Tuesday, July 13, 2010

Consequences: Heat

For the past several years, commentators have concentrated on various consequences of climate change, especially sea level rise. And there's been equally admirable attention to the chain of consequences and their interactions. All of this has been and will be necessary to scope the dimensions of crisis, especially those effects that aren't obviously connected. Last winter there also had to be discussion of counter-intuitive consequences, like more snow in certain places.

But oddly perhaps there's been little discussion of the most obvious consequence of global heating: heat. But with heat waves in the U.S. a new report from Stanford is very timely.

"Using a large suite of climate model experiments, we see a clear emergence of much more intense, hot conditions in the U.S. within the next three decades," said Noah Diffenbaugh, an assistant professor of environmental Earth system science at Stanford and the lead author of the study... Diffenbaugh concluded that hot temperature extremes could become frequent events in the U.S. by 2039, posing serious risks to agriculture and human health.

"In the next 30 years, we could see an increase in heat waves like the one now occurring in the eastern United States or the kind that swept across Europe in 2003 that caused tens of thousands of fatalities," said Diffenbaugh...

The study used two dozen climate models to calculate the likely rise in temperatures of approximately 2 degrees C. Applying their findings to powerful computer simulations for the future, the study found a heat waves equal to the most intense heat wave experienced between 1951 and 1999 is likely to occur five times between 2020 and 2029 in the western and central U.S. The decade after 2030 is likely to have at least seven such intense heat waves. Heats waves equal to the longest and worst are likely to happen three times in the eastern U.S.

"By the decade of the 2030s, we see persistent, drier conditions over most of the U.S.," Diffenbaugh said. "Not only will the atmosphere heat up from more greenhouse gases, but we also expect changes in the precipitation and soil moisture that are very similar to what we see in hot, dry periods historically. In our results for the U.S., these conditions amplify the effects of rising greenhouse gas concentrations."

Besides harming human health and agriculture, these hot, dry conditions could lead to more droughts and wildfires in the near future, he said. And many of these climate change impacts could occur within the next two decades – years before the planet is likely tor each the 2 C threshold targeted by some governments and climate experts, he added."

"The results were surprising," the Stanford University News story said, though it's not clear who was surprised. These findings are consistent with others, including the UN climate panel reports. They suggest that at minimum the beginning of the transition from Climate Crisis to Climate Cataclysm at mid century.

But in the real felt context they also suggest the consequences, viscerally. There is a new book on air-conditioning that appears to be the beginning of a discussion that will become more and more pertinent. My own vivid recollections of severe heat waves in Pittsburgh suggest the range of difficulties. My life became a quest for air conditioning. I had one room air conditioner that I moved from bedroom to office and back. On the worst days, I spent as much time as I could in air conditioned public areas--restaurants, movie theatres. It was often too cold, but that was better than the literally suffocating heat.

Air conditioning requires electrical power, which currently contributes to the greenhouse gas pollution that creates future heat waves. It's a causal feedback loop, otherwise known as a vicious circle. This is one issue that is better faced when cooler heads can prevail, and not because they are the elite that can afford air conditioning.

There are consequences in where people live as well as how. All of this lies within the lifetimes of many alive today. Not to mention what's going on right now. (Make that right right now.) Fortunately some people have been thinking about these problems and devising solutions. But so far, there is not the public will or atmosphere to beginning dealing with these problems before everyone gets too hot under the collar to think straight. If on some other level we haven't already passed that tipping point already.

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