A study published in Science journal, claims to have narrowed the range by which the world’s temperature can be expected to rise with a doubling of carbon dioxide concentrations from pre-industrial levels.
Earlier studies, including the Intergovernmental Panel on Climate Change’s (IPCC) 2007 report, have precicted a rise of between 2.0°C and 4.5°C, with a mean of about 3°C. The new study predicts that the Earth’s surface temperatures would rise by between 1.7°C and 2.6°C with a mean value of 2.3°C.
The new analysis uses palaeoclimate data going back to the latter stages of the most recent Ice Age, 21,000 years ago. The researchers believe that by incorporating this data into climate models, they can reduce the range of uncertainty in the model’s predictions.
Lead author Andreas Schmittner from Oregon State University, explained that by looking at how surface temperatures changed during a period when humans were having no impact on global temperatures, his team showed that it had not been as cold as previous estimates had suggested.
The authors stress that the results do not mean that the threat from human-induced climate change should be treated any less seriously but they do indicate that it may take a longer than previously thought to induce large-scale warming of the planet, leading to widespread catastrophic consequences.