Greenland and Antarctica Have Lost 11.3 Trillion Tonnes of Ice in 50 Years, Study Finds

Greenland and Antarctica have collectively lost 11.3 trillion tonnes of ice since the 1970s, resulting in a global sea level rise of more than 1.1 inches (3 cm), according to a comprehensive new study.

The international team of polar scientists utilized data from 42 independent satellite surveys, spanning 27 satellite missions from the 1970s to 2023, to compile the most complete picture of ice loss from the two largest ice sheets on Earth. The findings indicate that Greenland's melting ice has raised sea levels by approximately 0.7 inches (1.8 cm), while Antarctica contributed 0.5 inches (1.3 cm) over the period.

The study, published in the journal Scientific Data, found that 84% of the total ice loss was due to glaciers accelerating and discharging more ice into the ocean, with surface melting accounting for the remaining 16%. Lead author Dr. Inès Otosaka of Northumbria University stated that the data, reaching back to the 1970s, reveals how ice sheets have changed over half a century and highlights that the long-term trend is driven by the dynamic response of these ice sheets to a warming ocean.

The rate of ice loss has significantly increased in recent decades. Greenland's ice loss escalated from about 60 billion tonnes per year in the 1980s to 264 billion tonnes in the 2010s, a period marked by extreme summer melt events. Antarctica's rate of loss saw a similar surge, from around 48 billion tonnes annually in the 1980s to 202 billion tonnes in the 2010s, with ocean melting of its outlet glaciers being the primary driver.

While the most recent years, 2020-2023, showed a temporary slowdown in ice loss due to record snowfall in East Antarctica and milder summers in Greenland, scientists caution that these are short-term fluctuations and not a reversal of the overall trend. Professor Andrew Shepherd, a co-lead author, emphasized that even a 3 cm sea level rise puts an additional six to nine million people at risk of coastal flooding and erosion.

Globally, average sea levels have risen by 0.14 inches (3.64 millimeters) per year since 1999, totaling 3.6 inches (9.38 cm) over the past 26 years. About 30% of this increase is attributed to ocean expansion due to warming, while the remaining 70% primarily comes from melting glaciers and ice sheets. Recent satellite data shows an acceleration in this rise after 2012, reaching 4.1 mm per year.

Dr. Diego Fernández, Head of the Science Section at the European Space Agency (ESA), underscored the critical role of satellites in monitoring ice sheets and evaluating climate change models. He stressed the importance of maintaining long-term data records from missions like CryoSat-2 and the Sentinels for future projections.

Separate research cited in the study warns of more severe consequences, with one projection indicating that rising sea levels could inundate 1.7 million homes in the UK by 2300, rendering parts of the country uninhabitable. Computer models suggest that areas like the Wash, Humber Estuary, parts of Norfolk, and the northwest coastline are particularly vulnerable to future coastal flooding. Densely populated cities, including significant portions of west London, could also face submersion.