Greenland and Antarctica ice losses reach unprecedented levels

By Mark Waghorn via SWNS

The seven worst years for polar ice sheet melting on record all occurred in the past decade, according to new research.

They lost 7.6 billion tonnes between 1992 and 2020 - equivalent to a giant 12-mile-high cube.

Swelling oceans are flooding coasts across the planet. If the phenomenon continues at the same pace, sea levels could rise nearly a foot by the end of the century.

Lead author Dr. Ines Otosaka, from the University of Leeds, said: "Ice losses from Greenland and Antarctica have rapidly increased over the satellite record and are now a major contributor to sea level rise."

They are now responsible for a quarter of the global total - five times more than 30 years ago.

Dr. Otosaka said: "All this has profound implications for coastal communities around the world and their risk of being exposed to flooding and erosion.

"It is really important we have robust estimates for the future contribution to sea-level rise from the ice sheets so we can go to these communities and say, 'Yes, we understand what is happening and we can now start to plan mitigations'."

She added: "Continuously monitoring the ice sheets is critical to predict their future behaviour in a warming world and adapt for the associated risks that coastal communities around the world will face."

The worst year was 2019 when ice sheets lost a staggering 612 billion tonnes - the result of an exceptional summer heat wave in the Arctic.

It is the third assessment from the Ice Sheet Mass Balance Intercomparison Exercise (Imbie) which uses data collected by NASA and ESA (European Space Agency).

Co-author Professor Andrew Shepherd, of Northumbria University, said: "We are finally at the stage where we can continuously update our assessments of ice sheet loss as there are enough satellites in space monitoring them, which means that people can make use of our findings immediately."

Melting in Antarctica has been happening mainly in its peninsula that extends towards South America and in the west where warmer waters are reducing the ice margin.

Shepherd said: "Accelerating ice sheet losses mean we are looking in the next decade at a marked rise in the rate of sea level rise.

"In past decades, it has been about 3mm a year. Soon, we will see 4mm, 5mm, 6mm per year. This will be a big psychological change from what we have been used to."

The international team combined 50 satellite surveys of Antarctica and Greenland taken between 1992 and 2020 to calculate the effect of climate change.

Ice caps can be reliably measured from space by tracking changes in their volume, gravitational pull or flow. The study shows they lost ice in every year.

It has pushed up sea levels by nearly an inch (21mm) during the period - almost two-thirds due to melting in Greenland with the rest resulting from Antarctica.

Added Dr. Diego Fernandez, head of research and development at ESA: "This is another milestone in the IMBIE initiative and represents an example of how scientists can coordinate efforts to assess the evolution of ice sheets from space offering unique and timely information on the magnitude and onset of changes.

"The new annual assessments represent a step forward in the way IMBIE will help to monitor these critical regions, where variations have reached a scale where abrupt changes can no longer be excluded."

The study is in the journal Earth System Science Data with results also publicly available on the British Antarctic Survey website.