As reported BBC new study suggest that the rate of global warming from doubling of atmospheric carbon dioxide (CO2) may be less than the most dire estimates of some previous studies. According to lead author Andreas Schmittner from Oregon State University, US, by looking at surface temperatures during the last Ice Age, 21,000 years ago, when humans were having no impact on global temperatures, he, and his colleagues, show that this period was not as cold as previous estimates suggest. This means that the effect of CO2 on climate is less than previously thought. The new models predict that given a doubling in CO2 levels from pre-industrial levels, the Earth‘s surface temperatures will rise by 1.7 to 2.6 degrees C.
Should also be noted that the new analysis also reduces the expected average surface temperatures to just over 2 degrees C, from 3.