Has a Key Global Warming Tipping Point Already Been Passed?

An explanation by climate scientists of why carbon dioxide levels in the atmosphere have recently been spiking suggests that global warming is now reducing the ability of the environment to absorb carbon dioxide from human sources. An article in The Sydney Morning Herald says that scientists have been fearing that increasing temperatures could reduce carbon absorption by the environment. If this tipping point has in fact been reached, then even the recent report by the Intergovernmental Panel on Climate Change which said that reduction of carbon emissions must begin globally no later than 2015 to avoid catastrophic climate change (see previous post) may need to be revised to an even more pessimistic conclusion. The research team, which published their findings in Geophysical Research Letters, studied the spike in atmospheric carbon dioxide levels during 2002 to 2003. The scientists found that the only explanation for the spike was that because of unusual conditions of heat and dryness plants took up less carbon dioxide that they normally do. So, is unstoppable global warming already here? Perhaps that might be the next inconvenient truth.