Climatologists are breathing a collective sigh of relief. New data suggests that over the coming decade, the Earth will warm more slowly than previously thought. However, scientists stress that this is not a long-term reprieve – and temperatures are currently rising faster than they have been for the past 11, 000 years.
The Earth warmed very rapidly over the last half of the 20th century but the increase in temperature seemed to slow down in the last decade, most likely due to natural cycles in the climate system.
Researcher Alexander Otto at the University of Oxford and colleagues have used the latest data to determine how much fossil fuels have warmed the Earth over time. Then they examined the anticipated rise over the next few decades. What they determined is that global warming during the 21st century will be slower than previously understood.
However, Otto and his researchers stress this does not alleviate the problem and merely buys the Earth time to get CO2 emissions under control. The rise in temperatures on the planet long-term depends on how sensitive the climate is to CO2 accumulating in the atmosphere.
Even if greenhouse emissions stop, climate system delays mean that temperatures will continue to rise after CO2 concentrations double. The 2007 report of the Intergovernmental Panel on Climate Change (IPCC) estimated that temperatures will stabilize between 2 °C and 4.5 °C above pre-industrial temperatures. More and more climatologists think the climate is less sensitive to CO2 than the IPCC’s best estimate, so temperatures may rise less slowly than originally anticipated.