Iceland is home to more than 400 glaciers, but that number no longer includes Okjökull, a glacier that scientists say was "killed" by climate change. One hundred years ago, the glacier covered 15 square kilometers (5.8 square miles) of Ok Mountain, a shield volcano. It's now just 1 square kilometer (0.62 square miles) in size and less than 15 meters (49 feet) deep, and scientists no longer consider it a glacier.

To commemorate the “death” of Okjökull, researchers and glaciologists will unveil a plaque on August 18 at Borgarfjörður, Iceland, to serve as a warning for the future, The Guardian reports. Icelandic author Andri Snaer Magnason wrote the plaque’s ominous words, embossed in Icelandic and English:

A Letter to the Future
Ok is the first Icelandic glacier to lose its status as a glacier.
In the next 200 years all our glaciers are expected to follow the same path.
The monument is to acknowledge that we know what is happening and what needs to be done.
Only you know if we did it.”

The text also notes the highest concentration of the greenhouse gas carbon dioxide in Earth's atmosphere ever reached: 415 parts per million, a record set in May 2019. According to meteorologists, that CO2 level is higher than at any time in last several million years, raising average temperatures across the globe and putting all life on Earth at risk. Global warming causes Icelandic glaciers to lose 11 billion tons of ice every year—and sometimes reveals dead bodies.

On the day before the ceremony, a 2018 documentary filmed about the glacier, Not Ok, will screen in Reykjavik, Iceland. As part of the August 18 ceremony, people are encouraged to partake in the Un-glacier Tour II, a hike on Ok to see the remains of the glacier before it completely disappears. The tour is “meant to be a reckoning with glacial demise as well as a celebration of glacial life.”

Not Ok Trailer from Cymene Howe on Vimeo.

June 2019 was the hottest month on record, and by 2200, scientists predict that all of Iceland’s glaciers will succumb to the same fate as Ok "unless we act now to radically curtail greenhouse gas emissions,” Dominic Boyer, a Rice University anthropologist and co-producer of Not Ok, told The Guardian.

[h/t The Guardian]