The Greenhouse Gas Effect All-Star Fan Club
Posted on 5 December 2012 by Daniel Bailey
The greenhouse effect is standard physics and confirmed by observations. We only have to look to our moon for evidence of what the Earth might be like without an atmosphere that sustained the greenhouse effect. While the moon’s surface reaches 130 degrees C in direct sunlight at the equator (266 degrees F), when the sun ‘goes down’ on the moon, the temperature drops almost immediately, and plunges in several hours down to minus 110 degrees C (-166F).
Since the moon is virtually the same distance from the sun as we are, it is reasonable to ask why at night the Earth doesn’t get as cold as the moon. The answer is that, unlike the Earth, the moon has no water vapour or other greenhouse gases, because of course it has no atmosphere at all. Without our protective atmosphere and the greenhouse effect, the Earth would be as barren as our lifeless moon; without the heat trapped overnight in the atmosphere (and in the ground and oceans) our nights would be so cold that few plants or animals could survive even a single one.
The most conclusive evidence for the greenhouse effect – and the role CO2 plays – can be seen in data from the surface and from satellites. By comparing the Sun’s heat reaching the Earth with the heat leaving it, we can see that less long-wave radiation (heat) is leaving than arriving (and since the 1970s, less and less radiation is leaving the Earth, as CO2 and equivalents build up). Since all radiation is measured by its wavelength, we can also see that the frequencies being trapped in the atmosphere are the same frequencies absorbed by greenhouse gases.
Disputing that the greenhouse effect is real is to attempt to discredit centuries of science, laws of physics and direct observation. Without the greenhouse effect, we would not even be here to argue about it.
Don't believe me? Here's some testimony from the side of the "skeptics" (a veritable "baker's dozen" Who's-Who):
The GHG Effect All-Star Fan Club Membership
"Is there a greenhouse effect? Concedo [concedo / concede]. Does it warm the Earth? Concedo. Is carbon dioxide a greenhouse gas? Concedo. If carbon dioxide be added to the atmosphere, will warming result? Concedo."
"I am delighted that this simple and clear but authoritative statement of the reality of the “greenhouse effect” has been posted here. Too many inaccurate statements to the effect that there is no greenhouse effect have been published recently, and they do not deserve to be given any credence. The true debate in the scientific community is not about whether there is a greenhouse effect (there is), nor about whether additional atmospheric CO2 causes warming (it does), nor about whether CO2 concentration is rising (it is), nor about whether we are the cause (we are), but about how fast CO2 concentration will rise (for a decade it has been rising at a merely-linear 2 ppmv/year, against the IPCC’s projection of an exponential increase at today’s emission rates), how much warming a given increase in CO2 concentration will be expected to cause (around a third of what the IPCC projects), whether attempting to mitigate future “global warming” will make any real difference to the climate (it won’t: remember Canute), whether the cost of forestalling each degree of “global warming” will be disproportionate to the climatic benefit (it will), and whether focused adaptation to any change in the climate, where and if necessary, will be orders of magnitude cheaper than trying to prevent that change from occurring in the first place (yes)."
"infrared-absorbing gases warm the surface and lower atmosphere"
"I have not yet seen any compelling evidence that there exists a major flaw in the theory explaining the basic operation of the Earth’s natural Greenhouse Effect."
"Imagine you find yourself lost in outer space, floating aimlessly, with your warm skin exposed to the cold background of the cosmos. Sure, keep your clothes on. There is no sun or nearby stars to add much energy to your body. Your skin would gradually cool by losing IR radiation. (Of course, if the lack of air didn’t kill you first, you would freeze to death. Bear with me here…)
But now imagine you then surround yourself with a blanket. We won’t even use a fancy, NASA-invented, IR-reflective “space blanket”…just a woolen one. And let’s even assume the temperature of the woolen blanket was extremely low — just above absolute zero. Some of the IR radiation you emit, instead of being lost to the depths of space, would then be intercepted by the blanket. This would raise the temperature of the blanket. As that happened, the inside of the blanket would begin to emit some IR energy back toward your body, while the outside of the blanket would emit energy to outer space.
As a result, the temperature of your skin would remain higher than it would without the blanket — even though the blanket would remain at a lower temperature than your skin. So, contrary to what some would intuitively expect, the introduction of a cold object has made a warm object warmer than it would have otherwise been.
