A new study has warned that sea level rise will become unmanageable at just 1.5°C of global heating, leading to “catastrophic inland migration”. Even if the average level of heating over the last decade of 1.2°C continues into the future, scientists predict a similar outcome.
The loss of ice from giant Greenland and Antarctic ice sheets has quadrupled since the 1990s due to climate change. This is now the principal driver of sea level rise. The international target to keep global temperature rise below 1.5°C is already almost out of reach.
However, even if fossil fuel emissions are rapidly slashed to meet this target, sea levels would still be rising by 1 centimeter a year by the end of the century, faster than coastal defenses can build. This scenario poses an existential threat to world’s coastal populations, with 230 million people already living within 1 meter above current sea level.
The researchers found that even just 20 centimeters of sea level rise by 2050 would lead to global flood damages of at least $1 trillion a year for the world’s largest coastal cities. The scientists emphasized that every fraction of a degree of global heating avoided still matters, as it slows sea level rise and gives more time to prepare.
The researchers suggest that the “safe limit” temperature for ice sheets is around 1°C or lower, with sea level rise of at least 1-2 meters now inevitable. In the UK, just 1 meter of sea level rise would see large parts of the Fens and Humberside below sea level.
Developing countries such as Bangladesh would fare worse than rich nations like the Netherlands in adapting to this scenario. The study’s lead author, Durham University’s Prof Chris Stokes, said: “We’re starting to see some of the worst-case scenarios play out almost in front of us.”
Source: https://www.motherjones.com/environment/2025/05/sea-level-rise-will-cause-catastrophic-inland-migration