10 January 2011
CO2 "inertia" makes significant climatic disruption inevitable
by Kate Melville
The first full climate simulation to make predictions out to the year 3000 indicates that even if zero CO2 emissions were achieved immediately, the inertia of past carbon dioxide emissions would continue affecting the planet for the next 1000 years.
Appearing in the journal Nature Geoscience, the new work is based on best-case, "zero-emissions" scenarios constructed by a team of researchers from the Canadian Centre for Climate Modeling and Analysis and the University of Calgary.
"We created 'what if' scenarios," says Dr. Shawn Marshall, Canada Research Chair in Climate Change and University of Calgary geography professor. "What if we completely stopped using fossil fuels and put no more CO2 in the atmosphere? How long would it then take to reverse current climate change trends and will things first become worse?"
Marshall said that the Northern Hemisphere fares better than the south in the computer simulations, with patterns of climate change reversing within the 1000-year timeframe in places like Canada. But at the same time, parts of North Africa experience desertification as land dries out by up to 30 percent, and ocean warming of up to 5& #176;C off of Antarctica is likely to trigger the total collapse of the West Antarctic ice sheet.
The researchers hypothesize that the variability between the North and South is due to the slow movement of ocean water from the North Atlantic into the South Atlantic. "The global ocean and parts of the Southern Hemisphere have much more inertia, such that change occurs more slowly," explains Marshall. "The inertia in intermediate and deep ocean currents driving into the Southern Atlantic means those oceans are only now beginning to warm as a result of CO2 emissions from the last century. The simulation showed that warming will continue rather than stop or reverse on the 1000-year time scale."
Marshall and his co-researchers will next begin to investigate more deeply the impact of atmosphere temperature on ocean temperature to help determine the rate at which West Antarctica could destabilize and how long it may take to fully collapse into the water.
Source: University of Calgary