These stunning satellite images show the effects of climate change on Earth – Evening edition Ouest-France – 18/08/2022


By Nicolas HASSON-FAURÉ For half a century, the satellites of the American Landsat program have been photographing the Earth’s surface non-stop. His images show a changing planet, which is experiencing drought or the retreat of glaciers under the effect of climate change. Zoom in on these phenomena, seen from space. The huge, dark blob has lost much of its surface. The waters of Lake Mead, the largest reservoir of water in the United States, are slowly being eaten away by barren, sandy lands. The man-made lake is inexorably drying up, as shown by two images taken in 2000 and then in 2021 by the satellites of the American Landsat program, which began fifty years ago. The first of these eight spacecraft into orbit was launched on July 23, 1972. For half a century, they have been photographing the Earth’s surface non-stop, leading them to take “an unbiased look at climate change,” states the United States Geological Survey. Survey (USGS), which leads this program with NASA, the US space agency. Drought, retreating glaciers… Satellite observations show a changing planet, affected by climate change. Here are three illustrations, seen from space. 1. Melting glaciers Satellite view of the Tibetan Plateau, taken on October 12, 1987. (Photo: Landsat Image Gallery / Public Domain) This same Tibetan Plateau as seen from space, 9 of October 2021. (Photo: Landsat Image Gallery / Public) Located in the mountains and straddling several Asian countries, the Tibetan Plateau is nicknamed “the third pole” because it concentrates the largest reserves of fresh water outside the North Pole and the South Pole, according to the USGS. The region’s blue gold is found, in particular, in the “tens of thousands of glaciers” that dot this vast territory. Problem: They are retreating inexorably under the effect of rising temperatures, as evidenced by images captured by US satellites in 1987 and then in 2021. In 34 years, the ice sheet has declined sharply, a phenomenon also visible in the video of this animation produced by NASA: The Tibetan Plateau, home to tens of thousands of glaciers, is very sensitive to climate change. Water from melting glaciers has created hundreds of new lakes and enlarged existing ones, like the main pair shown here. Learn more in our Images of Change: — NASA Climate (@NASAClimate) February 22, 2022 The glaciers on the Tibetan Plateau aren’t the only ones retreat globally. And other satellite photos prove it, like these images of the Columbia Glacier in Alaska, taken in 1986 and then in 2014. One note: these are not the actual colors, the photos have been recolored to highlight the phenomenon Columbia Glacier in 1986. (Photo: Landsat Image Gallery / Public Domain) The glacier in 2014. (Photo: Landsat Image Gallery / Public Domain) 2. Drought The drying up of Lake Mead between August 2000 and August 2021. (Photo: Landsat Image Gallery/Public Domain) Other satellite images show what Lake Mead looks like in the western United States from space. The photos highlight the inexorable desiccation of the Great Reservoir Plan of the United States, located in Nevada: at the end of July, the water level was at its lowest level since 1937 and the filling of the artificial lake, indicated then the American newspaper The News from New York. It was then filled to 27% capacity! See also: United States. ‘It’s beyond drought’: Lakes Mead and Powell are turning into ‘dead basins’ This trend is explained by the ‘mega-drought’ that has affected the North American Southwest since 22 years: It is the longest known since 800 AD, more than 1,200 years ago, according to a study published in the journal Nature Climate Change last February. Lake Mead’s name has been in the international media in recent weeks: here, receding water has revealed human bones, which could belong to people killed by the underworld decades ago, whose bodies had been dumped in the lake. so that they never meet. 3. Devastating storms Photo of part of the Texas coast before the passage of Hurricane Harvey on August 25, 2017. (Photo: USGS EROS / Public Domain) The same area after the hurricane passed through on September 5, 2017. (Photo: USGS EROS / Public Domain) Satellite camera lenses also captured images of devastation, such as the stunning flooding caused by Hurricane Harvey in Texas in the southern United States in 2017. The storm killed at least 68 people in that state alone (it also affected other parts of the country) according to the National Oceanic and Atmospheric Administration (NOAA). As for material damage, it was estimated at 125 billion dollars, that is, more than 122 billion euros. However, “it is difficult, if not impossible, to assess the impact of global warming caused by human activities on a given storm,” states the USGS. But this climate change has increased the amount and intensity of the heavy rains caused by the hurricane, according to several scientific studies published in 2017 and cited by the Science Daily website. Climate change has an effect on the intensity of these weather phenomena. “The fuel for cyclones is the temperatures observed on the surface of the oceans. The higher these temperatures are, the more energy there is in the hurricane system, explained Fabrice Chauvin, a climatologist at the National Center for Meteorological Research in 2021 in western France. Not all cyclones will get stronger, it is the proportion of large cyclones that will get bigger. »

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