we've measured the Sun's power output, it's varied by only about ±0.1%.

The anatomy of the Sun, including the inner core, which is the only place where fusion occurs. Even . [+] at the incredible temperatures of 15 million K, the maximum achieved in the Sun, the Sun produces less energy-per-unit-volume than a typical human body. The Sun's volume, however, is large enough to contain over 10^28 full-grown humans, which is why even a low rate of energy production can lead to such an astronomical total energy output.

Sunlight spreads out in a sphere the farther away you are from it, meaning that if you're twice as far away from the Sun, you only absorb one-quarter the radiation. At Earth's distance from the Sun, we encounter a power of around 1,361 watts-per-square-meter that's how much hits the top of our atmosphere.

The Earth also orbits in an ellipse around the Sun, meaning that at some points it's closer to the Sun, absorbing more radiation, while at other times it's more distant, absorbing less. The variation from this effect is more like ±1.7%, with the largest amount of energy absorbed occurring in early January, and the least amount occurring in early July.

The way that sunlight spreads out as a function of distance means that the farther away from a power . [+] source you are, the energy that you intercept drops off as one over the distance squared.

Wikimedia Commons user Borb

But that's not the full story. The sunlight that hits us comes in a variety of wavelengths: ultraviolet, visible, and infrared, all of which carry energy. The atmosphere has many layers, some of which absorb that light, some of which allow it to transmit all the way down to the ground, and some of which reflect it back into space.

All told, about 77% of the energy from the Sun makes it down to Earth's surface when the Sun is directly overhead, with that number dropping significantly when the Sun is lower on the horizon.

The atmosphere of the Earth, although only 5.15 x 10^18 kilograms in mass (just under 0.0001% of the . [+] Earth's mass), plays a tremendous role in defining the properties of our surface.

Cosmonaut Fyodor Yurchikhin / Russian Space Agency Press Services

Some of that energy gets absorbed by Earth's surface, while some of it gets reflected. Clouds reflect sunlight better than average, as do dry sand and icecaps. Other ground conditions are better at absorbing sunlight, including oceans, forests, wet soil, and savannahs. Depending on seasonal conditions on Earth, the individual locations on Earth vary tremendously in how much light they reflect or absorb.

On average, however, the Earth is very consistent: 31% of the incident radiation gets reflected, while 69% gets absorbed. As far as global effects go, this average has changed remarkably little over time, even as human civilization has transformed the landscape of our planet.

Although various components of the Earth's surface display huge variable ranges in the amount of . [+] light they absorb or reflect, the global average reflectance/absorption of Earth, known as albedo, has remained constant at

Ken Gould, New York State Regents Earth Science

When we put in all the factors we know of:

• the Sun's power output,
• the Earth's physical size and distance from the Sun,
• the amount of sunlight that Earth absorbs vs. reflects,
• and the intrinsic variability in the Sun over time,

we can arrive at a way to calculate the average temperature of the Earth.

We calculate that Earth should be at 255 Kelvin (-18 °C / 0 °F), or well below freezing. And that's absurd, and completely not reflective of reality.

The Earth as viewed from a composite of NASA satellite images from space in the early 2000s. Note . [+] the abundant presence of liquid water on the surface: an indicator of a temperate climate.

NASA / Blue Marble Project

Instead, our planet has an average temperature of 288 Kelvin (15 °C / 59 °F), which is much warmer than the naive predictions we just painstakingly calculated. Our world is temperate, not frozen, and there's one big reason for these predictions and observations to be so thoroughly off from one another: we've been ignoring the insulating effects of Earth's atmosphere.

Sure, the Earth radiates the energy it absorbs back into space. But it doesn't all go into space straightaway the same atmosphere that wasn't 100% transparent to sunlight also isn't 100% transparent to the infrared light that Earth radiates. The atmosphere is made up of molecules that absorb radiation of varying wavelengths, depending on what the atmosphere is made out of.

The interplay between the atmosphere, clouds, moisture, land processes and the oceans all governs . [+] the evolution of Earth's equilibrium temperature.

NASA / Smithsonian Air & Space Museum

For infrared radiation, nitrogen and oxygen — the majority of our atmosphere — act as though they're virtually transparent. But there are three gases that are part of our atmosphere which aren't transparent at all to the radiation Earth produces:

All three of these gases, when they're present in any planet's atmosphere, act the same way a blanket does when you place it over a warm-blooded animal's body: they prevent the heat from escaping.

