Seven of the worst years for polar glacier melt and ice loss have occurred over the past decade, with 2019 being the worst year on record, according to new research.
Melting ice sheets now account for a quarter of all sea level rise a fivefold increase since the 1990s according to IMBIE, an international team of researchers who combined 50 satellite surveys of Antarctica and Greenland between 1992 and 2020.
Global warming is melting the polar ice caps, raising sea levels and coastal flooding around our planet. Ice loss from Greenland and Antarctica can now be reliably measured from space by monitoring changes in their volume, gravity or ice flow.
NASA and the European Space Agency (ESA) and in 2011 awarded funding to the Ice Sheet Mass Balance Intercomparison Exercise (IMBIE) to compile a satellite record of polar ice sheet melting. The data collected by the team is widely used by leading organizations, including the Intergovernmental Panel on Climate Change (IPCC).
Melting polar ice caps and ice loss
In their latest assessment, the IMBIE team which is led by the Center for Polar Observation and Modeling at Northumbria University combined 50 satellite surveys of Antarctica and Greenland to determine their rate of ice melt.
They found that the Earth’s polar ice sheets lost 7,560 billion tons of Polar ice between 1992 and 2020 the equivalent of an ice cube that would be 20 kilometers high.
The polar ice sheets collectively lost ice in every year of the satellite record, and the seven years with the highest melting occurred in the last decade. Satellite records show that 2019 was a record melting year, with the ice sheets losing a staggering 612 billion tonnes of ice.
This loss was caused by Arctic summer heat, which led to record melting from Greenland, which peaked at 444 billion tons that year. Antarctica has lost 168 billion tonnes of ice the sixth most on record due to the continued acceleration of glaciers in West Antarctica and record melting from the Antarctic Peninsula.
Melting of the polar ice sheets has caused global sea level
Melting of the polar ice sheets has caused global sea level to rise by 21 mm since 1992, with nearly two-thirds (13.5 mm) coming from Greenland and one-third (7.4 mm) from Antarctica.
In the early 1990s, ice sheet melting accounted for only a small fraction (5.6%) of sea level rise quarter (25.6%) of all sea level rise. If the ice sheets continue to lose mass at this rate, the IPCC predicts they will contribute 148 to 272 mm to global mean sea level by the end of the century.
Professor Andrew Shepherd, Head of Geography and Environmental Sciences at Northumbria University and founder of IMBIE, said: “After ten years of work, we are finally at the stage where we can continuously update our assessment of ice sheet mass balance enough satellites in space to monitor them, which means people can use our findings immediately.”
Over the past few years, ESA and NASA have made great efforts to launch new satellite missions capable of monitoring polar regions. The IMBIE project has used this to produce more regular updates, and for the first time it is now possible to map polar ice sheet losses each year.
Polar Ice loss from Antarctica and Greenland
This third assessment by the IMBIE team, funded by ESA and NASA, involved a team of 68 polar scientists from 41 international organizations using measurements from 17 satellite missions, including for the first time from the gravity mission GRACE-FO. Importantly, it aligns records of ice loss from Antarctica and Greenland using the same methods and covering the same time period. The assessment will now be updated annually to ensure the scientific community has the latest estimates of polar ice loss.
Dr Diego Fernandez, Head of Research and Development at ESA, said: “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 size.” and the onset of changes.
“The new annual assessments represent a step forward in the way IMBIE will help monitor these critical regions where variation has reached a scale where sudden changes can no longer be ruled out.”
Written by: Vaishali verma
