The latest on global warming from a Stanford researcher

Chris Field, a member of the Intergovernmental Panel on Climate Change, believes the latest climate predictions may be understimating the problem. Here are three reasons why:

1. Coal

   "We now have data showing that from 2000 to 2007, greenhouse gas emissions increased far more rapidly than we expected, primarily because developing countries, like China and India, saw a huge upsurge in electric power generation, almost all of it based on coal," Field said.
   
   This trend is likely to continue, he added, if more developing countries turn to coal and other carbon-intensive fuels to meet their energy needs. "If we're going to continue re-carbonizing the energy system, we're going to have big CO2 emissions in the future," he said. "As a result, the impacts of climate change will probably be more serious and diverse than those described in the fourth assessment."

2. Tropical forests

   "Tropical forests are essentially non-flammable," Field said. "You couldn't get a fire to burn there if you tried. But if they dry out just a little bit, the result can be very large and destructive wildfires."
   
   According to several recent climate models, loss of tropical forests to wildfires, deforestation and other causes could increase atmospheric carbon dioxide concentrations from 10 to 100 parts per million by the end of the century. This would be a significant increase, given that the total concentration of carbon dioxide in the atmosphere is currently about 380 parts per million, the highest in 650,000 years.
   
   "It is increasingly clear that as you produce a warmer world, lots of forested areas that had been acting as carbon sinks could be converted to carbon sources," Field said.

3. Arctic tundra

   "The new estimate of the total amount of carbon that's frozen in permafrost soils is on the order of 1,000 billion tons," he said. "By comparison, the total amount of CO2 that's been released in fossil fuel combustion since the beginning of the Industrial Revolution is around 350 billion tons. So the amount of carbon that's stored in these frozen soils is truly vast."
   
   Much of the carbon is locked up in frozen plants that were buried under very cold conditions and have remained in deep freeze for 25,000 to 50,000 years, he added. "We know that the Arctic is warming faster than anyplace else," he said. "And there is clear evidence that these frozen plants are very susceptible to decomposition when the tundra thaws. So melting of permafrost is poised to be an even stronger foot on the accelerator pedal of atmospheric CO2, with every increment of warming causing an increment of permafrost-melting that shoots an increment of CO2 into the atmosphere, which in turn increases warming.