The Truth about Averages

Michael Crichton is (update: or was, as I've been told) one of those people who doesn't really believe in catastrophic global warming or climate change. Based on a debate hosted by NPR during 2007, one of his big reasons is that if you just look at the numbers (mannn) then hey, it doesn't seem that bad.

And it's true (kinda). Since the start of the industrial revolution, when humanity's meddling with pollutants really started up on a huge scale, global temperature averages have grown by between one and three degrees (celsius). Sea level has risen between 100 and 200 millimeters (yes, American audience - the really small one).

Well dang, that's not very scary is it?

Here's the thing about averages: they don't give you the full picture all on their own. An average smooths everything out - but when it comes to weather and the climate, it's the extremes that really tell the story.

Take, for example, the more powerful hurricanes we've been seeing. Take the snow storm that hit the Pacific Northwest this winter. Take the trees that are dying because of warmer temperatures (post below).

Think about the last year. How do you remember weather? Did you average out the temperature of the whole year, or remember the sunny, hot summer days, the rain storm, the white Christmas?

The truth of the matter is that a small increase in average temperature makes a big difference. An average increase of about a single celsius degree has meant that the last 20 years have included 18 of the hottest years on record.

Now that's global warming.