The NTS program presentation for today is Anthropogenic Global Warming.
Some members will be participating by Skype. To join the discussion on Skype connect to prasadgolla75075.
A PDF copy of the presentation is on-line here.
Phone Prasad Golla if you have problems connecting: 972 351 3342
This is being reposted from the Skeptical Analysis blog in conjunction with our planned discussion of anthropogenic global warming (AGW).
I will try to keep the introduction brief. It’s a little bit of physics that I was supposed to have learned a long time ago but retained only a little.
The planet Earth reflects about 30% of the light it gets from the sun. One way of saying this is the albedo of the Earth is 30%. Wikipedia says 30% to 35%, but I was only guessing. The remaining 65% to 70% the Earth gets to keep, and this warms the Earth.
Keep this in mind. The Earth does not keep this energy forever. If it did, then the Earth would keep getting hotter and hotter until it melted, and we know that has not happened recently. When the surface of the Earth is warm it radiates invisible infra-red energy out into space. The hotter the surface becomes the more intensely it radiates energy. After a time the Earth’s surface reaches a temperature at which the combined reflected and radiated energy exactly equal the energy received from the sun. This is a system in equilibrium.
OK, that’s not strictly true. One problem we poor students had to solve was to calculate this average surface temperature. The solution was about 20 degrees F cooler than what we actually measure. What was wrong? What was wrong, and we knew this going in, is that the sun is not the sole source of heating for the Earth. The Earth contains within it a vast nuclear reactor, large quantities of uranium and thorium undergoing radioactive decay and releasing heat. Enough heat to keep the Earth’s average surface temperature where it is now. Which some would say is just about right.
Electromagnetic energy (including visible light and infra-red) must pass through the Earth’s atmosphere coming in and going out. The atmosphere intercepts some of that energy passing through in both directions. To get to the point, the Earth’s surface reflects some visible light and some infra-red, but it (mostly) only emits energy in the form of infra-red radiation. Without consulting any charts I am going to say a large amount of infra-red energy passes through the atmosphere on the way out into infinite space, never to return again. But some of this infra-red making the trip out gets absorbed by the atmosphere.
This illustration from Wikipedia shows what goes on with energy and radiation in this circumstance. The plots for an idealized absorber/emitter show that as surface temperature increases, the body emits more energy and preferentially in the short wavelengths (for example, visible light). When the surface temperature is lower the total emission is less, and the distribution is concentrated in the longer wavelengths (infra-red). At ordinary surface temperatures on Earth (especially not the glowing lava from a volcano) the emission is entirely in the infra-red and longer wavelengths.
So, what would happen if the amount of energy getting absorbed on the way out were to increase? To answer my own question, more energy would be retained by the Earth as a whole (atmosphere plus ground plus water). The temperature of the Earth’s surface would rise until it reached a point that the amount of energy starting the trip out would be enough so that enough would make it out, and the inward and outward flows would balance again.
What would cause the atmosphere to increase its infra-red absorption rate (absorb a greater fraction of the infra-red passing through)? The answer is “some change in the nature of the atmosphere.”
The atmosphere is mostly nitrogen and oxygen gas. Water vapor makes up some, and argon gas and carbon dioxide make up even less. Due to some well-known principles of quantum mechanics, water molecules interact readily with photons in the infra-red part of the spectrum. Water molecules have a number of energy levels at which to store energy, and certain wavelengths of infra-red have just the right energy to raise the energy of a water molecule by the amount of the difference of two of the molecule’s well-defined energy levels. A water molecule readily interacts with a photon of the proper wavelength and absorbs all of its energy. This kind of interaction likes to be all or nothing. That’s why they call it quantum mechanics.
So, water vapor in the atmosphere is an excellent absorber of infra-red energy and contributes greatly to keeping the Earth’s surface warm. What about carbon dioxide? The same is true with carbon dioxide, but not so much, because, for one thing, there is much less of it. Water accounts for 36% to 72% of the I-R absorption, and CO2 accounts for 9% to 26%. CO2 makes up 0.039% of the atmosphere, while water makes up about 0.4%. It’s apparent that of the two major “greenhouse” gasses in the air, CO2 is pound for pound more absorbent of infra-red than water.
