Research by Abu Dhabi scientists sheds light on why Antarctica is melting

Researchers in the UAE have released findings that could help scientists better understand the factors that are causing Antarctic ice to melt.

Two studies led by scientists at Khalifa University in Abu Dhabi shed light on a subject that is of critical importance to the future of the planet.

“In our studies, we identified the atmospheric processes that are triggering and contributing to the ice melt,” Diana Francis, head of Khalifa University's Environmental and Geophysical Sciences Lab and author of the studies, told The National.

She said that these processes have been increasing in frequency and intensity since 2000, with the causes of both attributed to warmer global temperatures.

“Antarctica is far from our region but ultimately the ice melt there would impact the sea-level rise globally and especially coastal countries like the UAE,” Dr Francis added.

Antarctica holds about 60 per cent of the freshwater in the world and about 90 per cent of Earth's ice.

At over 14 million square kilometres and 2km thick, the Antarctic ice sheet is the biggest ice block in the world.

One of the new studies looks at the Pine Island Glacier, which flows into a bay in West Antarctica.

Pine Island is Antarctica's fastest-melting glacier, accounting for a quarter of its ice loss.

Dr Francis said its melting could “destabilise the whole West Antarctica ice sheet”.

The study looked at how Foehn winds are contributing to the melting of the glacier.

Foehn winds are dry and hot winds that form on the downslopes and the lee side – the side sheltered from the prevailing wind – of a mountain.

Dr Francis said the terrain surrounding the Pine Island Glacier is elevated, meaning that the glacier is often subject to Foehn events.

“Climate change has been identified as a major contributor to the Pine Island Glacier fast melt through both warmer waters, which melt the ice from below, and from a warmer and more moist atmosphere and Foehn events, as highlighted in our study,” she said.

The study is being published in the journal The Cryosphere, the cryosphere being the parts of the Earth’s surface that consist of frozen water.

According to data published by Nasa, the Antarctic ice sheet overall is losing about 150 billion tonnes of ice per year.

Research published in 2020 suggests that even if the world meets the goals of the Paris Agreement on climate change, Antarctic ice melting could raise sea levels by 2.5 metres.

While this would happen on a time scale stretching into the next century, the effects would not be reversed even by a fall in temperatures.

Aside from the impacts of coastal countries and cities through sea-level rise, Dr Francis said that the other main impact of land ice melt in the polar regions would be on ocean circulation and currents.

Freshwater from the melting of ice into the southern ocean can alter ocean circulation and slow down a process known as abyssal ocean overturning. The abyssal zone of the oceans is the pitch-black layer that lies between 4,000 metres and 6,000 metres beneath the surface.

Abyssal ocean overturning is vital to the global ocean circulations that move nutrients, carbon, oxygen and heat around the world.

A recent study by other scientists in the journal Nature suggested that Antarctic meltwater could cause changes to the abyssal ocean “that could last for centuries”.

The other new paper by the Khalifa University scientists and their co-researchers, published in Climate Dynamics, analysed the Terra Nova Bay polynya. A polynya is an area of open water within sea ice, and Terra Nova Bay lies in East Antarctica.

An examination of data available so far did not find any trends in polynya occurrence related to climate change, but Dr Francis said that alterations in circulation driven by changes to the climate were “set to favour more frequent polynya events”.

Aside from being covered by an enormous ice sheet, Antarctica is surrounded by sea ice, which reaches its greatest extent in September, when winter in the southern hemisphere ends, and its lowest extent in February.

Between 1979 and 2014, there was a roughly 1 per cent increase in Antarctic sea ice each decade, according to Nasa, but from 2016 onwards, there have been “significant decreases”.

Aside from the ice sheet that covers Antarctica, the other major ice sheet in the world covers Greenland. This is losing ice at a rate of about 270 billion tonnes a year – an even faster pace than that recorded at the Antarctic ice sheet.