Seven worst years for polar ice sheet melting occurred in past decade: study

Earth’s polar ice sheets lost 7,560 billion tonnes of ice between 1992 and 2020. | Photo Credit: REUTERS

Scientists report that the seven worst years for polar ice sheets melting and losing ice have occurred during the past decade, with 2019 being the worst year on record.

Combining 50 satellite surveys of Antarctica and Greenland taken between 1992 and 2020, the international team of researchers have found that the melting ice sheets now account for a quarter of all sea level rise, a fivefold increase since the 1990s.

The findings of the team, led by the Northumbria University’s Centre for Polar Observations and Modelling, U.K., were published in the journal, Earth System Science Data.

In their study, the researchers found that earth’s polar ice sheets lost 7,560 billion tonnes of ice between 1992 and 2020, which is equivalent to an ice cube that would be 20 km in height.

They also found that the polar ice sheets have together lost ice in every year of the satellite record, and the seven highest melting years have occurred in the past decade.

Melting year

The satellite records showed that 2019 was the record melting year when the ice sheets lost a staggering 612 billion tonnes of ice.

They said that the loss, driven by an Arctic summer heatwave, led to record melting from Greenland peaking at 444 billion tonnes that year.

Antarctica was found to have lost 168 billion tonnes of ice, the sixth highest on record, due to the continued speedup of glaciers in West Antarctica and record melting from the Antarctic Peninsula. The East Antarctic Ice Sheet was found to remain close to a state of balance, as it had throughout the satellite era.

Melting of the polar ice sheets has found to cause a 21 millimetres (mm) rise in global sea level since 1992, almost two thirds, or 13.5 mm, of which has originated from Greenland and one third, or 7.4 mm, from Antarctica.

Fivefold increase

The researchers say that there has been a fivefold increase in melting since the early 1990s. While ice sheet melting accounted for only a small fraction (5.6% of sea level rise), they are now responsible for more than a quarter (25.6% of all sea level rise).

“After a decade of work, we are finally at the stage where we can continuously update our assessments of ice sheet mass balance as there are enough satellites in space monitoring them,” said Andrew Shepherd, head of the Department of Geography and Environmental Sciences, Northumbria University.