People who doubt the effect that something like water has on heat retention need to visit a desert climate. In Tucson, Arizona, the relative humidity may linger around 10%, and in the day time the temperature regularly exceeds 110F. When the sun goes down you look up, and you see nothing between you and the cold void of outer space but a layer of dry air. The temperature rapidly drops as energy radiates into space. The sky “feels” cold. A demonstration with CO2 uses an IR imaging system and a CO2 fire extinguisher. On the imaging view screen you can see all manner of objects in a completely dark room, because they emit IR. Spray a cloud of CO2 in front of these objects, and they disappear, because the CO2 has absorbed the IR.
Even so, water has a greater over-all effect on heat retention in the atmosphere, so what’s all the fuss about CO2? We regularly put a lot of water in the air and never give it a thought. The difference is that water has a transport mechanism called “rain” that removes it from the atmosphere as fast on average as it goes in. CO2 has no such mechanism. CO2 is removed mainly by the process of photosynthesis by plants, and it takes a long time to remove a large slug of CO2 from the air. The average life of a water molecule in the air is about 9 days. The average life of a CO2 molecule in the air is 20 years. That large slug of CO2 will show effects for about 200 years.
That was my brief introduction, and I now get down to the business of what has come to be called global warming. The CO2 concentration in the air has gone up 35% since the advent of the industrial revolution, and it appears that much of this has been due to the burning of fossil fuels and the destruction of forests.
Carbon dioxide is just carbon and oxygen joined into a molecule. The atmosphere contains a lot of oxygen (about 21%) but no carbon except in carbon dioxide, methane and some other minor gasses. If you can manage the carbon, you can keep the CO2 out of the atmosphere. Fossil fuels (coal-almost pure carbon and hydrocarbons-petroleum and natural gas) transport carbon, that has been sequestered underground for millions of years, back to the atmosphere. Trees store a lot of carbon, as well, and removing them without growing new ones to replace them returns their carbon content of the atmosphere.
None of that would matter if there were not detrimental effects of global warming. Nobody has yet projected more than a two to five degrees rise in atmospheric temperature in the next 100 years. However, even that small amount will have a very noticeable effect. If the oceans warm by that amount they will expand, and the sea level will rise. If the water locked in the Greenland and Antarctic ice sheets melts and flows into the oceans, the sea level will rise by several feet. There are some places that cannot tolerate such a rise in sea level. The Republic of Maldives is a collection of islands in the Indian Ocean on average less than five feet above sea level. The state of Florida is not much better, and the city of New Orleans is right at sea level with some parts lower than the surface of the Gulf of Mexico just a few miles away.
Also, there is concern with runaway warming. If warming melts the northern snow belts, then the darkened landscape will absorb more heat from the sun, and warming will increase, causing more snow and ice to melt. It’s called positive feedback.
Again, none of this would be controversial, except that some people do not want to take responsibility for what we are all doing to contribute to global warming. People do not want to stop burning gasoline in their cars. They do not want to stop burning coal in their power plants. They want to cut down forests to plant annual crops. And so on.
So, what do people do? They do what people always do. They shoot the messenger who brings the bad news. It’s as though if the message goes away then the problem will go away. As with all problems there is a profit to be made solving the problem. Which brings us to the matter of Heartland Institute.
A quick trip to their home page reveals their message in a circulating marquee:
HEARTLAND FIGHTS BACK
Left-wing groups commit fraud, but we’re fighting back! Join our legal defense fund and remove false and defamatory materials and prosecute the true criminals.
The site also mentions a number of these “left-wing” groups:
NCSE (National Center for Science Education)
Greenpeace
Desmogblog
Huffington Post
Thinkprogress
Pacific Institute
Some of these groups I am familiar with, others not so much. The Huffington Post I read often, and I can swear to you it has a liberal slant. Also, let’s call Greenpeace a given, although I am not sure why. When did protecting the environment become a liberal idea? How come conservatives have not picked up on this and marched with it? This is what I sometimes wonder when I consider the original meaning of the word conservative.
The NCSE promotes the teaching of science-based concepts in public schools. What conservative organization would be against this idea? It’s possible that because creationism has become the foster child of conservative politicians the NCSE is now on Heartland’s radar. The NCSE has been for the past 30 years a champion of teaching the science of biological evolution, and this science is now targeted by conservative groups. The NCSE strongly opposes teaching creationism, including the story of Genesis and the modern Intelligent Design form, in public science classes. Let’s make matters even worse. Recently the NCSE put “global warming” denial alongside creationism as one of the pseudo sciences it will oppose.
A little reading of Thinkprogress gives the impression of a liberal attitude, and Desmogblog is obviously liberal due to its stance against climate science denial. That brings us to Pacific Institute.
