Climate Momentum

In my very first post to this blog, I described how changing the course of global warming and its effects is like turning a large, heavy, fast moving ship. You have to begin the turn way before you want the ship to be headed in the new direction, and if you wait too long, you won’t make the turn in time. Another way of saying this is that global warming has a lot of momentum. Scientists at Sustainability Institute, Ventana Systems, and MIT developed an online tool where you can see how different emissions reduction scenarios will affect CO2 levels, temperature, and sea level. Move the slider at the bottom of the charts to change the emission reduction scenario. This gives a clear demonstration how strong global warming momentum is.

http://www.bgrncol.com/

I wish the charts went past 2100, because the effects will continue for much longer, and I wish I had more control, such as to be able to duplicate the Waxman-Markey bill. But even only showing this much, it is clear that even if we reduce emissions around 50% by 2020 and 80% by 2050 (much more than the Waxman-Markey bill does in the short term, slightly less in the long term), the temperature will reach 2 degrees above preindustrial levels by 2080 and continue to rise after that. In fact, in order to limit temperature rise to around 2 degrees by 2100, we would have to reduce emissions 95% by 2020! Compare that to the 3.6% reduction by 2020 in the Waxman-Markey bill, and you will get an idea of how divorced from reality Congress is. Even the more realistic governments of Europe are only planning to reduce emissions 20% by 2020.

An even scarier thing this tool shows is that if all countries follow their most recent (March 2009) “publicly stated proposals” for CO2 emissions reductions, temperatures will reach almost 4 degrees above preindustrial levels by 2100, and from the shape of the curve, it looks to me like they will probably rise another couple of degrees after that. So if countries do what they say, we are set to experience the worse scenarios laid out in “Six Degrees”. It is even more depressing to realize that so far countries as a whole have not even done what they promised in the past.

And apparently, the models these charts are based on do not take the various feedbacks into account, because if they did, the temperatures should rise more sharply after reaching about 3 degrees, even if emissions are falling by then.

Even with the best case scenario these charts show, which I don’t think the world will come close to achieving, we are just barely able to keep temperatures to a roughly 2 degree rise. James Hansen said this to Congress in 2008: “The disturbing conclusion, documented in a paper I have written with several of the world’s leading climate experts, is that the safe level of atmospheric carbon dioxide is no more than 350 ppm (parts per million) and it may be less. Carbon dioxide amount is already 385 ppm and rising about 2 ppm per year. Stunning corollary: the oft-stated goal to keep global warming less than two degrees Celsius (3.6 degrees Fahrenheit) is a recipe for global disaster, not salvation.”

If you want to see the paper he refers to in this quote, go to the links below. The top one is the paper, and the second one is supporting material for the paper.

http://arxiv.org/ftp/arxiv/papers/0804/0804.1126.pdf

http://arxiv.org/ftp/arxiv/papers/0804/0804.1135.pdf

Many months ago, I had a feeling from everything I had read and the trends I had seen that we probably would not be able to avoid global disasters caused by global warming. Unfortunately it looks like that feeling was correct. But now it even looks extremely likely that feedback will take over, probably leading to the next great extinction. This does not mean we should give up, it means we should fight harder, as if our very lives depended on it. If we do, we still might be able to prevent another great extinction, caused by us this time. If we don’t, I guess our children and grandchildren will get what we deserve.