Fluffy, low-hanging clouds generally have a cooling influence. They are big and bright, blocking and bouncing back incoming sunlight. | AFP-JIJI AFP-JIJI Paris – People have always studied the skies to predict the weather, but recently scientists have noticed that clouds are changing on a global scale — posing one of the greatest challenges to understanding our warming world. Some clouds are rising higher into the atmosphere, where they trap more heat. Others are reflecting less sunlight, or shrinking and allowing more solar energy to reach Earth’s surface. Scientists know this is affecting the climate, because the vital role that clouds play in warming and cooling the planet is well understood. Recent research has shown that clouds — or rather, a lack of them — helped drive a stunning surge in record-breaking global heat over the last two years. What is less certain is how clouds might evolve as the world warms. Will they have a dampening effect on global warming, or amplify it? And if so, by how much? “That’s why clouds are the greatest challenge. Figuring them out is — and has been — the big roadblock,” said Bjorn Stevens from the Max Planck Institute for Meteorology in Germany, who has written extensively on the subject. Cloud behavior is notoriously complex to predict and remains a great unknown for scientists trying to accurately forecast future levels of climate change. Changes in clouds could mean that, even with the same amount of heat-trapping greenhouse gas emissions, “we could get much more warming or much less warming”, said Robin Hogan, principal scientist at the European Centre for Medium-Range Weather Forecasts. “That’s a big scientific uncertainty,” he said. With satellites and supercomputers, scientists are improving cloud modelling and slowly filling in the missing pieces of the puzzle. Part of the […]
Click here to view original web page at www.japantimes.co.jp