An emaciated orphaned elephant calf was rescued from the wild after tourists spotted him struggling. . [+] Kenya Wildlife Service and David Sheldrick Wildlife Trust responded to reports of the wandering calf on March 18 and dispatched a rescue team to pick up the calf. Here, a blanket was placed over the elephant calf to help it retain its body heat: an extremely effective technique that humans take for granted in our daily lives.

THE DSWT / Barcroft Images / Barcroft Media via Getty Images

In the case of an animal, they need to generate less of their own heat to maintain a constant temperature when there's a blanket on them. And if the blanket is thicker, or if there are a greater number of thin blankets, they need to generate even less. This analogy extends to layers of clothing in any conditions the more insulation you have around you, the less heat escapes, allowing you to maintain higher temperatures.

For a planet like ours, these gases prevent the infrared radiation from escaping, instead absorbing it and re-radiating it back to Earth. The more of these gases that are present, the longer and more efficiently Earth holds onto the Sun's heat. We can't change the energy input, so instead, as we add additional amounts of these gases, the temperature of our world simply goes up.

The concentration of carbon dioxide in Earth's atmosphere can be determined from both ice core . [+] measurements, which easily go back hundreds of thousands of years, and by atmospheric monitoring stations, like those atop Mauna Loa. The increase in atmospheric CO2 since the mid-1700s is staggering, and continues unabated.

The water vapor content is something that's determined by Earth's oceans, the local temperature, humidity and dew point. When we add more water vapor to the atmosphere or take water vapor out of it, the overall water vapor content doesn't change at all. As far as human activity goes, nothing we do has any impact on the net amount of H2O in the atmosphere.

The concentrations of the other two gases (CO2 and CH4), though, are primarily determined by human influence. It's well-documented, for example, that CO2 has risen by more than 50% of its 1700s-era value due to the burning of fossil fuels coinciding with the start of the industrial revolution. According to NASA scientist Chris Colose:

50% of the 33 K greenhouse effect is due to water vapor, about 25% to clouds, 20% to CO2, and the remaining 5% to the other non-condensable greenhouse gases such as ozone, methane, nitrous oxide, and so forth.

At an average warming rate of 0.07º C per decade for as long as temperature records exist, the . [+] Earth's temperature has not only increased, but continues to increase without any relief in sight.

NOAA National Centers for Environmental information, Climate at a Glance: Global Time Series

All of this leads to a very straightforward conclusion: if we increase the concentrations of infrared-absorbing gases in our atmosphere, like CO2 and CH4, the Earth's temperature will rise. Given that the temperature record unequivocally shows that the Earth is warming, and we have put these additional proverbial blankets onto our atmosphere, it seems like a slam dunk that this is cause-and-effect at work.

It cannot be proven that human activity is the cause of global warming, of course. That conclusion we drew is still a scientific inference. But based on what we know about planetary science, Earth’s atmosphere, human activity and the warming we’re observing, it seems like a very good one. When we quantify the other effects, it's unlikely that anything else could be the cause. Not the Sun, not volcanoes, not any natural phenomenon that we know of.

The Earth is warming, and humans are the cause. The next steps — of what to do about it — are 100% up to us.

## A global shift

It's a no brainer. A shift away from environmentally damaging meat and dairy production, to a cleaner, healthier plant-based food system is better for everyone. The United Nations was one of the first global institutions to point out that we need to reduce our dependence on animal products to avoid environmental destruction, and since then many influential voices &mdash from business leaders and NGOs to multinational corporations &mdash have joined the chorus.

Climate action group One Million Women has been talking about it for years. As has The Climate Council. Climate guru Al Gore, who comes from a line of cattle ranchers, is now vegan. There are schools all over the world that are adopting 'Meat Free Mondays' to teach students about sustainability and to reduce their eco footprint. Much like IKEA did when they introduced 'veggie balls' to their menu.

Meanwhile, the Stockholm International Water Institute is warning that we must reduce global animal product consumption to just 5% of our calorie intake by 2050 to make sure we don't run out of fresh water. And Greenpeace is now encouraging its global followers to reduce their meat consumption &mdash or ditch it altogether:

Veganuary &mdash a charity that encourages people to try vegan for January &mdash had a record-number of sign-ups in 2018, more than doubling the previous year. While plant-based dairy and meat is flying off supermarket shelves &mdash and that's according to Australia's leading 'beef' news site!

