LJWorld.com weblogs Global Warming from a Conceptual Standpoint
Where We Are Going
It has been a while since climate change was an active discussion here. I suppose people in general are more concerned about their welfare in the short term (and hence a focus on the economy) than they are about their welfare in the long term. Or, perhaps it has become too much of a polarized issue, and people avoid talking about it in polite company. In any event, it is not the case that the laws of physics have been put on hold while we try to fix our economy. I came across a post on Skeptical Science, and I thought, what the heck, I'll go there. Below is my comment on that topic, with some additional content at the end.
Let's imagine that the leading industrial nations, China, the U.S., Germany (God bless you for your self-imposed limits to growth (gaseous fuels at least) so far.), etc., decide this year to take aggressive action to shift off of fossil fuels. How long would that take without wrecking their economies, which we can assume they are unwilling to do?
I'll ballpark 2-3 decades to shift the energy infrastructure to a new paradigm. Let's assume that these leading industrials influence others to follow suit, and so we can map global emissions along the same path. As a rough estimate, we can say that for this approximately 25 years, emissions will be half of what they are now. (Just figure a steady decline from where we are now to zero.) Currently, we are increasing CO2 ppm at a rate very close to 2ppm / year, and in context. So, assuming action this year, halved CO2 output, over 25 years, leads to a ballpark of 425 CO2 ppmv by the time we could level it off, even given a strong desire to do so.
Climate sensitivity estimates are narrowing in more and more toward about 3 degrees C per doubling of CO2, based on both models and paleoclimate studies. Another source for this estimate is here, complete with about 30 peer-reviewed references.
That amount of CO2 puts us close enough to 2 degrees C of warming to make me nervous, and does not factor in any feedbacks, like melting permafrost or destabilized clathrates.
Judging by the lack of any real progress at any of the recent climate change talks, it will be some more years before we get serious about reducing CO2 emissions. So, we are likely going to hit 2 C warming, plus whatever feedbacks ensue. I'm not trying to give credence to those that say there is no point in attempting mitigation, because it is not the case that 2 C of warming will be as bad as 3 C, or 4 C, etc.
Since agriculture is a major business here in Kansas, let's talk about what is expected to happen here. Hadley cells largely determine where rain falls. (Feel free to Google up your own reading on Hadley cells and how they have already started shifting.) In addition to climate zones shifting toward generally warmer conditions, rain patterns are shifting poleward. Roughly, Texas is becoming more like northern Mexico was, Oklahoma is becoming more like Texas, and Kansas is becoming more like Oklahoma, and so on. Regardless of what some say about a warmer climate being beneficial, I don't see this as being a positive development. A drier, hotter climate will lead to more demands on an irrigation aquifer already being depleted. I have to figure that will mean it will be more difficult to make a living by farming in Kansas.
As a side note: I have an idea; let's put up a coal plant in western Kansas that will not only contribute to a degradation of our ability to produce food, but will directly compete with agriculture for water in a drying environment. Oh, but we need the electricity, never mind that most of it has already been guaranteed to go to Colorado.