Climate change and rising sea levels are currently on the right track to wipe out half of the world's sandy beaches by 2100, researchers warned on Monday.
Even if mankind greatly reduced the fossil fuel pollution that drives global warming, more than a third of the planet's sandy shores could disappear and paralyze coastal tourism in large and small countries by then, they reported in the journal Nature Climate Change ,
"Apart from tourism, sandy beaches are often the first line of defense against coastal storms and floods, and without them, the effects of extreme weather events are likely to be greater," said lead author Michalis Vousdoukas, a researcher at the European Commission's Joint Research Center. said AFP.
"We have to prepare."
Some countries, like the United States, are already planning large-scale defense systems, but in most countries, such massive engineering plans will not be viable, unaffordable, or both.
Australia could be hardest hit, according to the results, with nearly 15,000 kilometers of white coastline being washed away over the next 80 years, followed by Canada, Chile and the United States.
The 10 countries that will lose the sandy coast include Mexico, China, Russia, Argentina, India and Brazil.
Sandy beaches occupy more than a third of the global coast, often in densely populated areas.
But new buildings, rising sea levels, storm surges from hurricanes or typhoons and fewer sediments from dammed rivers are eroding these coasts and threatening livelihood and infrastructure.
To assess how quickly and by how much beaches could disappear, Vousdoukas and colleagues drew trend lines over three decades of 1984 satellite images.
From there, they predicted future erosion under two climate change scenarios.
The "worst case" RCP8.5 path assumes that carbon emissions will continue unabated or that the earth itself will increase atmospheric greenhouse gas concentrations – for example from permafrost – regardless of human actions.
"A milestone in progress"
In a less dire scenario called RCP4.5, humanity would limit global warming to about three degrees Celsius, which is still well above the "well below 2 ° C" limit required by the 2015 Paris Agreement.
Under RCP8.5, the world will lose 49.5 percent of its sandy beaches by 2100 – almost 132,000 kilometers of coastline.
Even by the middle of the century, the loss would be more than 40,000 kilometers.
The ever more likely RCP4.5 prospects would see 95,000 kilometers of sand cleared by 2100, most of them within the next 30 years.
The United Nations Science Advisory Group, the Intergovernmental Panel on Climate Change (IPCC), forecast in an important report last September that sea level would rise half a meter by 2100 under the more optimistic scenario and 84 cm below RCP8.5.
However, many climate researchers say that these estimates are too conservative and, in expert-reviewed work, have predicted that the ocean's watermark will increase twice as much.
Experts who were not involved in the new findings said they should raise the alarm.
"Linking global coastal degradation to combustion (fossil fuels) in the study is a milestone," said Jeffrey Kargel, senior scientist at the Planetary Research Institute in Tucson, Arizona.
In Asian delta regions, where hundreds of millions of people live, sediments from the Himalayan glacier melt that could build up sand deposits are trapped in downstream reservoirs. "Coastal erosion in the Indus and Ganges Delta regions of South Asia is expected to be extremely rapid," said Kargel.
The effects of coastal declines, which are still showing a thinning sand band, should also be considered, said Andrew Shepherd, director of the Center for Polar Observation and Modeling at the University of Leeds.
"Between a quarter and half of Britain's sandy beaches will retreat more than 100 meters over the next century, depending on how quickly polar ice sheets melt," he said.
"Unfortunately, ice losses from Antarctica and Greenland are pursuing the worst scenarios of global warming."
(This story was not edited by NDTV staff and is generated automatically from a syndicated feed.)