The Guardian : “New evidence suggests the rate at which temperatures are rising in the northern hemisphere could be 0.25C per decade by 2020 – a level not seen for at least 1,000 years.”  

“The analysis, based on a combination of data from more than two dozen climate simulation models from around the world, looked at the rate of change in 40-year long time spans.”  

“Over the 900 years preceding the 20th century, 40-year warming trends rarely showed an average rate much higher than 0.1C per decade, the study found. But by 2020 the rate was expected to have risen to an average of 0.25C per decade, give or take 0.05C.”  

“The findings are published in the journal Nature Climate Change .”