Current scientific models 'underestimate climate change'

The increase in the Earth's temperature as a result of climate change is likely to be higher than previously expected. A new study has found that carbon dioxide emissions are having more of an impact on global temperatures than anticipated, meaning the Earth could experience a four degrees Celsius increase by 2100.

New research into cloud systems, published in the journal 'Nature', outlines how the sensitivity of global climate is affected by cloud formation. Led by Professor Steven Sherwood from the University of New South Wales, Australia, with researchers from Universite Pierre et Marie Curie, France, the research found that current climate models do not factor in water vapour that is released into the atmosphere.

According to the study, current models only factor in water vapour reaching heights of 15 kilometres, at which point it forms clouds. This means water vapour caught on updraughts below this height, which then pull vapour that forms clouds away, is not accounted for.

Understanding cloud movements is vital to understanding the true extent that the Earth can be affected by climate change, as clouds reflect sunlight and therefore lessen the increase in global temperatures.

Researchers therefore concluded that models currently in use are incorrect. The study found that fewer clouds are being formed as temperatures increase across the globe because water vapour is rising to different heights in the atmosphere. 

The creation of fewer clouds means temperatures are increasing more rapidly as less sunlight is bounced away from the Earth. This in turn means the atmosphere is more sensitive to greenhouse gases.

Researchers conclude that temperatures will increase by "at least" four degrees Celsius by 2100 if predictions concerning the doubling of current atmospheric carbon dioxide levels are correct. By 2200, this could result in a temperature increase of over eight degrees Celsius.

This temperature forecast doubles the current two degrees Celsius limit that has been agreed by countries throughout the globe in a bid to reduce the impact of climate change. 

Professor Sherwood told the Guardian: “Climate sceptics like to criticise 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.

“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."