Which goes to show there's a massive appetite out there for delicious plant-based food (forgive the pun) that helps the environment, improves personal health and reduces the suffering of animals.

All of which begs the question: exactly when will our policymakers catch up?

With a Prime Minister who is warning us not to get "distracted by ideological debate" when it comes to climate change, and is failing to prioritise Australia's international climate obligations, it doesn't seem likely that calls for a meat tax (to help offset meat's significant financial burden on the environment and public health system) will be adopted any time soon.

So despite the fact meat and dairy are some of the greatest polluters of all, political focus remains stubbornly fixed on the energy we use to power our homes, rather than our bodies. In fact, the current government has no emissions reductions policies &mdash in the energy or agricultural sectors! But that isn't stopping Prime Minister Morrison insisting that Australia will meet our Paris climate commitments. How? Well, according to the PM "the business-as-usual model gets us there in a canter".

He doesn't seem to understand that how we're currently operating &mdash "business-as-usual" &mdash is actually cantering Australia, and the world, towards a cliff.

## What is the Extent of the Greenhouse Effect?

If you read data from the EPA, you will find some rather horrifying things about the Greenhouse Effect. The total warming effect humans have had on the environment increased by 37% between 1990 and 2015.

Some harmful gases are present naturally like carbon dioxide, methane, water vapor, and nitrous oxide while others are human-made like chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs). The natural greenhouse effect has reached a critical level, and the human activities are making the situation even worse.

What is the impact of all of these greenhouse gases accumulating? The earth’s temperature is rising to incredible levels. According to Yale E360, 2017 was the warmest year on record.

## 7 Answers to Climate Contrarian Nonsense

President Donald Trump has consistently opposed fighting climate change. His administration loosened fuel economy and emissions standards for new motor vehicles, for example&mdasha measure that automakers had not even requested. He replaced the Clean Power Plan championed by his predecessor, President Barack Obama, with new regulations that permit more carbon emissions from coal- and gas-burning power plants. In November 2019 he even initiated the year-long process of withdrawing the U.S. from the Paris climate accords, an agreement that required nothing from its signatories except an unenforced pledge to help keep the rise in global temperatures below two degrees Celsius.

The reasoning behind those actions has been hard to pin down. Trump has repeatedly denounced global warming as a &ldquohoax&rdquo and a Chinese plot to undermine U.S. manufacturing. But then, in a January 2019 press conference, Trump also said &ldquonothing&rsquos a hoax&rdquo about climate change. Many of those he had named to head various agencies, including Rick Perry at the Department of Energy and Scott Pruitt at the Environmental Protection Agency, questioned or denied the role of carbon dioxide in climate change. But when reporters have directly asked whether Trump believes global warming is real, White House press secretaries have skirted the question. It&rsquos hard to tell whether his administration is skeptical about the scientific fact of the climate crisis or simply the urgency of doing anything about it.

Ambiguity has often been weaponized by those who prefer to call themselves &ldquoclimate skeptics&rdquo&mdashalthough they generally seem to be more dedicated to naysaying than to genuine skeptical inquiry. Not everyone who questions climate change science fits that description, of course: some people are genuinely unaware of the facts or honestly disagree about their interpretation. What distinguishes the true naysayers is their dedicated opposition to conceding that there is an actionable problem, often with long-disproved arguments about alleged weaknesses in the science of climate change.

What follows is a partial list of the contrarians&rsquo bad-faith arguments and some brief rebuttals of them.

CLAIM 1: Anthropogenic carbon dioxide can&rsquot be changing climate, because CO2 is only a trace gas in the atmosphere and the amount produced by humans is dwarfed by the amount from volcanoes and other natural sources. Water vapor is by far the most important greenhouse gas, so changes in CO2 are irrelevant.

Although carbon dioxide makes up only 0.04 percent of the atmosphere, that small number plays a significant role in climate dynamics. Even at that low concentration, CO2 absorbs infrared radiation and acts as a greenhouse gas, as physicist John Tyndall demonstrated in 1859. Chemist Svante Arrhenius went further in 1896 by estimating the impact of CO2 on the climate after painstaking hand calculations, he concluded that doubling its concentration might cause almost six degrees Celsius of warming&mdashan answer not much out of line with recent, far more rigorous computations.

