Farmers who cleared huge swathes of forests to grow crops thousands of years ago could have increased carbon dioxide levels enough to change the climate, researchers claimed todayMy theory differs to theirs in that it is probably the herds of flying pigs farting that has caused it.
There was far less arable land in those days as the population was far smaller. Kent, for instance, was mainly forest until the Napoleonic wars. Why didn't the carbon dioxide levels really not leap up in the 18th and 19th century? Slash and burn was far more prevalent then.
They never give up do they?