Pacific Institute was founded by Peter Gleick, an American scientist specializing in environmental issues. More recently he stepped down as head of the organization after revealing he had obtained confidential documents from Heartland using a faked identity. He created a bogus Gmail account and sent e-mails to Heartland claiming they were from a named board member and asking that duplicate notices from Heartland be sent to the new address, as well. He received confidential documents from Heartland and released these documents to various outlets, including Desmogblog, which has posted them on the Internet.
Gleick has clearly stepped beyond the bounds of legitimate science and into the realm of advocacy. In addition to his disconnection from the Pacific Institute, the San Francisco Chronicle has dropped his on-line blog.
Gleick was apparently motivated to tap into Heartland materials by an anonymous correspondence he received containing a memo that Heartland now says was forged. Heartland acknowledges the other published documents obtained by Gleick but contends the forged document has harmed its reputation. They are threatening legal action.
It is impossible to reconcile Gleick’s actions as those of a serious scientist. Particularly his release of unsubstantiated evidence is outside accepted practice. Regarding the materials Gleick obtained from Heartland, it was not his job to do this kind of thing. This is best left up to others, such as Desmogblog and this blog. The Skeptical Analysis blog makes no claim for political neutrality, but there will always be an advocacy for real science and for doing the right thing.
I have reviewed the purloined materials, and I am happy to report they confirm what everybody knew all along. It brings me to wonder why Gleick went to all the trouble to expose the obvious. Did anybody think for a moment that Heartland has a legitimate agenda that caters to the public interest? Any difference between Heartland and a for-profit propaganda mill is difficult to discern. Here is part of an item posted on Desmogblog regarding the materials from Gleick:
We are releasing the entire trove of documents now to allow crowd-sourcing of the material. Here are a few quick highlights, stay tuned for much more.
Confirmation that Charles G. Koch Foundation is again funding Heartland Institute’s global warming disinformation campaign. [Update: Apparently even the Koch brothers think the Heartland Institute’s climate denial program is too toxic to fund. On Wednesday, Koch confirmed that it did not cut a check for the $200K mentioned in the strategy memo after all. A statement released on KochFacts.com and the charleskochfoundationfacts.org states that “…the Charles Koch Foundation provided $25,000 to the Heartland Institute in 2011 for research in healthcare, not climate change, and this was the first and only donation the Foundation made to the institute in more than a decade. The Foundation has made no further commitments of funding to Heartland.”]
The allusion is apparently to an item in Heartland’s 2012 fundraising plan. It shows an anticipated $25,000 expected for this year from Charles G. Koch Charitable Foundation. For those who do not watch the news, the Koch (coke) brothers are politically conservative billionaires whose family fortune originated with the petroleum industry.
Particularly telling is a Heartland memo titled “Confidential Memo: 2012 Heartland Climate Strategy” and dated January 2012. The contents appear to be no longer confidential, so a bit of disclosure is in order.
One paragraph speaks of the development of a “Global Warming Curriculum for K-12 Classrooms.” This is being developed by David Wojick, who has a long history of working for industrial organizations opposed to climate science. According to Sourcewatch, “He has a Ph.D. in philosophy of science and mathematical logic from the University of Pittsburgh, and a BS in civil engineering from Carnegie Tech. He has been on the faculty of Carnegie Mellon and the staffs of the US Office of Naval Research and the Naval Research Lab.” Also “Wojick has been described as a journalist and policy analyst. According to a search of 22,000 academic journals, Wojick has not published any research in a peer-reviewed journal on the subject of climate change.” The Heartland memo states that Wojick will be paid $100,000 to develop 20 educational modules with the funds coming from “The Anonymous Donor.”
The memo also states that Heartland funds “high-profile individuals who regularly and publicly counter the alarmist AGW message.” These include Craig Idso at $11,600 per month, Fred Singer at $5000 per month (plus expenses) and Robert Carter, at $1667 per month.
About Idso, Sourcewatch has this to say:
Craig D. Idso is Chairman, founder and former President of the Center for the Study of Carbon Dioxide and Global Change, a contrarian Arizona-based group funded in part by ExxonMobil. He is the son of its president, Sherwood B. Idso[1], and the brother of its vice president, Keith E. Idso.