Forests remove atmospheric CO2 and offset the nonhuman releases of CO2. Human activity, combined with forest clearing (shown here), negates this process, however. Credit: Joel W. Rogers Getty Images

Contrary to the contrarians, human activity is by far the largest contributor to the observed increase in atmospheric CO2. According to the Global Carbon Project, anthropogenic CO2 amounts to about 35 billion tons annually&mdashmore than 130 times as much as volcanoes produce. True, 95 percent of the releases of CO2 to the atmosphere are natural, but natural processes such as plant growth and absorption into the oceans pull the gas back out of the atmosphere and almost precisely offset them, leaving the human additions as a net surplus. Moreover, several sets of experimental measurements, including analyses of the shifting ratio of carbon isotopes in the air, further confirm that fossil-fuel burning and deforestation are the primary reasons that CO2 levels have risen 45 percent since 1832, from 284 parts per million (ppm) to 412 ppm&mdasha remarkable jump to the highest levels seen in millions of years.

Contrarians frequently object that water vapor, not CO2, is the most abundant and powerful greenhouse gas they insist that climate scientists routinely leave it out of their models. The latter is simply untrue: from Arrhenius on, climatologists have incorporated water vapor into their models. In fact, water vapor is why rising CO2 has such a big effect on climate. CO2 absorbs some wavelengths of infrared that water does not, so it independently adds heat to the atmosphere. As the temperature rises, more water vapor enters the atmosphere and multiplies CO2&rsquos greenhouse effect the Intergovernmental Panel on Climate Change (IPCC) notes that water vapor may &ldquoapproximately double the increase in the greenhouse effect due to the added CO2 alone.&rdquo

Climate contrarians argue that variation in solar energy reaching the planet is behind global warming. But human influence has a measurably stronger effect on climate. Credit: NASA

Nevertheless, within this dynamic, the CO2 remains the main driver (what climatologists call a &ldquoforcing&rdquo) of the greenhouse effect. As NASA climatologist Gavin Schmidt has explained, water vapor enters and leaves the atmosphere much more quickly than CO2 and tends to preserve a fairly constant level of relative humidity, which caps off its greenhouse effect. Climatologists therefore categorize water vapor as a feedback rather than a forcing factor. (Contrarians who don&rsquot see water vapor in climate models are looking for it in the wrong place.)

Because of CO2&rsquos inescapable greenhouse effect, contrarians holding out for a natural explanation for current global warming need to explain why, in their scenarios, CO2 is not compounding the problem.

CLAIM 2: The alleged &ldquohockey stick&rdquo graph of temperatures over the past 1,600 years has been disproved. It doesn&rsquot even acknowledge the existence of a &ldquomedieval warm period&rdquo around a.d. 1000 that was hotter than today is. Therefore, global warming is a myth.

It is hard to know which is greater: contrarians&rsquo overstatement of the flaws in the historical temperature reconstruction from 1998 by Michael E. Mann and his colleagues or the ultimate insignificance of their argument to the case for climate change.

First, there is not simply one hockey-stick reconstruction of historical temperatures using one set of proxy data. Similar evidence for sharply increasing temperatures over the past couple of centuries has turned up independently while looking at ice cores, tree rings and other proxies for direct measurements, from many locations. Notwithstanding their differences, they corroborate that the planet has been getting sharply warmer.

A 2006 National Research Council review of the evidence concluded &ldquowith a high level of confidence that global mean surface temperature was higher during the last few decades of the 20th century than during any comparable period during the preceding four centuries&rdquo&mdashwhich is the section of the graph most relevant to current climate trends. The report placed less faith in the reconstructions back to a.d. 900, although it still viewed them as &ldquoplausible.&rdquo Medieval warm periods in Europe and Asia with temperatures comparable to those seen in the 20th century were therefore similarly plausible but might have been local phenomena: the report noted &ldquothe magnitude and geographic extent of the warmth are uncertain.&rdquo And a research paper by Mann and his colleagues seems to confirm that the Medieval Warm Period and the &ldquoLittle Ice Age&rdquo between 1400 and 1700 were both caused by shifts in solar radiance and other natural factors that do not seem to be happening today.

After the NRC review was released, another analysis by four statisticians, called the Wegman report, which was not formally peer-reviewed, was more critical of the hockey-stick paper. But correction of the errors it pointed out did not substantially change the shape of the hockey-stick graph. In 2008 Mann and his colleagues issued an updated version of the temperature reconstruction that echoed their earlier findings.

