Climate change even worse

West Australian
Monday 16/2/2009 Page: 13

Dire warnings about the coming devastation wrought by global warming were not dire enough, according to a lead author of the Nobel Prize-winning Intergovernmental Panel on Climate Change report. It has been just over a year since the panel published its a report warning of rising sea levels, expanding deserts, more intense storms and the extinction of up to 30% of plant and animal species.

But recent climate studies suggest that report significantly underestimates the potential severity of global warming over the next 100 years, a senior member of the panel said. "We now have data showing that from 2000 to 2007, greenhouse gas emissions increased far more rapidly than we expected," said Chris Field, who was a coordinating lead author of the report.

This is "primarily because developing countries like China and India saw a huge upsurge in electric power generation, almost all of it based on coal," Professor Field said on Saturday ahead of a presentation to the American Association for the Advancement of Science.

Without decisive action to slow global warming, higher temperatures could ignite tropical forests and thaw the Arctic tundra, potentially releasing billions of tonnes of carbon dioxide that had been stored for thousands of years. That could raise temperatures even more and create "a vicious cycle that could spiral out of control by the end of the century". "We don't want to cross a critical threshold where this massive release of carbon starts to run on autopilot," Professor Field, a professor of biology and of environmental earth system science at Stanford University, said.

The amount of carbon that could be released was staggering. Since the beginning of the Industrial Revolution an estimated 350 billions tonnes of carbon dioxide (CO2) had been released through the burning of fossil fuels. The new estimate of the amount of carbon stored in the Arctic's permafrost soils was about 1000 billion tonnes. And the Arctic was warming faster than any other part of the globe.

Several recent climate models had estimated that the loss of tropical rainforests to big bushfires, deforestation and other causes could increase the concentration of CO2 in the atmosphere from 10 to 100 parts per million by the end of the century. It now was about 380 parts per million. "Tropical forests are essentially inflammable," Professor 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." Recent studies also showed that global warming was reducing the ocean's ability to store carbon by altering Southern Ocean wind patterns.

Professor Field is co-chair of the group assessing the impacts of climate change on social, economic and natural systems for the IPCC fifth assessment due in 2014. The fourth assessment in 2007 presented at a "very conservative range of climate outcomes" but the next report will "include futures with a lot more warming", Professor Field said.