Why are sea levels rising everywhere except Greenland?

While sea levels continue to rise almost everywhere in the world, there is one place where the opposite will happen: Greenland. There, according to a new study, the sea is set to lower. And the cause is precisely melting ice. How is this possible?

The study, published in Nature Communications, shows that sea levels around Greenland could lower by almost 0.9 meters by 2100 in a low-emissions scenario, and even by 2.5 meters in a high-emissions scenario.

This is a paradox in appearance only, which shows just how complex the Earth system is, and how the effects of the climate crisis are not the same everywhere.

The first key factor is the so-called glacial isostatic rebound. The Greenland ice sheet - up to a kilometer and a half thick and covering 80% of the island - loses around 200 billion tons of ice a year.

When such an enormous mass is lightened, the earth's crust beneath begins to rise.

"It's like a memory foam mattress when you get up," explains Lauren Lewright, first author of the study and a doctoral student in geophysics at Columbia Climate School's Lamont-Doherty Earth Observatory. The less weight there is on top, the more the earth rises. And when the land rises, the sea, relative to the coast, seems to lower.

Then, there's another element often forgotten in the climate debate: gravity. The great ice caps are not just ice: they are huge masses that physically draw ocean water towards them. As the ice cap loses mass, this gravitational attraction also diminishes.

The result? The water 'moves away' from Greenland. According to the researchers, this effect could explain up to 30% of the predicted drop in sea level around the island.

The robustness of these results is largely due to the method used. The team combined thousands of years of sea-level data, over twenty years of satellite measurements and signals from 57 GPS stations across Greenland.

The comparison between models and actual observations led to an important conclusion: the Earth is responding to ice loss faster than previously thought. This means that the local effects of climate change may manifest themselves earlier - and more strongly - than previous estimates indicated.

Lower sea levels in Greenland are not 'good news'. It's a sign of massive ice loss, which is contributing to rising sea levels elsewhere, endangering coastal cities and millions of people.

This research reminds us of one essential thing: climate change is not uniform. There is no single "global mean sea level" that tells the whole story.

Each region reacts differently, depending on local factors such as geology, ice loss or gravity.

(©GreenMe.it/Translation and adaptation: MP- The Global Nature/Pic: Unsplash)