But hypothetically, even if the hockey stick was busted . What of it? The case for anthropogenic global warming originally came from studies of climate mechanics, not from reconstructions of past temperatures seeking a cause. Warnings about current warming trends came out years before Mann&rsquos hockey-stick graph. Even if the world were incontrovertibly warmer 1,000 years ago, it would not change the fact that the recent rapid rise in CO2 explains the current episode of warming more credibly than any natural factor does&mdashand that no natural factor seems poised to offset further warming in the years ahead.

CLAIM 3: Global warming stopped in 1998 Earth has been cooling since then.

This contrarian argument might be the most obsolete and unintentionally hilarious. Here&rsquos how it goes: 1998 was the world&rsquos warmest year, according to the U.K. Met Office Hadley Center&rsquos records the following decade was cooler therefore, the previous century&rsquos global warming trend is over, right?

Anyone with even a glancing familiarity with statistics should be able to spot the weaknesses of that argument. Given the extended duration of the warming trend, the expected (and observed) variations in the rate of increase and the range of uncertainties in the temperature measurements and forecasts, a decade&rsquos worth of mild interruption is too small a deviation to prove a break in the pattern, climatologists say.

If a lull in global warming had continued for another decade, would that have vindicated the contrarians&rsquo case? Not necessarily, because climate is complex. For instance, Mojib Latif, then at the Leibniz Institute of Marine Sciences in Germany, and his colleagues published a paper in 2008 that suggested ocean-circulation patterns might cause a period of cooling in parts of the Northern Hemisphere, even though the long-term pattern of warming remained in effect. Fundamentally, contrarians who have resisted the abundant evidence that supports warming should not be too quick to leap on evidence that only hints at the opposite.

In any case, the claim that a &ldquowarming pause&rdquo disproved ongoing climate change became completely academic when 1998 stopped being the warmest year on record. That title now belongs to 2016, with 2019 right behind it. In fact, the past 15 years have included all 10 of the hottest years on record.

CLAIM 4: The sun or cosmic rays are much more likely the real causes of global warming. After all, Mars is warming up, too.

Astronomical phenomena are obvious natural factors to consider when trying to understand climate, particularly the brightness of the sun and details of Earth&rsquos orbit because those seem to have been major drivers of the ice ages and other climate changes before the rise of industrial civilization. Climatologists, therefore, do take them into account in their models. But in defiance of the naysayers who want to chalk the recent warming up to natural cycles, there is insufficient evidence that enough extra solar energy is reaching our planet to account for the observed rise in global temperatures.

The IPCC has noted that between 1750 and 2005, the radiative forcing from the sun increased by 0.12 watt per square meter&mdashless than a tenth of the net forcings from human activities (1.6 W/ m 2 ). The largest uncertainty in that comparison comes from the estimated effects of aerosols in the atmosphere, which can variously shade Earth or warm it. Even granting the maximum uncertainties to these estimates, however, the increase in human influence on climate exceeds that of any solar variation.

Moreover, remember that the effect of CO2 and the other greenhouse gases is to amplify the sun&rsquos warming. Contrarians looking to pin global warming on the sun can&rsquot simply point to any trend in solar radiance: they also need to quantify its effect and explain why CO2 does not consequently become an even more powerful driver of climate change. (And is what weakens the greenhouse effect a necessary consequence of the rising solar influence or an ad hoc corollary added to give the desired result?)

Contrarians therefore gravitated toward work by Henrik Svensmark of the Technical University of Denmark, who argued that the sun&rsquos influence on cosmic rays needed to be considered. Cosmic rays entering the atmosphere help to seed the formation of aerosols and clouds that reflect sunlight. In Svensmark&rsquos theory, the high solar magnetic activity over the past 50 years shielded Earth from cosmic rays and allowed exceptional heating, but now that the sun is more magnetically quiet again, global warming would reverse. Svensmark claimed that, in his model, temperature changes correlate better with cosmic-ray levels and solar magnetic activity than with other greenhouse factors.

Svensmark&rsquos theory failed to persuade most climatologists, however, because of weaknesses in its evidence. In particular, there do not seem to be clear long-term trends in the cosmic-ray influxes or in the clouds that they are supposed to form, and his model does not explain (as greenhouse explanations do) some of the observed patterns in how the world is getting warmer (such as that more of the warming occurs at night). For now, at least, cosmic rays remain a less plausible culprit in climate change.

