Researchers find clouds contain more liquid – as opposed to ice – than was previously believed, threatening greater increase in temperatures
Thursday 7 April 2016
Climate change projections have vastly underestimated the role that clouds play, meaning future warming could be far worse than is currently projected, according to new research.
Researchers said that a doubling of carbon dioxide in the Earth’s atmosphere compared with pre-industrial times could result in a global temperature increase of up to 5.3C – far warmer than the 4.6C older models predict.
The analysis of satellite data, led by Yale University, found that clouds have much more liquid in them, rather than ice, than has been assumed until now. Clouds with ice crystals reflect more solar light than those with liquid in them, stopping it reaching and heating the Earth’s surface.
The underestimation of the current level of liquid droplets in clouds means that models showing future warming are misguided, says the paper, published in Science. It also found that fewer clouds will change to a heat-reflecting state in the future – due to CO2 increases – than previously thought, meaning that warming estimates will have to be raised.
Such higher levels of warming would make it much more difficult for countries to keep the global temperature rise to below 2C, as they agreed to do at the landmark Paris climate summit last year, to avoid dangerous extreme weather and negative effects on food security. The world has already warmed by 1C since the advent of heavy industry, driven by CO2 concentrations soaring by more than 40%.
A lack of data and continuing uncertainty over the role of clouds is to blame for the confusion about warming estimates, said Ivy Tan, a graduate student at Yale who worked on the research with academics from Yale and the Lawrence Livermore National Laboratory.