Friday, August 04, 2006

Weather is not climate

It was a hot one on Monday and Tuesday here in Chicago--hot enough that I avoided getting a coffee to keep me warm in my cold office and opted for a iced drink. The heat wave affecting the Midwest finally broke and those in Chicago generally didn't do the following--

Those who can't remember the weather always say "It's never been so hot before". They tend to forget last year, or 1995, or 1988, etc. They tend to forget 1916, 1911, 1918. The entire Dust Bowl.

It's really important point: Weather is not climate. A heat wave is not the result of a change in climate. Weather is a day-to-day variation in temperature, humidity, etc. Climate is the long-term average of weather. On average, the climate of Chicago gives us 34 inches of water. On average. Look at the variation in yearly precipitation here. Even after averaging over 365 days, the average precipitation varies over +-10 inches of rain each year.

Look at the other graphs on the Chicago climate page.

The whole point is, you can't blame a single event, a single drought, a single year's weather on global warming. You can't. You can make statistical statements, but the natural variability of weather will mask any contribution by forced warming until you look at a long-term average (or some other greatly averaged variable).

Problematic web pages:
Treehugger: The Heatwave is On: Global Warming?
Bruce Sterling: Global Warming Knocks Out MySpace
Washington Post: More Frequent Heat Waves Linked to Global Warming

Someone took the research about reducing the well-known urban heat island effect and blame increasing nighttime temperatures on global warming, rather than accounting for the continued growth in urban areas.

Some comments here: Climate Science:Roger Pielke Sr. Research Group Weblog

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