Stormy weather: we’re making it worse, and there’s more on the way

By Gareth Renowden 20/11/2011

The IPCC released the summary for policymakers of its Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX) in Kampala, Uganda, on Friday (SPM, SREX site, launch presentation slides). The report concludes that globally there has been a significant decrease in cold days and nights and an overall increase in warm days and nights, that it’s likely that “anthropogenic influences” have led to warming of extreme daily minimum and maximum temperatures, and that heavy rainfall events are increasing in many areas. There has also been an increase in extreme coastal high water events.

The report also projects that it is “virtually certain” that increases in the frequency and magnitude of warm daily temperature extremes will continue through this century, and that there will be corresponding decreases in cold extremes. It’s also very likely that heat waves and warm spells will become more frequent and warmer. Heavy rainfall events are also expected to increase, and the proportion of rain falling in those events is likely to increase. There are also likely to be more problems from storm surges and sea level rises, an increase in droughts, and landslides in mountainous regions.

Much of the report’s content will come as little surprise to those who have been following the subject — in common with previous IPCC reports the conclusions are conservative, couched in laboriously exact language, and exclude the most recent work1 — and for me the most interesting parts are the discussions of how extreme weather events interact with human populations to create disasters. In this respect, arguing about whether an event was “caused by” or “made worse by” warming is largely irrelevant to trying to find ways to reduce the impact of current and future extremes.

See also: Jeff Masters has an interesting post going into more detail about the report’s findings, RealClimate considers the report’s discussion of tropical cyclones, plus news reporting from the BBC, Guardian, and Reuters.

Meanwhile, the usual suspects are scrabbling around looking for ways to misrepresent the report’s findings. The most egregious to date comes from Nigel Lawson’s secretly-funded “Global Warming Policy Foundation”, who pick a paragraph out of context and pretend that it shows that…

According to a preliminary report released by the IPCC, there will be no detectable influence of mankind’s influence on the Earth’s weather systems for at least thirty years, and possibly not until the end of this century.

… which is not what the report says at all!

Finally, Green.TV and WeatherUnderground have launched a new twice monthly video on current global extreme weather events. Here’s the first episode:

Definitely one to follow with interest…

  1. Unavoidable, given the way these things are put together.