By Editorial staff with AFP
MEven if humanity manages to limit warming to 1.5 ° C compared to the pre-industrial era, sea levels will rise for centuries, inundating cities currently inhabited by half a billion people, warned people. scientists.
If the planet heats up by half a degree more, 200 million additional city dwellers will be regularly affected by floods and made more vulnerable during storms, they wrote in the review. Environmental Research Letters.
Asia, which has nine of the ten highest-risk mega-cities, will be the hardest hit.
Most current estimates of sea level rise and the threats it poses to coastal towns run to the turn of the century and range from half a meter to less than a meter.
But the phenomenon will continue beyond 2100 under the effect of warming water and melting ice, regardless of the speed of reduction in greenhouse gas emissions.
“About 5% of the world’s population currently lives on land below the level that will be reached at high tide as a result of carbon dioxide already accumulated in the atmosphere by human activity,” said the lead author. from the article Ben Strauss, President and Chief Research Officer of the Independent Organization of Journalists and Scientists Climate Central.
The current concentration of CO2 is 50% higher than that of 1800 and the average temperature on the Earth’s surface has increased by 1.1ºC.
That’s enough to raise sea levels by almost two meters, whether it takes two centuries or ten centuries, says Strauss.
The 1.5 degree limit enshrined in the Paris Agreement and which countries around the world will try to maintain at the COP26 summit in Glasgow next month translates to a rise in water levels of almost three meters in the long term.
The Climate Central team also attempted to concretely illustrate the consequences linked to these different scenarios of rising water levels in providing images of more or less flooded historical places (New window), depending on the severity of global warming.
Climate Central ran simulations for 180 locations to show what the world might look like if the temperature rose 1.5 degrees, 3 degrees, or even 4 degrees. Museums, cathedrals, temples and famous public places around the world would be particularly at risk of being partially or completely inundated. It should be noted that these simulations are carried out for cities located at sea level, therefore at low altitude and in the case where man does nothing to counter global warming.
Some examples of simulations
The simulation was carried out in particular for the city of Antwerp. The inevitable scenario of a warming to 1.1 ºC is shown on the left. On the right, it reaches more like 3 ºC.
The map of Belgium “under water”