Farmers' crops keeping US cool

[OKIsItJustMe]

http://www.newscientist.com/article/dn17079-farmers-crops-keeping-us-cool.html

Farmers' crops keeping US cool

Updated 13:24 07 May 2009 by Catherine Brahic

While cities create a warm bubble known as the urban heat island, most farms have an opposite chilling effect. This "cool farms factor" has lessened the effects of global warming across the entire continental US, and could continue to do so, suggests new research.

It also suggests projects that plant trees to cool the planet need to be approached with caution.

Fields can lower temperatures in two ways: by using solar energy to evaporate water – in a similar way to a person cooling down by sweating – and by reflecting more solar energy out into space than darker vegetation such as forests – a phenomenon known as the albedo effect.

In 2007, Céline Bonfils and David Lobell of the Lawrence Livermore National Laboratory in California found that for much of the 20th century, temperatures in irrigated parts of California's Central Valley were http://www.newscientist.com/article/dn12482-cool-farms-mask-the-extent-of-global-warming.html">up to 1.6 °C cooler than modestly irrigated regions. This suggested that increased evaporation in the well-watered areas was responsible for the cooling.

…

[phantom power]

1. One wonders what happens when we can no longer irrigate.

[NickB79]

4. Look to the Dust Bowl for answers

Numerous high temperature records were set during that era as drought and overplowing turned green fields brown and creating a positive feedback loop.

[appal_jack]

5. we can do better than 'clean'-tillage, for sure

Organic minimum-till, undersowed cover-crops, alley-cropping between drought-tolerant trees, deep-mulching, and forest-farming/Permaculture are all options. None of these practices are easy at the large-scale, but all have potential to drastically reduce needs for irrigation waters.

-app

[JohnWxy]

2. uh-oh, some Direct cooling effects not attributed to biofuels!

[RaleighNCDUer]

3. And where's the water for all that irrigation coming from?

The glaciers are disappearing, reducing rivers; the aquifers are drying up after half a century of intensive irrigation.

As for cooling by reflection - ever spend any time in a desert? The soil is baked to a light tan, and there is nothing BUT reflection, and it is NOT cool. Forested regions, however, hold moisture and maintain coolness.

Are you sure this isn't an April Fools Day article?