Failure to reduce carbon dioxide emission can cause global temperatures to rise by a minimum of 4°C by 2100 and double by 2200, according to a University of New South Wales study. Researchers said that global climate is more affected by carbon dioxide emission than previously believed.

The study also said that as the planet gets warmer; fewer clouds are formed, giving way to rising temperatures.

"Our research has shown climate models indicating a low temperature response to a doubling of carbon dioxide from pre-industrial times are not reproducing the correct processes that lead to cloud formation," Professor Steven Sherwood said in a press release.

"When the processes are correct in the climate models, the level of climate sensitivity is far higher. Previously, estimates of the sensitivity of global temperature to a doubling of carbon dioxide ranged from 1.5°C to 5°C."

The researchers derived the findings by studying water vapor in cloud formations.

They said that when water evaporates, they either move 15 kilometers (about nine miles) up forming rainclouds or only rise a few kilometers without forming clouds.

The updraughts that travel only a few kilometres 'pull vapor away from' the clouds at a higher level (rainclouds). This results in reducing the overall cloud cover.

Researchers now feel that existing climate models might be overestimating the number of clouds protecting the atmosphere. The existing models don't consider the vapor being pulled down by the lower level clouds. As a result, the global temperatures in these models are less sensitive to carbon dioxide emission.

This new model that includes the process found the formation of fewer clouds. This process lets a larger amount of sunlight into the atmosphere which raises 'sensitivity of our climate to carbon dioxide or any other perturbation.'

"Climate sceptics like to criticize climate models for getting things wrong, and we are the first to admit they are not perfect, but what we are finding is that the mistakes are being made by those models which predict less warming, not those that predict more," Sherwood said.

"Rises in global average temperatures of this magnitude will have profound impacts on the world and the economies of many countries if we don't urgently start to curb our emissions."

The findings have been published in the journal Nature.

Topics Carbon dioxide, University of New South Wales, Planet