According to Sourcewatch, Fred Singer “runs the Science and Environmental Policy Project (SEPP).., which publicizes his own views on various topics, primarily climate change, ozone depletion, risks of chemical pollution (from DDT and others), nuclear power, and space policy.” He has a long history of advocacy for concerns who have behaved badly in the public arena. Again from Sourcewatch:
In 1993, Singer collaborated with Tom Hockaday of Apco Associates to draft an article on “junk science” intended for publication. Apco Associates was the PR firm hired to organize and direct The Advancement of Sound Science Coalition for Philip Morris. Hockaday reported on his work with Singer to Ellen Merlo, Senior Vice President of Corporate Affairs at Philip Morris.
Sourcewatch has this to say about Robert Carter:
According to the Sydney Morning Herald in 2007, Carter was “on the research committee at the Institute of Public Affairs, a think tank that has received funding from oil and tobacco companies, and whose directors sit on the boards of companies in the fossil fuel sector” and believed, SMH said, that “the role of peer review in scientific literature was overstressed.”
If you have been reading along with me you have noticed one peculiar consistency. None of the people just mentioned are serious scientists working in the field of atmospheric science, environmental issues or any of the topics they are being paid to speak on. The word propaganda has a long history of various implications, but this case best illustrates the modern English usage.
When a dedicated cadre of serious scientists develops an idea that many in our society find objectionable, the only recourse for those who oppose this idea is to out-talk the scientists and call them liars and fools. The irony of this approach is that the accuser must take on the role of a liar or a fool. Another course of action would be to do real scientific research and develop opposing conclusions. The various industrial and political groups could take that route if they chose. Obviously they have not, and the reason they have not is because they cannot. If they could, they would. But they cannot, and they do not.
This is being reposted from the Skeptical Analysis blog. I used copy and paste, which may or may not work out so well.
We are considering a discussion of AGW (anthropogenic global warming) at the April meeting. Stay tuned for updates.
Billboards in Chicago paid for by The Heartland Institute along the inbound Eisenhower Expressway in Maywood, Illinois. Photograph: The Heartland Institute
We had a new candidate announce her campaign for the presidency yesterday. Later today we have another person announcing. But this is about politics and science:
GQ: How old do you think the Earth is?
Marco Rubio: I’m not a scientist, man.
We get that. But, is he a high school graduate? That question is likely to be on any high school science quiz in the nation. With the exception of some schools, of course.
So why is Senator Rubio pretending not to know the answer to this simple question? The answer, dear voters, is ourselves. A certain segment wants the government to confirm their basic religious myths. Answer the question incorrectly, and you don’t get their vote. You may not have to sell your soul to obtain public office, but your brain is up for grabs. At least your intellectual integrity.
There is no denying it: Climate-change deniers are in retreat.
What began as a subtle shift away from the claim that man-made global warming is not a threat to the planet has lately turned into a stampede. The latest attempt to deny denial comes from the conservative American Legislative Exchange Council, a powerful group that pushes for states to pass laws that are often drafted by industry. As my Post colleagues Tom Hamburger, Joby Warrick and Chris Mooney report, ALEC is not only insisting that it doesn’t deny climate change — it’s threatening to sue those who suggest otherwise.
Threatening to sue? Over what?
In 2013, ALEC planned legislation that would weaken state clean energy regulations and penalize homeowners who install their own solar panels and redistribute the electricity back into the grid, whom ALEC has described as “freeriders” because they do not pay for the infrastructure costs of recirculating their generated power.
Also in 2013, ALEC adopted a model bill saying that the role of human activity in causingclimate change was uncertain, that man-made climate change could be “deleterious, neutral or possibly beneficial,” and that the cost of regulating greenhouse gas emissions could cause “great economic dislocation.” ALEC has also invited climate change skeptics such as Craig Idso to speak at its national meetings. Environmentalist groups such as Common Cause and theLeague of Conservation Voters have pointed to such behavior to accuse ALEC of denying climate change. In 2015 ALEC wrote letters to these groups threatening legal action, denying that ALEC supports climate change denial, and saying it has more recently welcomed debate on the subject and supported renewable energy and carbon tax policies to curb global warming.
If ALEC won’t support global warming denial, then what use is it to its core principles—the promotion of short term gains at the expense of our future well being? With ALEC it has not been a matter of the truth being the first casualty. It’s a matter of the truth never being invited to the party. We have covered this before. Seventeen years ago we were getting the “kettle defense” from anti-environmentalists:
The neighbor offers his defense in three parts: 1) “I never borrowed the kettle.” 2) “It was already damaged when I got it.” 3) “It was in perfect condition when I returned it.”
