Sea level rise will become unmanageable at just 1.5C of global heating and lead to “catastrophic inland migration”, the scientists behind a new study have warned.
The melting of those ice sheets would lead to a “really dire” 12 metres of sea level rise.
Today, about 230 million people live within 1 metre above current sea level, and 1 billion live within 10 metres above sea level.
Sea level rise of at least 1-2 metres was now inevitable, the scientists said.
In the UK, just 1 metre of sea level rise would see large parts of the Fens and Humberside below sea level.
At just 1 point 5C of global warming, sea level rise will become uncontrollable and cause “catastrophic inland migration,” according to the scientists leading a new study. Even if the average warming of the past ten years—1 point 2C—continues into the future, this scenario could still occur.
The primary cause of sea level rise is now the quadrupling of ice loss from the massive Greenland and Antarctic ice sheets since the 1990s as a result of the climate crisis.
The international goal of limiting the rise in global temperatures to less than 1 degree Celsius is already nearly unattainable. However, the new analysis discovered that sea levels would rise by 1 cm annually by the end of the century, surpassing the rate at which countries could construct coastal defenses, even if fossil fuel emissions were drastically reduced to meet it.
With global warming expected to reach 2.5C to 2.9C, the Greenland and west Antarctic ice sheets are most likely to have melted. The sea level would rise by a “very dire” 12 meters as a result of those ice sheets melting.
Approximately 230 million people currently reside within 1 meter of the sea level, and 1 billion within 10 meters. Sea level rise of even 20 cm by 2050 would have a significant impact on people’s lives and means of subsistence and cause flood damages to the world’s 136 largest coastal cities of at least $1 trillion annually.
Nevertheless, the scientists emphasized that every degree of global warming that climate action prevents still counts because it slows sea level rise, gives people more time to prepare, and lessens human suffering.
The largest long-term effect of the climate crisis is sea level rise, which is happening much more quickly than previously thought, according to recent research. According to the latest research, the 1point 5C limit was thought to be a means of preventing the worst effects of global warming, but this is not the case for sea level rise.
The “safe limit” temperature for ice sheets, according to the researchers, is probably 1C or less, though it is difficult to determine. According to the scientists, sea level rise of at least one to two meters was now unavoidable. The Fens and Humberside would be below sea level in the UK if sea levels rose by just 1 m.
“A safe limit is one that permits a certain amount of adaptation, as opposed to catastrophic inland migration and forced migration,” stated Professor Jonathan Bamber of the University of Bristol in the United Kingdom. The safe limit is approximately 1 centimeter of sea level rise annually. “Any adaptation will become very difficult if you reach that point, and you’ll witness unprecedented levels of land migration in contemporary civilization. “Developing nations like Bangladesh would suffer far more than wealthy nations like the Netherlands that have experience containing the waves,” he said.
The study’s lead author, Professor Chris Stokes of Durham University, stated: “We’re beginning to see some of the worst-case scenarios play out almost in front of us.”. Sea level rise is accelerating at a rate that, if it continues, would become nearly uncontrollable before the end of this century, [that is,] within the lifetime of our young people, given the current warming of 1 point 2C. “”.
In 2024, the average global temperature reached 1 degree 5 Celsius for the first time. However, since the global goal is based on the average over a 20-year period, it has not yet been surpassed.
Data from studies of warm periods up to three million years ago, observations of ice melting and sea level rise in recent decades, and climate models were all combined in the new study, which was published in the journal Communications Earth and Environment. “The world’s coastal populations face an existential threat due to the ongoing mass loss from ice sheets,” the report concluded. “.”.
“Evidence recovered from past warm periods suggests that several meters of sea level rise – or more – can be expected when global mean temperature reaches 1.5C or higher,” the study’s lead author, Professor Andrea Dutton of the University of Wisconsin-Madison, stated. “”.
Due to self-reinforcing feedbacks that might have been set off by a mere rise in temperature, the sea level was rising ten times faster at the end of the last ice age, some 15,000 years ago. Sea levels rose 10–20 meters higher when CO2 levels in the atmosphere were as high as they are now, which was roughly 3 million years ago.
The researchers noted that it will take hundreds to thousands of years for the ice sheets to recover, even if humans are able to remove CO2 from the atmosphere and return the planet to its preindustrial temperature. This implies that land lost to sea level rise will be gone for a very long time—possibly until the next ice age begins.
Carlos Fuller, Belize’s longtime climate negotiator, stated: “Findings like these only sharpen the need to remain within the 1.5C Paris agreement limit, or as close as possible, so we can return to lower temperatures and protect our coastal cities.” Belize moved its capital inland in 1970 following a devastating hurricane, but its largest city is still on the coast and will be inundated with only 1 meter of sea level rise. “.”.
