Wednesday, August 29, 2012

Climate Moving at One Foot Per Hour

Ken Caldiera has a great article in the September issue of Scientific American -- "The Great Climate Experiment" -- that takes a longer view of climate change, past 2100, over millenia and longer (hectomillenia?).

He puts it all out simple and plain, with neither alarming nor solace. For example, he writes "The outlook may be for increased crop productivity overall, with increases in the north exceeding the reductions over the equator. Global warming may not decrease overall food supply, but it may give more to the rich and less to the poor."

He notes that in the northern midlatitudes (30°N to 60°N), the annual average temperature drops about 2/3rds of a degree C with each degree of increasing latitude.
"With five degrees of warming in a century, that translates into an average poleward movement of more than 800 kilometers in that period, for an average poleward movement of temperature bands exceeding 20 meters each day. Squirrels may be able to keep up with this rate, but oak trees and earthworms have difficulty moving that fast." 
Over the last 20 years, GISS's northern hemisphere temperature has increased at a rate of 0.27°C/decade. Let's exclude the equatorial region and call it 0.2°C/decade. That implies a current rate of climate shift of over one foot each hour. Over 6 millimeters a minute. 2.1 miles a year.

You should read his article, even if you have to buy the issue, a special one themed "Beyond the Limits of Science," for your tablet or off the newstand.

4 comments:

Survival Acres said...

I wonder if he accounted for the poor soils in the North. I haven't read his work.

The claim that we're going to be able to move our cultivation efforts northward, and even exceed what we're losing in the equatorial regions, must take into account the rather poor soils farther north which do not have the same capacity as what we have today.

There was a study I read that indicated that this simply will not happen, but I don't have it handy right now (sorry), maybe somebody else will remember it.

Also, the light is different farther north (shorter seasons). Living far north in the US myself, I'm keenly aware of how I must time my garden efforts.

And there is the loss of 100,000 square kilometers of ice per day being lost in the Arctic now, (a truly staggering figure), the march northward may speed up quite dramatically.

And the amplitude increase we're seeing in the jet stream and the 'lingering' effects will dry out soils longer and faster.

Dano said...

The claim that we're going to be able to move our cultivation efforts northward, and even exceed what we're losing in the equatorial regions, must take into account the rather poor soils farther north which do not have the same capacity as what we have today.

Yes, exactly. None of the people who want to do nothing to mitigate want to hear that inconvenient fact.

Best,

D

David Appell said...

If you recall that study, I'd be interested in it....

In what way are more northern soils (US upper midwest, Canada, Russia, etc) poorer than in the mid-latitudes?

Dano said...

In what way are more northern soils (US upper midwest, Canada, Russia, etc) poorer than in the mid-latitudes?

They have less chemical and biological activity due to the shorter growing season. In general, mesic soils are the most productive (e.g., Great Plains before man ruined them).

Best,

D