The authors say that rising sea levels could cost the global economy $ 14.2 trillion in lost or damaged assets by the end of the century, as large areas of land, home to millions of people, are flooded.
“This is in a ‘business as usual’ CO2 emissions scenario,” said Ebru Kirezci of the University of Melbourne, who led the study. “Business as usual” assumes an increase in average global temperatures at the high end of predictions, if global emissions are allowed to continue on their current course.
As temperatures and sea level rise, the study estimates that up to 287 million people could be exposed to episodic coastal flooding by 2100, up from a peak of 171 million today. More than a million square kilometers of coastline could also be compromised, an area almost twice the size of France.
Areas at highest risk for extensive flooding include the northeast coast of the United States, northwest Europe, and large parts of Asia, including countries around the Bay of Bengal, Indonesia, China, and northern Australia, according to the authors.
Some of the most Vulnerable areas are low-income, highly populated regions that are already facing devastating annual floods.
The authors say their figures do not take into account coastal defenses or projected increases in the world economy or population by 2100. However, they say putting a dollar figure at worst could spur policy change sooner. it’s too late
“If you want politicians to realize it, you have to put it in terms that resonate with them. The terms that resonate with them are economic impacts,” said Ian Young, professor of engineering at Kernot University of Melbourne and co-author. from The Study.
All about extremes
Rather than focusing on the mean or average sea level rise, the study looks at sea levels during extreme storms in the past 30 years to model the maximum area that could be at risk of flooding.
They mapped all flood events “one in 100 years,” particularly storm surge and destructive flooding resulting from intense storms and cyclones, off the coast of the world. Combining these data with projections of sea level rises under different greenhouse gas emission scenarios, the authors modeled the maximum increases in sea levels.
“We are looking at the extremes,” Young said. “Being able to model the tide, the storm surge, the formation of waves, the rise in sea level, the extremes that this generates and doing it on a global scale, that is the only thing about this project.”
If nothing is done to reduce carbon emissions, By 2100, vulnerable areas that are at risk of a “one in 100 years” flood event will experience them once every decade, the authors found.
“We are already seeing increased frequency of storm surges and extreme sea levels,” said Kirezci. “The risks are increasing and climate change exacerbates these impacts.”
To reach the economic cost of more major floods, the researchers combined their model with topographic data to identify areas at risk of coastal flooding, as well as map that to population and GDP data in those affected areas.
“Our main objective with the study was to inform decision makers and policy makers around the world so that we can identify the hot spots, the most vulnerable areas, on the global coasts,” said Kirezci.
What that means for vulnerable countries and populations.
Severe flooding already costs billions of dollars each year in damage, as homes, buildings and vital infrastructure such as highways, pipelines and pylons and farmland are destroyed.
Kirezci’s study suggests that those social and economic costs will only worsen if calls to build more flood defenses are ignored.
“As with many environmental problems, it is the poor who are most affected,” Young said. “The real humanitarian challenge will be what you do. Can you really afford to build coastal defenses? Do you have to relocate populations? How would you do that?”
Scientists say that even if we reduce greenhouse gas emissions now, there is some sea level rise inevitable.
“Regardless of what we do with the change in our climate, those sea level rises are going to occur,” Young said.
The researchers say that in addition to reducing emissions, countries should invest in adaptation measures to protect themselves against future floods. These include building natural defenses such as mangroves and seagrasses that absorb waves and tidal waves along the coasts, as well as feeding the beach, where the sands move to reinforce the beaches and dunes.
As a last resort, the researchers say, entire populations may have to be pushed away from the coast, a costly and highly disruptive move that could cause major humanitarian problems.
Kirezci said that people should be aware of the impact of the climate crisis on sea level. “We need to raise awareness about the coastal communities, which reside in the lowlands,” he said.
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