A new study has found that the Earth’s ice is melting at a record rate, and that this rate of ice loss is in line with the worst-case scenarios set out by the UN’s Intergovernmental Panel on Climate Change (IPCC). The study, published on 25 January in the journal The Cryosphere, finds that the world has lost 28 trillion tonnes of ice between 1994-2017. Prepared by researchers led by the University of Leeds, the study Earth’s Ice Imbalance, also states that the rate of ice loss has increased from 0.8 trillion tonnes per year in the 1990s to 1.3 trillion tonnes per year in 2017.
Read our assessment of global #ice loss out today in @EGU_TC - Earth is losing ice 65% faster now than it was in the 1990s, at a rate of 1.3 trillion (metric) tonnes per year: https://t.co/3v68e52oA4 pic.twitter.com/ZzMMPsNx8o— Tom Slater (@_tslater) January 25, 2021
This column had covered the study when it was first introduced as a discussion paper in August last year, since when its results have been further refined. The report finds that the majority of ice loss has occurred in the northern hemisphere (58%), with the loss of Arctic sea ice accounting for the largest share of the loss at 7.6 trillion tonnes. However, ice is in retreat everywhere, including the Greenland ice sheet (3.8 trillion tonnes lost), Antarctic ice shelves (6.5 trillion tonnes) and mountain glaciers (6.1 trillion tonnes). “The ice sheets are now following the worst-case climate warming scenarios set out by the Intergovernmental Panel on Climate Change. Sea-level rise on this scale will have very serious impacts on coastal communities this century,” said Thomas Slater from the University of Leeds’ Centre for Polar Observation and Modelling and the lead author of the study.
While the loss of sea ice means that lesser amounts of sunlight is being reflected back into space, the report states that the loss of land-ice (e.g. glaciers and Greenland) has raised global sea levels by 3.5cm. The report also estimates that for every centimetre of sea level rise, a million people living in low-lying areas around the world will be threatened.
Among mountain glaciers, those in High Mountain Asia (including the Himalaya) are losing ice at an alarming rate. The report states that between 1962-2019, High Mountain Asia has seen cumulative glacier mass change worth 97,606 sq km, the third highest in the world, and the highest outside of the polar regions.
It stands to reason that this record rate of ice loss poses a massive threat for India, and South Asia in general. India’s coastal districts and islands are home to over 177 million people, while 670 million people live in High Mountain Asia (50 million in India). Additionally, over 900 million people in South Asia live in the glacier-fed river basins of the Indus, the Ganga and the Brahmaputra.