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Sustainability August 10, 2016
Remember those days you spent on a grassy field, staring wide-eyed as voluminous clouds drifted across a blue sky? Maybe you were even the type of woman who enjoyed differentiating between the cumulonimbus and cirrus clouds in the sky. And every chance you got, you’d point out a turtle in the clouds while your brother argued that it looked more like a pig. Well, according to recent findings, cloud formations such as these may be declining as a result of global warming.
Joel Norris of the University of California San Diego’s Scripps Institution of Oceanography conducted the study, which was published in the international journal, Nature. The prime method of observation for the study was using weather satellites to identify trends in cloud patterns from 1983 to 2009. While researchers soon realized that these satellites were created for studying weather, not clouds, Norris and his colleagues were able to sift through many of the obstacles in the satellite data to view solely the cloud patterns.
Their main findings were that cloud concentrations have gradually decreased in the subtropics, thus leading to more dry periods. Additionally, the top levels of clouds are climbing higher, which leads to less thermal radiation emitted into space.
If subtropical regions get drier, temperatures will rise and droughts will increase. Cloud patterns are extremely difficult to track, as there aren’t instruments available that can accurately follow them. Collecting data on clouds is comparable to that of the weather—extremely variable and uncertain, often because of faulty sensors.
There is also more radiation in the subtropics, so it’s better to have clouds there to reflect it into space. Not only that but thicker, low clouds aid the cooling process by absorbing and reflecting radiation into space while thinner, high clouds tend to trap radiation so that it remains on the Earth’s surface. Trapped radiation contributes to the warming.
There is some speculation from other researchers about whether the shift in cloud patterns is because of recent volcanic eruptions and not just climate change. Kate Marvel, who is a climate researcher with NASA’s Goddard Institute for Space Studies, told The Guardian that the observed cloud shifts could result from the two major volcanic eruptions which occurred while the study was being conducted.
Norris says that he plans to address this in future research. He did account, however, for natural variability by comparing the study results to climate models and no significant similarities were found.
The challenges researchers faced while conducting this study indicates a lack of proper technology that needs to be improved upon. It is also more or less the first of its kind; it is only the beginning of a branch of research linking cloud changes to global warming.
