HELHEIM GLACIER, Greenland (AP) — This is where Earth’s refrigerator door is left open, where glaciers dwindle and seas begin to rise.

New York University air and ocean scientist David Holland, who is tracking what’s happening in Greenland from both above and below, calls it “the end of the planet.” He is referring to geography more than the future. Yet in many ways this place is where the planet’s warmer and watery future is being written.

It is so warm here, just inside the Arctic Circle, that on an August day, coats are left on the ground and Holland and colleagues work on the watery melting ice without gloves. In one of the closest towns, Kulusuk, the morning temperature reached a shirtsleeve 52 degrees Fahrenheit

The ice Holland is standing on is thousands of years old. It will be gone within a year or two, adding yet more water to rising seas worldwide.

Summer this year is hitting Greenland hard with record-shattering heat and extreme melt. By the end of the summer, about 440 billion tons of ice — maybe more — will have melted or calved off Greenland’s giant ice sheet, scientists estimate. That’s enough water to flood Pennsylvania or the country of Greece about a foot deep.

In just the five days from July 31 to Aug. 3, more than 58 billion tons melted from the surface. That’s over 40 billion tons more than the average for this time of year. And that 58 billion tons doesn’t even count the huge calving events or the warm water eating away at the glaciers from below, which may be a huge factor.

And one of the places hit hardest this hot Greenland summer is here on the southeastern edge of the giant frozen island: Helheim, one of Greenland’s fastest-retreating glaciers, has shrunk about 6 miles since scientists came here in 2005.

Several scientists, such as NASA oceanographer Josh Willis, who is also in Greenland, studying melting ice from above, said what’s happening is a combination of man-made climate change and natural but weird weather patterns. Glaciers here do shrink in the summer and grow in the winter, but nothing like this year.

Summit Station, a research camp nearly 2 miles high and far north, warmed to above freezing twice this year for a record total of 16.5 hours. Before this year, that station was above zero for only 6.5 hours in 2012, once in 1889 and also in the Middle Ages.

This year is coming near but not quite passing the extreme summer of 2012 — Greenland’s worst year in modern history for melting, scientists report.

“If you look at climate model projections, we can expect to see larger areas of the ice sheet experiencing melt for longer durations of the year and greater mass loss going forward,” said University of Georgia ice scientist Tom Mote. “There’s every reason to believe that years that look like this will become more common.”

A NASA satellite found that Greenland’s ice sheet lost about 255 billion metric tons of ice a year between 2003 and 2016, with the loss rate generally getting worse over that period.