The Amazon is finally coming out of a record drought, which began last April. According to the latest post from Wunder Blog : Weather Underground, less than 75% of the expected annual rain fell in the southern Amazon, and the largest northern tributary of the Amazon, the Rio Negro, fell to 13 feet below its normal level.
Perhaps the most worrisome aspect of the drought, unlike those of the 20th Century, was that this was not an El Niño year. Neither was the record-setting drought of 2005, which was driven by high sea surface temperatures in the Atlantic. Those surface temperatures recurred this year, and analysis will probably show that this year’s drought was driven by them.
The takeaway: the Amazon may be shifting to a new pattern, in which droughts are driven not by El Nino, which recurs every five years or so, but by sea surface temperatures, which are on the rise.
This is especially sobering, given that growth in the Amazon rainforest removes about 2 billion tons of CO2 per year from the atmosphere. The 2005 drought put this into reverse, and the Amazon added 3 billion tons of CO2, “roughly equivalent to 16 – 22% of the total CO2 emissions … from burning fossil fuels.”
This points to a very large positive feedback loop by which an increase in global temperature leads to drought which leads to further increase in temperature which etc.
For details and graphics, see Wunder Blog : Weather Underground