The Greenland ice sheet appears more vulnerable to global warming than previously thought, as a small increase in temperature could melt it completely and lead to a catastrophic sea level rise, claims a new study. The ice sheet may lose its ability to grow once global warming reaches 1.6 degrees Celsius above the pre-industrial levels, said the study published in the journal Nature Climate Change.

Earlier research had put that threshold a little higher, with a best estimate of 3.1 degrees Celsius. To put these numbers in perspective, climate scientists said the Earth’s surface has already warmed by more than 0.7 degrees Celsius since the Industrial Revolution, when humans began pumping out large amounts of greenhouse gases, particularly carbon dioxide.

According to researchers, the Greenland ice sheet matters because the ice it contains would substantially raise sea level if it melted, LiveScience reported.

Antarctica, too, is covered in ice and could contribute to sea-level rise. Warming is also expected to melt other pockets of ice around the world.