A broad look at possibilities for climate change suggests the planet could heat up much more significantly than other leading studies have predicted.
The global temperature could rise between 3.6 and 19.8 degrees Fahrenheit (2-11 Celsius), scientist report in the Jan. 27 issue of the journal Nature.
The report is the result of a collaborative Internet project called climateprediction.net. Like the popular SETI@home screensaver, software downloaded from climateprediction.net uses spare time on an individual's computer -- more than 90,000 people are participating so far -- to process one of more than 2,000 different climate models.
Whereas earlier studies generally plugged in the most likely assumptions, the computing power of the new project allowed a wider range of parameters for all the variables thought to affect climate change, including industrial carbon dioxide production and knowledge of how heat and chemicals move between the air and ocean.
Each of the many new models has different assumptions. Early in the project, those that best replicated history were selected for making prognostication for the future. The result is a larger range of results. Previous widely accepted climate models had predicted a temperature rise of 3.6 to 9 degrees Fahrenheit (2-5 Celsius).
Such extreme warming as possibly could occur given the newest predictions could take decades or centuries, the researchers say. A firm time frame can't be forecasted.
The results suggest the climate could be much more sensitive to increasing levels of greenhouse gases than thought, said project leader David Stainforth of the University of Oxford in the UK.
"The range of possibilities for future climate evolution needs to be taken into account when planning climate change mitigation and adaptation strategies," Stainforth and his colleagues write in the journal.
The project is ongoing.