Who will stop/start the rain?

Media outlets both main and sidestream are abuzz (atwitter?) with the story that scientists are finally daring to link specific weather events with anthropogenic climate change. A pair of papers in Nature are to blame. One, Human contribution to more-intense precipitation extremes, concludes that the titular events “have contributed to the observed intensification of heavy precipitation events found over approximately two-thirds of data-covered parts of Northern Hemisphere land areas.” The other manages to summarize the whole thing in its tile: “Anthropogenic greenhouse gas contribution to flood risk in England and Wales in autumn 2000.”

This is all very interesting, as it will almost certainly help convince European holdouts that the effects of rising concentrations of greenhouse gases are not just a problem for our children’s children, but something that could sway elections results today.

For U.S. audiences, though, I’d like to point out that something that most coverage so far hasn’t had room or time to mention: increased snow and rain are possible effects for only some regions. Others will experience the opposite. While the smaller the region at question the more uncertainty there is, most predictions for the southwest, for example, call for drier conditions. Residents of Phoenix and Las Vegas should keep this in mind when they think about their long-term future.

The same is true on the other side of the planet. Northern Chinese farmers, in particular, are having a rough time dealing with the lack of rain:

Last week, the United Nations Food and Agriculture Organization issued a rare “special alert,” warning that the ongoing drought that has hit the provinces of Shandong, Henan, Hebei, Jiangsu and Shanxi – which together account for nearly two-thirds of China’s wheat production – has already jeopardized crop yields and “could become critical” if the dry spell stretches into spring. The state-run Xinhua newswire has referred to the drought in Shandong as the worst in two centuries.

“In my hometown area, everything depends on nature. We don’t have wells or other irrigation, so if there is no rain there is no water in the fields. Planting time comes in one month. If there is still no rain by then, the whole year is lost,” said Wang Guichun, a Shandong native selling flour Wednesday in a wholesale food market on the western edge of Beijing. (Globe and Mail, Feb. 17, 2011)

The implications of which make the prospect for increased precipitation in Europe seem like a petty annoyance by comparison:

China is grappling with drought just as food prices here and in many parts of the world are soaring, creating concerns that unrest could spread as poor countries find many items unaffordable. Broader inflation is also a rising worry in China and other fast-growing emerging markets, and a problem in some slow-growth countries such as the United Kingdom. Rising prices for an array of goods could destabilize global economic recovery as companies cope with higher costs and central banks around the world feel mounting pressure to raise interest rates and slow growth.

(Did someone mention Egypt?)

The two Nature studies make for fascinating reading, though. I was most intrigued to learn that one of them — the analysis of storms of England and Wales — was only made feasible through the use of the distributed computing network climateprediction.net. Tens of thousands of otherwise idle home and business computers turned what would have been a years-long task that is “beyond available conventional supercomputing resources” into something that more manageable.

Trust Gavin at Real Climate to say something useful on this point:

… while questions about attribution related to flooding come up whenever something weird happens to the weather, these papers demonstrate clearly that the instant pop-attributions we are always being asked for are just not very sensible. It takes an enormous amount of work to do these kinds of tests, and they just can’t be done instantly. As they are done more often though, we will develop a better sense for the kinds of events that we can say something about, and those we can’t.

Even distributed computing won’t help climatologists answer such questions in time for a reporter’s next deadline. But computers are getting faster and networks bigger every day. Go citizen scientists.

3 Replies to “Who will stop/start the rain?”

  1. James – we should send any doubters to Thailand and see for themselves the anthropogenic effects firsthand. Having just returned from there (what an amazing month!) one can easily see the differences between Bangkok (a large city of 5.7 million) and Chiang Mai (only 143,000). In Bangkok, the taxis and tuk-tuks (those three-wheeled powered rickshaws) run on LPG; in Chiang Mai, all seem to run on gasoline. I was chocking and sneezing there (as were the residents), while I was relatively comfortable in Bangkok. While this is not a true display of our effects on climate, it does demonstrate how we influence local environments. BTW in Bangkok, even the “cleaner” air generated smog in such quantities that I mistook the bleak clouds for impending rainstorms.

  2. How kind of Johnny to auto-summarise his contribution so we don’t have to wade through paragraphs of it.

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