Re: A clean planet

From: Mike Maxwell (maxwell_at_ldc.upenn.edu)
Date: 09/23/04 

Date: Thu, 23 Sep 2004 09:27:14 -0400

I have no idea whether increased CO2 will lead to increased plant growth
in general, and increased food production in specific, nor do I want to
get into that topic, or whether global warming is happening or not, nor
whether (or to what extent) it's caused by humans. But...

Aidan Karley wrote:
> The claim that CO2 increases will lead to overall increase in
> food production is not well founded. For some individual crops the
> yield does increase in situations of elevated food production, but if
> those crops can't be grown in the areas that currently grow them due to
> the climate change that goes with the increased CO2 levels, then will
> overall production increase?

Why not grow them in areas that _DON'T_ currently grow them? Like
(further north in) Canada, or Siberia? Nice long days in the growing
season, too...

> That some of the most productive areas of ground in the world
> are close to becoming desert should be obvious from a study of recent
> American history. Read up on the "Dust Bowl" while you think about that
> (actually there were 3 or more separate bowls, but that's a sideline).

Perhaps you missed the articles that appeared a few days ago, based on a
study published by Zaitao Pan (Saint Louis University) et al in
Geophysical Research Letters. Here's an excerpt (taken from
http://www.physorg.com/news1263.html):

> Ray Arritt, agronomy professor at ISU, said the existence
> of this “hole” in the warming makes sense.
>
> “Our model tells us the future climate will have more
> rainfall and wetter soil, so more of the sun’s energy
> goes into evaporating water than heating the air,” he said.
> “Rainfall in the northern Great Plains already has increased
> by about 10 percent over the past few decades, which is
> consistent with our predictions.”

Whether they happen to be right about the dust bowl area becoming
wetter, and whether that trend will continue, is beside the point.
Global warming does not necesssarily mean desertification everywhere.

    Mike McSwell