REYKJAVIK (AFP) - Iceland is planning to mark the passing of Okjokull, its first glacier lost to climate change which threatens some 400 others on the subarctic island.

On Aug 18, a plaque will be unveiled to Okjokull - which translates to "OK glacier" - in the west of Iceland, local researchers and their peers at Rice University in the United States, who initiated the project, said on Monday (July 22).

"This will be the first monument to a glacier lost to climate change anywhere in the world," Associate Professor Cymene Howe, of Rice University's anthropology department, said in a statement.

"By marking OK's passing, we hope to draw attention to what is being lost as Earth's glaciers expire," Prof Howe added.

The researchers hope that the memorial, entitled "A letter to the future", will raise awareness about the decline of glaciers and the effects of climate change.

"In the next 200 years all our glaciers are expected to follow the same path. This monument is to acknowledge that we know what is happening and what needs to be done. Only you know if we did it," the plaque reads.

It is also labelled "415ppm CO2", referring to the record level of carbon dioxide measured in the atmosphere last May.

Glaciologists stripped Okjokull of its glacier status in 2014, a first for Iceland.

In 1890, the glacier ice covered 16 square kilometres but by 2012, it measured just 0.7 sq km, according to a report from the University of Iceland from 2017.

"To have the status of a glacier, the mass of ice and snow must be thick enough to move by its own weight. For that to happen the mass must be approximately 40m to 50m thick," geologist Oddur Sigurdsson told Agence France-Presse.

Iceland's Vatnajokull National Park, which was added to Unesco's World Heritage List in early July, is home to, and named after, the largest ice cap in Europe.

According to a study published by the International Union for the Conservation of Nature (IUCN) in April, nearly half of the world's heritage sites could lose their glaciers by 2100 if greenhouse gas emissions continue at the current rate.

"These bodies of ice are the largest freshwater reserves on the planet and frozen within them are histories of the atmosphere," Prof Howe said.