Greenland ice sheet’s losses have accelerated so fast since the 1990s it is now shedding more than seven times as much ice each year, according to 89 scientists who use satellites to study the area.

The sheet’s total losses nearly doubled each decade, from 33 billion tons per year in the 1990s to an average now of 254 billion tons annually. Since 1992, nearly 4 trillion tons of Greenland ice have entered the ocean, the new analysis found, equivalent to roughly a centimeter of global sea-level rise.

While a centimeter may not sound like much, that uptick is already affecting millions.

“Around the planet, just 1 centimeter of sea-level rise brings another 6 million people into seasonal, annual floods,” said Andrew Shepherd, a University of Leeds professor who co-led the massive collaboration with NASA researcher Erik Ivins.