The elevation of sea level will become unmanageable at only 1.5 ° C of global heating and will lead to an “interior catastrophic migration”, warned scientists behind a new study. This scenario can take place even if the average heating level in the last decade of 1.2C continues in the future.
The loss of ice in giant glacial calculations of Greenland and Antarctica has been quadrupled since the 1990s due to the climate crisis and is now the main engine of sea level elevation.
The international objective to maintain an increase in global temperature below 1.5 ° C is already almost out of reach. But the new analysis revealed that even if fossil fuels emissions were quickly reduced to reach it, sea level would increase by 1 cm per year at the end of the century, faster than the speed at which nations could build coastal defenses.
The world is on the right track for 2.5C-2.9 ° C of global heating, which would almost certainly be beyond the tips for the collapse of the glacial caps of the Antarctica of Greenland and the West. The fusion of these glacial caps would lead to a “truly terrible” 12 meters elevation of sea level.
Today, around 230 million people live less than 1 meter above the current sea level and 1 billion live less than 10 meters above sea level. Even only 20 cm of sea level elevation by 2050 would cause world flood damages of at least 1 TN per year for the 136 largest coastal cities in the world and enormous impacts on people’s lives and livelihoods.
However, scientists have stressed that each fraction of a global degree of heating avoided by climate action is always important, because it slows down the elevation of sea level and gives more time to prepare, reducing human suffering.
The elevation of sea level is the largest long -term impact of the climate crisis, and research in recent years has shown that it occurs much faster than that previously estimated. The 1.5 C limit has been considered a way to avoid the worst consequences of global heating, but the new research shows that this is not the case for elevation of sea level.
The researchers said that the “safety limit” temperature for glacial caps was difficult to estimate but was probably 1C or lower. An increase in sea level at least 1-2 meters was now inevitable, scientists said. In the United Kingdom, only 1 meter of sea level elevation would see large parts of the fens and humberside from sea level.
“What we mean for security security is one that allows a certain level of adaptation, rather than catastrophic interior migration and forced migration, and the safety limit is approximately 1 cm per year of sea level elevation,” said Professor Jonathan Bamber of the University of Bristol in the United Kingdom. “If you get there, then it becomes extremely difficult for any type of adaptation, and you will see a migration of massive lands on scales that we have never seen in modern civilization.” Developing countries like Bangladesh would be much worse than the rich with experience of restraint of waves, like the Netherlands, he said.
Professor Chris Stokes of the University of Durham, principal author of the study, said: “We are starting to see some of the worst scenarios take place almost before us. At the current warming of 1.2C, the elevation of sea level accelerates at rates which, if they continue, would become almost unmanageable before the end of this century, (which is) in the life of our young people. “
The average global temperature reached 1.5 ° C for the first time in 2024. But the international objective is measured as the average of more than 20 years, it is therefore not yet considered to have been broken.
After promoting the newsletter
The new study, published in the journal Communications Earth and Environment, combined data from hot period studies up to 3m 3m ago; Observations of the fusion of ice and the elevation of sea level in recent decades; and climate models. He concluded: “The continuous loss of mass of glacial caps is an existential threat to world coastal populations.”
Professor Andrea Dutton of the University of Wisconsin -Madison, who was part of the study team, said: “The evidence recovered in previous hot periods suggest that several meters of sea level elevation – or more – can be expected when the global average temperature reaches 1.5 ° C or more.”
At the end of the last glacial period, about 15,000 years ago, sea level increased the rate today, driven by self-reproductive feedback which may have been triggered by a low temperature increase. The last time co2 The levels in the atmosphere were as high as today, there are approximately 3m, the elevation of sea level was 10 to 20 meters more.
Even if humanity can bring the planet back to its pre -industrial temperature by eliminating the CO2 From the atmosphere, it will always take hundreds of years to thousands of years so that the glacial caps are recovered, the researchers said. This means that the lands lost against elevation of sea level will remain lost for a long time, perhaps until the earth enters the next glacial period.
The Belize moved its capital in terms of land in 1970 after a devastating hurricane, but its largest city is still on the coast and will be flooded with only 1 meter increase in sea level, Carlos Fuller, the long-standing climate negotiator of Belize, said: “The results such as these can only restore to lower temperatures and to protect our limits possible.