And the apparent warming seen on Mars? Because it is based on a very small base of measurements, it may not represent a true trend. Too little is yet known about what governs the Martian climate to be sure, but a period when there was a darker surface might have increased the amount of absorbed sunlight and raised temperatures.

Elevated CO2 makes oceans acidic, which could have irreversible harmful effects on coral reefs, such as coral bleaching (shown here). Credit: Getty Images

CLAIM 5: Climatologists conspire to hide the truth about global warming by locking away their data. Their so-called consensus on global warming is scientifically irrelevant because science isn&rsquot settled by popularity.

It is virtually impossible to disprove accusations of giant global conspiracies to those already convinced of them (can anyone prove that the Freemasons and the Roswell aliens aren&rsquot involved, too?). Let it therefore be noted that the magnitude of this hypothetical conspiracy would need to encompass many thousands of uncontroversial publications and respected scientists from around the world, stretching back through Arrhenius and Tyndall for almost 150 years. A conspiracy would have to be so powerful that it has co-opted the official positions of dozens of scientific organizations, including the U.S. National Academy of Sciences, the U.K.&rsquos Royal Society, the American Association for the Advancement of Science, the American Geophysical Union, the American Institute of Physics and the American Meteorological Society.

If there were a massive conspiracy to defraud the world on climate (and to what end?), surely the thousands of e-mails and other files stolen from the University of East Anglia&rsquos Climatic Research Unit in England and distributed by hackers in 2009 would bear proof of it. None did. Most of the few statements from those e-mails that critics claimed as evidence of malfeasance had more innocent explanations that make sense in the context of scientists conversing privately and informally. If any of the scientists involved manipulated data dishonestly or thwarted Freedom of Information requests, it would have been deplorable however, there is no evidence that happened. What is missing is any clear indication of a widespread attempt to falsify and coordinate findings on a scale that could hold together a global cabal or significantly distort the record on climate change.

Climatologists are often frustrated by accusations that they are hiding data or the details of their models because, as NASA&rsquos Schmidt points out, much of the relevant information is in public databases or otherwise accessible&mdasha fact that contrarians conveniently ignore when insisting that scientists stonewall their requests. (And because nations differ in their rules on data confidentiality, scientists are not always at liberty to comply with some requests.) If contrarians want to deal a devastating blow to global warming theories, they should use the public data and develop their own credible models to demonstrate sound alternatives.

Yet that rarely occurs. In 2004 historian of science Naomi Oreskes published a landmark analysis of the peer-reviewed literature on global warming, &ldquoThe Scientific Consensus on Climate Change.&rdquo Out of 928 papers whose abstracts she surveyed, she wrote, 75 percent explicitly or implicitly supported anthropogenic global warming, 25 percent were methodological or otherwise took no position on the subject&mdashand none argued for purely natural explanations. Notwithstanding some attempts to debunk Oreskes&rsquos findings that eventually fell apart, her conclusion stands.

Oreskes&rsquos work does not mean that all climate scientists agree about climate change&mdashobviously, some do not (although they are very much a minority). Rather the meaningful consensus is not among the scientists but within the science: the overwhelming predominance of evidence for greenhouse-driven global warming that cannot easily be overturned even by a few contrary studies. (Oreskes currently is a columnist for Scientific American.)

CLAIM 6: Climatologists have a vested interest in raising the alarm because it brings them money and prestige.

If climate scientists are angling for more money by hyping fears of climate change, they are not doing so very effectively. According to the U.S. Government Accountability Office, between 1993 and 2014 federal spending on climate change research, technology, international assistance and adaptation rose from $2.4 billion to$11.6 billion. (An additional $26.1 billion was also allocated to climate change programs and activities by the economic stimulus package of the American Recovery and Reinvestment Act in 2009. Total federal nondefense spending on research in 2014 exceeded$65 billion.) Yet the scientific research share of that money fell sharply throughout that period: most of the budgeted money went to energy-conservation projects and other technology programs. Climatologists&rsquo funding therefore stayed almost flat, whereas others, including those in industry, benefited handsomely. Surely the Freemasons could do better than that.

CLAIM 7: Technological fixes, such as inventing energy sources that don&rsquot produce CO2 or geoengineering the climate, would be more affordable, prudent ways to address climate change than reducing our carbon footprint.

