Thwaites glaciär, Antarktis

Unprecedented data confirms that Antarctica’s most dangerous glacier is melting from below
Källa: https://www.washingtonpost.com/climate-environment/2020/01/30/unprecedented-data-confirm-that-antarcticas-most-dangerous-glacier-is-melting-below

Glaciärer som sträcker sig ut över hav passerar ett område på havsbottnen, en tröskel, där den tappar kontakten med berggrunden och börjar flyta. Där det sker kommer omgivande vatten att kunna transportera in värme och smälta isen underifrån.

The unprecedented research, part of a multimillion-dollar British and U.S. initiative to study the remote Thwaites Glacier, involved drilling through nearly 2,000 feet of ice to measure water temperatures in a narrow cavity where the glacier first connects with the ocean. This is one of the most difficult-to-reach locations on Earth.

Genom att borra 600 meter ner genom isen nåddes tröskeln och vattnets temperatur mättes där till 0°C där havsvatten har en fryspunkt neråt -2°C.

Thwaites is the most worrying glacier in Antarctica because of its size — it is unusually wide, presenting a 75-mile front of ice to the ocean, without any rocks or mountains to hem it in. This means very large volumes of ice could break off and flow uninhibited through this region into the sea.

En 120 km bred flytande istunga som gradvis undermineras av ‘varmt’ vatten och inte hindras av omgivande berg från att brytas loss.

“Is the water moving around and releasing heat to the ice efficiently, is it stagnant instead?” Rignot continued. “Our sense from remote sensing is that it is not stagnant but very actively melting ice. So having temperature measurements in that narrow part is essential.”