That’s the essence of the “kettle defense” as explained in February 1998 issue of The North Texas Skeptic. This relates to the arguments of the anti-environmentalists:
Here’s another: 1) “There’s no way adding CO2 to the atmosphere will produce global warming.” 2) “Human activities are not adding enough CO2to the atmosphere to produce much global warming.” 3) “Natural sources are the cause of all this CO2.” 4) “Actually, more CO2in the atmosphere is helpful—it makes plants grow.” 5) “Hey, global warming will forestall the next ice age, which the climatologists were predicting earlier.” To this I might add a suggested 6) “I always wanted ocean front property in Orlando anyhow.”
A few Sunday’s ago I heard arguments 4 and 5 being advanced by an oil company executive on a news show. He sells products that routinely put a lot of CO2 into the atmosphere, and proposed remedies are going to change his company’s business drastically. He’s trying to make as many points as he can in case one of them can’t be supported. Actually, point 4 demonstrates he does have reason to worry. More recently, as seen on TV, a scientist studying an imminent volcano eruption in the Northwest was showing off a large section of forest killed off by CO2seeping from the ground. Not CO, not H2S, but CO2 is killing the trees.
Of course, there is a lot of silliness being advanced in the name of science these days, and it needs to be refuted by people who really know what they are talking about. I am glad to see every now and then knowledgeable people taking time off from their real jobs and standing in front of a camera explaining the facts and separating the wheat from the chaff. And they don’t have to use the kettle defense.
[As I write this it’s 62 degrees outside. Of course it’s January. At night.]
That last part was a dig at a previous item in the newsletter. The writer, no friend of the science behind global warming, had mentioned what cool weather we were experiencing. He liked to call people who deny environmental science “skeptics.” Here is an excerpt:
If you did not see the June 1 issue of Newsweek, please go to the library and catch up on it. The headline on the cover reads, “No More Hot Air: It’s Time To Talk Sense About The Environment.” Inside, there are several articles examining a variety of environmental controversies, all offering a rational, well-researched perspective that proved sadly absent from most of the speeches and reporting emanating from the Earth Summit.
One article in particular, “A House Of Cards” by Gregg Easterbrook, does an excellent job of explaining the problems with the “greenhouse effect” theory, and with making any long range predictions about world climate. Just a few examples…
Fifty years ago, England’s Royal Meteorological Society predicted that because of increased carbon dioxide emissions, a greenhouse effect had begun, and the Earth would heat irreversibly. Immediately, it got cooler.
After 30 years of cooler temperatures, environmentalists declared in the late 1970s that a new Ice Age was beginning. Immediately, it got hotter.
When the same global computer models that predict global warming are fed with climate information from the year 1880, they predict that temperatures should have risen five degrees by now. The actual increase is at most one degree, and this could be explained by variances in measuring standards and equipment.
There are many more such eye-opening facts throughout this issue of Newsweek, all of which added together show the difficulty of making any kind of accurate, longterm predictions about the weather. Indeed, a year or so ago, the Dallas Morning News interviewed meteorologists from local television stations, and all of them admitted that even their “five-day forecasts” are virtually worthless, and are only offered because of viewer demand. They’re like horoscopes … “presented for entertainment purposes only.”
Newsweek did an exemplary job of cutting through the political rhetoric that surrounds environmental issues, particularly “global warming.” The magazine probably surprised a lot of people who took it for granted that the doomsday scenarios were scientifically established. At the same time, the writers made clear the necessity for protecting the environment and the benefits that can come from taking immediate, rational action. Newsweek does not recommend clear-cutting the rain forests, even if you are building a meeting hall for environmentalist big-shots … they merely suggest cutting through the nonsense, so we know what really needs to be done and can begin doing it as soon as possible.
The alternative is the currently popular “Chicken Little” approach: the belief that it’s best to take some sort of radical action now, no matter what the cost or effectiveness, and even if it attacks a problem that doesn’t exist while ignoring worse problems that do. Like Leacock’s knight, we are urged to jump on our horse and ride off in all directions.
No thanks. Frankly, I believe that it isn’t the stuff you don’t know that can hurt you most … the most damage is done by the stuff that you know for a fact to be true, and which turns out to be wrong.
To be sure, some serious skeptics have voiced opposition to the science, notably James Randi and Penn Jillette. Then maybe not.
