Friday, July 17, 2009

BBC: Are the deserts getting greener?

It has been assumed that global warming would cause an expansion of the world’s deserts, but now some scientists are predicting a contrary scenario in which water and life slowly reclaim these arid places....
The Intergovernmental Panel on Climate Change warned recently that rising global temperatures could cut West African agricultural production by up to 50% by the year 2020. But satellite images from the last 15 years do seem to show a recovery of vegetation in the Southern Sahara
You know, what I'd really like to know is, on what basis was it "assumed" that global warming would cause an expansion of deserts, when we already know from the geological record that deserts tend to expand during cooler periods that have lower rainfall, not warmer periods that usually are wetter?
But this is old news in some ways.
I'm aware of another report a year or more ago that said that satellite imagery was clearly showing the Earth getting greener over the last 30 odd years.
Given all this, can you spot the elephant trying to hide in the corner?
Carbon dioxide is of course food for plants and they like higher concentrations of it in the atmosphere. I suspect our greening world is not unconnected to our carbon dioxide emissions.
Thanks to Andrew Bolt
And the tropical rain forests are expanding too, according to The New York Times.

Posted via email from Garth's posterous


Brentbo said...

The idea that increased co2 is actually beneficial, that idea, is starting to break out. How about this: Researchers have artificially increased CO2 levels in greenhouses up to 10 times the normal atmospheric levels, with no diminishing returns in plant growth.

Or this: ...for over 100 years, nurserymen have been adding carbon dioxide to their greenhouses to raise the yields of vegetables, flowers, and ornamental plants. And for decades, it has been well known among botanists, biochemists, agriculturalists, and foresters that a shortage of carbon dioxide is the most common limiting factor preventing photosynthesis from proceeding more efficiently.

Or even this: Elevating carbon dioxide levels can increase Cannabis growth speed a great deal, perhaps even double it. It seems that the plant evolved in primordial times when natural CO2 levels were many times what they are today. The plant uses CO2 for photosynthesis to create sugars it uses to build plant tissues. Elevating the CO2 level will increase the Cannabis plants ability to manufacture these sugars and plant growth rate is enhanced considerably.

Garth Godsman said...

Now, the cannabis example should really play with the hippies' heads!