Farmers and Global Warming

I also read the print version of the lead article for the March 2005 edition is (you will need to either buy the magazine or subscribe online to read the whole article):

Scientific American: How Did Humans First Alter Global Climate? [ CLIMATOLOGY ]
A bold new hypothesis suggests that our ancestors' farming practices kicked off global warming thousands of years before we started burning coal and driving cars

Some banal comments are:

• Trees bad, farming good (unless you like lots of snow and ice)
• Fatulence good for the same reason
• Chinese rice farmers good for the same reason

I find it hard to believe that there were enough people in the whole world 8,000 years ago to clear enough forests in order to farm, that the downward trend in the proportion of carbon dioxide in the air was stopped and reversed. Our ancestors must have been beavers to clear that much timber - puts the Tasmanian Timber Industry to shame (slackers!).

On the other hand, irrigated rice production in Southern China stopped the downward trend in the proportion of Methane in the air at about 5,000 years ago. All that rotting vegetation lying in water produces Methane. Again, I am amazed that there were enough people alive then to have such an effect.

The author contends that, so far, farming has contributed 0.8 degree C to global warminng while industrialisation has contributed 0.6 degree C (but is gaining fast).

The problem of global warming is not that it is occurring but how can we manage it for the survival of the human species, and other species as well?

There is a sidebar to this article that purports to show that pandemics influence the proportion of Carbon Dioxide in the air by killing enough people so that forests have time to grow back and stored away Carbon Dioxide. The accompanying graph belies his whole thesis. Maybe I am just a dunderhead.