To heap ridicule on the anti-science crowd it’s only necessary to quote some of the extreme wack jobs.Here’s one:
In a recent interview with MSNBC, Rep. Jeff Miller (R-FL) argued that human activity can’t be causing climate change because there were no humans around when the dinosaurs went extinct.
“But then, why did the dinosaurs go extinct?” Miller asked. “Were there men that were causing – were there cars running around at that point that were causing global warming? No. The climate has changed since Earth was created.”
As I mentioned at the time, this is a slam dunk argument. There is no way to refute it.
Apparently ALEC is not alone in the retreat:
The turnabout at ALEC follows an about-face at the Heartland Institute, a libertarian outfit that embraces a description of it as “the world’s most prominent think tank promoting skepticism about man-made climate change.”
But on Christmas Eve, Justin Haskins, a blogger and editor at Heartland, penned an article for the conservative journal Human Events declaring: “The real debate is not whether man is, in some way, contributing to climate change; it’s true that the science is settled on that point in favor of the alarmists.”
Previously Heartland was less circumspect:
Development of our “Global Warming Curriculum for K-12 Classrooms” project.
Principals and teachers are heavily biased toward the alarmist perspective. To counter this we are considering launching an effort to develop alternative materials for K-12 classrooms. We are pursuing a proposal from Dr. David Wojick to produce a global warming curriculum for K-12 schools. Dr. Wojick is a consultant with the Office of Scientific and Technical Information at the U.S. Department of Energy in the area of information and communication science. His effort will focus on providing curriculum that shows that the topic of climate change is controversial and uncertain – two key points that are effective at dissuading teachers from teaching science. We tentatively plan to pay Dr. Wojick $100,000 for 20 modules in 2012, with funding pledged by the Anonymous Donor.
The image at the top of this page was provided by Heartland, and the billboard carries the Heartland endorsement. Much to Heartland’s dismay (we can only hope) there was broad and hilarious response:
I am sure Heartland did not put up these billboards. Or these:
It goes to remind that a hint of giggle is worth a ton of scorn.
All of this would be for nothing were there no real science behind claims for anthropogenic global warming. I once attempted to address this and posted a lengthy item titled The Heat Of Darkness. I’m going to repost the entire piece to the NTS site later today, but for now here are a couple of excerpts plus some graphics. Included three years ago was a snippet captured from Heartland’s site:
HEARTLAND FIGHTS BACK
Left-wing groups commit fraud, but we’re fighting back! Join our legal defense fund and remove false and defamatory materials and prosecute the true criminals.
The site also mentions a number of these “left-wing” groups:
NCSE (National Center for Science Education)
Greenpeace
Desmogblog
Huffington Post
Thinkprogress
Pacific Institute
Fortunately they did not mention The North Texas Skeptics, or we would have been in a world of hurt. Maybe the kind of hurt we seek out. The science part might make readers’ eyes glaze over, so to save you from having to read the entire explanation, here is the Schaum’s Outline version:
Keep this in mind. The Earth does not keep this energy forever. If it did, then the Earth would keep getting hotter and hotter until it melted, and we know that has not happened recently. When the surface of the Earth is warm it radiates invisible infra-red energy out into space. The hotter the surface becomes the more intensely it radiates energy. After a time the Earth’s surface reaches a temperature at which the combined reflected and radiated energy exactly equal the energy received from the sun. This is a system in equilibrium.
OK, that’s not strictly true. One problem we poor students had to solve was to calculate this average surface temperature. The solution was about 20 degrees F cooler than what we actually measure. What was wrong? What was wrong, and we knew this going in, is that the sun is not the sole source of heating for the Earth. The Earth contains within it a vast nuclear reactor, large quantities of uranium and thorium undergoing radioactive decay and releasing heat. Enough heat to keep the Earth’s average surface temperature where it is now. Which some would say is just about right.
Electromagnetic energy (including visible light and infra-red) must pass through the Earth’s atmosphere coming in and going out. The atmosphere intercepts some of that energy passing through in both directions. To get to the point, the Earth’s surface reflects some visible light and some infra-red, but it (mostly) only emits energy in the form of infra-red radiation. Without consulting any charts I am going to say a large amount of infra-red energy passes through the atmosphere on the way out into infinite space, never to return again. But some of this infra-red making the trip out gets absorbed by the atmosphere.
And here is a sample graphic:
This is all very complicated stuff, of course, and we can only hope that next year’s presidential contest does not devolve into a science quiz. If it does, some candidates are going to have to find a reverse gear.