Human Pollution Tipping Scales Toward More Weather Extremes

[xchrom]

http://www.scientificamerican.com/article.cfm?id=human-pollution-tipping-scaled-toward-more-weather-extremes

In the United States, 2011 was a year when weather seemed to ping-pong between extremes.

A historic drought struck Texas while floods devastated communities along the Missouri and Mississippi rivers and Hurricane Irene swamped the East Coast. Swarms of tornadoes rolled through the center of the country, and record-setting wildfires blazed in the Southwest.

But while 2011's litany of extreme weather was notable, it was "not unique" -- at least not in recent experience, according to a new analysis published yesterday in the journal Nature Climate Change.

The world has experienced an "exceptional number of unprecedented extreme weather events" for the past decade, say co-authors Dim Coumou and Stefan Rahmstorf, researchers at the Potsdam Institute for Climate Impact Research in Germany, who surveyed recent research linking climate change to shifts in the frequency and intensity of extreme weather.

[dixiegrrrrl]

1. We are 2 months ahead of spring,here, this week.

Normally the pecan trees are the last to leaf out, usually they do that in early May.
They are leafing out now.
The whole town is in full spring mode, practically overnight, as temps have hit the 80's and are forecast to continue that temperature.
Normally we have high 60's and low 70's in March.

[kestrel91316]

2. I don't track these things, but it seems like the crepe myrtles are

leafing out pretty early this year. I always used to notice them slow to do so - maybe May? But they began over a week ago.

[longship]

3. I'm very worried about arctic ice melt

There are two positive feedback mechanisms.

1. Reduction of albedo. Ice is more reflective than sea water which means that less ice means more heat absorbed by the seas, which means warmer seas, which means more global warming.

2. Arctic tundra methane. As the arctic gets warmer, the tundra is thawing and releasing frozen methane. This is already happening. The problem is that carbon dioxide as a greenhouse gas can't compare to methane. So the release of methane into the atmosphere is a second major positive feedback mechanism.

There are others, too. But these two could push the planet towards that tipping point where a run-away greenhouse on Earth could happen.

That's why funding for primary research in the sciences is essential. We need to know how these effects will change the planets climate.