But it didn’t actually RAISE the temperature of your skin. In this example, all we have done is slow the rate of cooling of your body, and you would eventually freeze to death anyway. But if you had a continuous supply of energy available (like the Earth does with the sun), and had reached a steady state of shivering and discomfort and THEN added the blanket, your skin would indeed increase its temperature, compared to if the (colder) blanket was not there.
Of course, this example is just an analog to the Earth in space. The Earth has an energy source (the sun), and it has a “radiative blanket” (greenhouse gases) enveloping it.""
"There is a greenhouse effect"
"The emission of CO2 into the atmosphere, and its continued accumulation in the atmosphere is changing the climate. We do not need to agree on the magnitude of its global average radiative forcing to see a need to limit this accumulation. The biogeochemical effect of added CO2 by itself is a concern as we do not know its consequences. At the very least, ecosystem function will change resulting in biodiversity changes as different species react differently to higher CO2. The prudent path, therefore, is to limit how much we change our atmosphere."
"One of [deniers'] favorite arguments is that the greenhouse effect does not exist at all because it violates the Second Law of Thermodynamics...One can show them data of downwelling infrared radiation from CO2, water vapor, and clouds, which clearly impinge on the surface. But their minds are closed to any such evidence."
"Another subgroup simply says that the concentration of atmospheric CO2 is so small that they can't see how it could possibly change global temperature. But laboratory data show that CO2 absorbs IR radiation very strongly."
6. Jo Nova
"Technically, strictly, greenhouse gases don’t “warm” the planet (as in, they don’t supply additional heat energy) but they slow the cooling, which for all pragmatic purposes leaves the planet warmer that it would have been without them. It’s a bit like saying a blanket doesn’t warm you in bed. Sure, it’s got no internal heat source, and it won’t add any heat energy that you didn’t already have, but you sure feel cold without one. Instead of calling it “global warming”, I guess they could have called it “less-global-cooling”. I can’t see it catching on."
"The serious skeptical scientists have always agreed with the government climate scientists about the direct effect of CO2. "
"carbon dioxide is a thermal gas so it will cause warming to some extent...that's one about which there really is a consensus about [with] most people."
"The greenhouse effect is real, as is the enhancement due to increasing carbon dioxide concentration."
10. Richard Tol
"The enhanced greenhouse effect is a plausible explanation for the observed global warming. Long term natural variability is another prime candidate for explaining the temperature rise of the last century. Analysis of natural variability from paleo-reconstructions, however, shows that human activity is so much more likely an explanation that the earlier conclusion is not refuted. But, even if one believes in large natural climatic variability, the odds are invariably in favour of the enhanced greenhouse effect."
11. Judith Curry
"Tyndall proved in 1861 that both water vapor and CO2 were greenhouse gases."
"It's hardly news that human beings have had a hand in the planetary warming that began more than 30 years ago. For nearlly a century, scientists have known that increasing atmospheric carbon dioxide would eventually result in warming that was most pronounced in winter, expecially on winter's coldest days, and a cooling of the stratosphere. All of these have been observed."
"Pretty much every serious student of climate change agrees that carbon dioxide, which is the product of the respiration of our civilization, is a "greenhouse gas." Everything else being equal (which never holds), increasing its concentration should result in some rise in temperature in the lower atmosphere."
13. Anthony Watts
"I suppose that because I agreed that global warming occurred over the last century, and that CO2 plays a role (though isn't the only driver) that he [Spencer Michels, PBS Newshour correspondent] was surprised that he didn't have a "denier" soundbite to work with."
"I'm saying that the data might be biased by these influences [urbanization's buildings and streets] to a percentage. Yes, we have some global warming, it's clear the temperature has gone up in the last 100 years. But what percentage of that is from carbon dioxide? And what percentage of that is from changes in the local and measurement environment?"
For any remaining hold-outs, Skeptical Science answers the most commmon objections that have been used by skeptics in opposition to basic GHG theory. Of more general interest, the history of climate science is largely the history of what we've learned about CO2.
Science of Doom (Warning: for readers who enjoyed physics class)
- http://scienceofdoom.com/roadmap/co2/ (8-part series)
- http://scienceofdoom.com/roadmap/atmospheric-radiation-and-the-greenhouse-effect/ (12-part series)