The Greenland and Antarctic ice sheets are at risk of melting, which could lead to a rise in the sea level by multiple feet and “catastrophic” migration away from coastlines, a new study has highlighted. Researchers have warned that the melting process may continue even if the world manages to keep global warming to within 1.5 degrees Celsius.

The findings were revealed after studying data from satellites, climate models and evidence from the past, from things like ice cores, deep-sea sediments and even octopus DNA.

The scientists discovered that even if the world sustains today’s level of warming at 1.2 degrees Celsius, it would still lead to rapid ice sheet melting and catastrophic sea level rise. It is predicted that global warming could reach up to 2.9 degrees Celsius by 2100.

The Greenland and Antarctic ice sheets together hold water to raise the global sea level by around 213 feet. Since the 1990s, the ice has melted quadrupled, with about 370 billion tons lost each year, and the rate of sea level rise has doubled over the last 30 years.

“You don’t slow sea level rise at 1.5, in fact, you see quite a rapid acceleration,” said Chris Stokes, co-author of the study and glaciologist at Durham University, told CNN.

The study has warned that even a small amount of ice melting could lead to a reshaping of coastlines, displacing hundreds of millions of people and causing severe damage. The world is already starting to witness some of the worst-case scenarios in terms of ice loss.

“There’s very little that we’re observing that gives us hope here,” Stokes said. “The absolute best-case scenario is that sea level rise is slow and steady.”

To avoid this, the researchers urged to cut fossil fuel use sharply. However, the goal is unlikely with countries like the US still using oil, coal, and gas, the scientists say.

“Limiting warming to 1.5 will be a major achievement. It should absolutely be our target, but in no sense will it slow or stop sea level rise and melting ice sheets,” Stokes added.