Head in a Cloud

troposphere and stratosphere meet blogosphere

Head in a Cloud random header image

One Flew Over the Cuckoo’s Nest

February 27th, 2007 by Sean Davis · No Comments

So I received a call from my father in Tulsa, OK, a few weeks ago, and he starts by saying “Hey Sean, What’s your friend Lars’ last name?”. I tell him and ask him why, and he says “Oh. Good. Some quack (not the actualy word he used) named Lars from Boulder (not actually my friend. whew.) wrote a long letter to the editor about how the science of global warming is wrong. This is all a bunch of jibberish to me, but I’ll have to send it to you”. I laughed. A week later, I received a cutout of this letter [Update 3/14: A scan of the actual letter he sent in to UTW can be found here] from the “Urban Tulsa Weekly” in the mail, and was somewhat depressed and ticked off by the fact that something this nutty could have appeared in a widely read publication.

If you don’t have time to read this letter, it basically says that there is no greenhouse effect on Earth. Ha!

Now, I know that the “mission statement” of this blog is not to become entangled in the climate wars, but this letter pissed me off so much that I felt like I couldn’t not respond to it. So I did. And not the least because I have the feeling that in Tulsa, an article like that would go completely unchallenged. Am I getting sucked into the trap of the climate wars by doing this? I hope not…

I guess it all comes down to how you define the climate wars… If you are talking about correcting gross misrepresentations of really basic science, then yes, I guess I’ve jumped headlong into the climate wars. But if one defines the climate wars in a Roger Pielke, Jr.’in kind of way — that is, debating climate science (on either side) as a front for promoting a pre-determined set of values/policy outcomes — then I would like to think that I have somehow stayed above the fray.

Here’s my response to the letter, which was published in the Urban Tulsa Weekly. You can decide whether I wasted my time or inadvertently conferred legitimacy to a quackpot by responding.

Dear Editor,

This letter is in response to the letter “More Science on Global Warming”, by Lars Wahlin. Mr. Wahlin’s letter exhibits complete ignorance of the basic balance of energy in Earth’s climate system, and makes a completely irrelevant point that has no bearing on the debate over what to do (or not do) about global climate change.

Mr. Wahlin’s point goes something like this: (1) Because this figure (reproduced below) appears to violate a fundamental physical law – that energy can neither be created or destroyed (it can only change forms, like when the potential energy of a taut bow is converted to the kinetic energy of an arrow when the bow string is released) – then (2) the science of global warming (and in Mr. Whalin’s view, presumably any action to mitigate it) must be “a hoax”, to use Senator Inhofe’s own words.

The problem with part 1 of this argument is Mr. Wahlin’s incorrect interpretation of the conservation of energy in the context of this graph. Mr. Wahlin compares the amount of energy coming into Earth from the Sun (342 W m-2 in the figure) with the amount emitted by the surface (390 W m-2). He states that the fact that these are not the same somehow disproves the existence of a greenhouse effect. This is complete and utter nonsense.

To understand why, we need to think about what this graph is actually showing. This graph depicts the amount of energy coming into and going out of the Earth’s climate system. On average, the amount of energy entering the Earth at the top of the atmosphere (from the Sun) must equal the amount of energy leaving the Earth (again, from the top of the atmosphere, NOT the surface). If we look at the arrows in this figure and compare what is coming down into the Earth (342 W m-2), we see that it is exactly balanced by what is leaving Earth at the top of the atmosphere (For those who are not mathematically inclined, the arrows pointing up are 107 W m-2 + 235 W m-2 = 342 W m-2).

The same goes for the surface of the Earth. The 390 W m-2 emitted by the surface, as well as all of the other things coming out of the surface, must (and do!) equal what is going in to the surface (you can do the math yourself on this one). So, to put it succinctly, there is NO violation of any physical law that is taking place here.

With regard to the sencond point above: Except for the occasional deceived or deceiving person such as Mr. Wahlin (I’m not sure which one he is), no one — not even Senator Inhofe or any of the so-called “climate skeptics” — disputes that a greenhouse effect exists on Earth. Not only does the greenhouse effect exist, it is responsible for the hospitable temperatures we enjoy (well, the temperatures in summer in Tulsa aren’t exactly hospitable — but that’s an entirely different story). Other planets such as Mars (no greenhouse effect) or Venus (super greenhouse effect) stand in stark contrast to Earth and show us how truly lucky we are to have a greenhouse effect.

So the question is not whether or not a greenhouse effect exists, but how much we are altering its strength (or, more precisely, the global energy balance) by our experiment on the atmosphere via our emissions of gasses such as the carbon dioxide and methane. This question has been studied extensively in recent decades, and the results are summarized in the recent Intergovernmental Panel on Climate Change’s (IPCC) report which states that “Most of the observed increase in globally averaged surface temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations” (document available at http://www.ipcc.ch/SPM2feb07.pdf ). In the parlance of the IPCC’s wonky policy language, the term very likely means that they are 90% confident that most of the recent warming is due to human activities.

And again, here, there is no meaningful dispute over what the science says on this issue. From scores of science academies all over the world (National Academy of Sciences, American Geophysical Union, and the American Meteorological Society, to name a few), to President George W. Bush, nobody disputes the conclusions of the IPCC regarding the state of knowledge about the climate system and the human impact thereon.

And this brings us to the real crux of the “climate problem”. The problem is not whether or not the greenhouse effect exists, or whether the Earth is warming, or whether humans are contributing to that warming: It’s a matter of what do we do or not do in the face of a very high confidence that human activities are warming the planet. And this “climate problem” is a mostly non-scientific issue. It has to do with our values and not the science of climate change. Values of all sorts – political, religious, social, and economic – will affect what actions or inactions we might consider in the face of the uncertainty inherent in any decision making process. As scientists, we have done almost all we can to provide answers to the questions about what has happened to Earth’s climate, and what will likely happen given different possibilities for future greenhouse gas emissions. It is up to you the greater public, and policymakers, to decide how to proceed from here. The ball is in your court.

Sincerely,

Sean Davis

Tulsa Native

Ph.D. Candidate

Laboratory for Atmospheric and Space Physics

University of Colorado

Boulder, CO

earthsenergybalance.png

Tags: climate · general interest · global warming

0 responses so far ↓

  • There are no comments yet...Kick things off by filling out the form below.

Leave a Comment

*