Critics of standard policy responses to climate change have often seemed to imply that environmentalists are obsessed with regulatory reductions in CO2 emissions and uninterested in technological solutions. That interpretation is at best bizarre: such innovations in energy efficiency, conservation and production are exactly what caps or levies on CO2 are meant to encourage.

The relevant question is whether it is prudent for civilization to defer curbing or reducing its CO2 output before such technologies are ready and can be deployed at the needed scale. The most common conclusion is no. Remember that as long as CO2 levels are elevated, additional heat will be pumped into the atmosphere and oceans, extending and worsening the climate consequences. As climatologist James Hansen of the Earth Institute at Columbia University has pointed out, even if current CO2 levels could be stabilized overnight, surface temperatures would continue to rise by 0.5 degree C over the next few decades because of absorbed heat being released from the ocean. The longer we wait for technology alone to reduce CO2, the faster we will need for those solutions to pull CO2 out of the air to minimize the warming problems. Minimizing the scope of the challenge by restricting the accumulation of CO2 only makes sense.

Moreover, climate change is not the only environmental crisis posed by elevated CO2: it also makes the oceans acidic, which could have irreversibly harmful effects on coral reefs and other marine life. Only the immediate mitigation of CO2 release can contain those losses.

Much has already been written on why schemes for geoengineering&mdashaltering Earth&rsquos climate systems by design&mdashseem ill advised except as a desperate last-chance strategy for dealing with climate change. The more ambitious proposals involve largely untested technologies, so it is unclear how well they would achieve their desired purpose even if they did curb warming, they might cause other significant environmental problems in the process. Methods that did not remove CO2 from the air would have to be maintained in perpetuity to prevent drastic rebound warming. And the governance of the geoengineering system could become a political minefield, with nations disagreeing about what the optimal climate settings should be. And of course, as with any of the other technological solutions, reducing the emission and accumulation of CO2 in the atmosphere first would only make any geoengineering solution easier.

All in all, counting on future technological developments to solve climate change rather than engaging with the problem straightforwardly by all available means, including regulatory ones, seems like the height of irresponsibility. But then again, responsible action on climate change is what the contrarians seem most interested in denying.

### MORE TO EXPLORE

Global-Scale Temperature Patterns and Climate Forcing over the Past Six Centuries. Michael E. Mann, Raymond S. Bradley and Malcolm K. Hughes in Nature, Vol. 392, pages 779&ndash787 April 23, 1998.

Climate Change 2014: Synthesis Report. Working Groups I, II and III of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, 2014. Available at www.ipcc.ch/report/ar5/syr

The Consensus on Anthropogenic Global Warming Matters. James L. Powell in Bulletin of Science, Technology and Society, Vol. 36, No. 3 2016. Published online May 24, 2017.

## Does global warming have an impact on the stratospheric ozone layer?

Since the 1960s, there has been a trend of increasing warming of the lower atmosphere and a cooling of the upper atmosphere. This warming-cooling dynamic creates conditions that lead to ozone loss.

Observations show that as greenhouse gases increase and result in heating in the lower atmosphere (troposphere), a cooling is occurring in the upper atmosphere (stratosphere). Largely because heat from Earth's surface that normally would convey through the troposphere and stratosphere, and eventually escape to space, is now being trapped (or confined to the troposphere).

The increasing temperatures at the Earth's surface and decreasing temperatures in higher parts of the atmosphere can be partly explained using the blanket analogy.

Carbon dioxide and other heat-trapping gases rise into the atmosphere and spread around the globe, like a blanket wrapping Earth. This blanket warms the surface of the Earth and protects it from the cold air above it.

The increased concentrations of heat-trapping gases make the blanket uncomfortably thicker. Wrapped now in a thicker blanket, Earth’s surface warms up, heats the blanket itself, and traps more heat in the lower atmosphere.

The blanket also prevents heat from moving from the lower atmosphere to the stratosphere, cooling down the stratosphere as a result.

In other words, heat-trapping gases contribute to creating the cooling conditions in the atmosphere that lead to ozone depletion. Greenhouse gases absorb heat at relatively low altitudes and warm the surface--but they have the opposite effect in higher altitudes because they prevent heat from rising.

In a cooler stratosphere, ozone loss creates a cooling effect that results in further ozone depletion. UV radiation releases heat into the stratosphere when it reacts with ozone. With less ozone there is less heat released, amplifying the cooling in the lower stratosphere, and enhancing the formation of ozone-depleting polar stratospheric clouds, especially near the South Pole.