A new study based on satellite data collected since the 1970s recorded significant losses of polar ice in Greenland and Antarctica — the regions home to Earth’s two largest ice sheets — contributing to a rise in global sea levels, UNN reports, citing Reuters.
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Between 1979 and 2023, according to data from 27 satellite missions, Greenland and Antarctica lost a combined 11.3 trillion tonnes of ice, causing global sea levels to rise by 1.24 inches (3.14 cm).
This study, which used the longest satellite data record to date on changes in ice sheets to provide the most comprehensive picture of ice loss in Greenland and Antarctica, was conducted by the Ice Sheet Mass Balance Inter-comparison Exercise team.
According to scientists, the findings provide new evidence of the consequences of human-caused global climate change.
"To better visualize the scale of this enormous figure: 11.3 trillion tonnes of ice is enough to form a cube 23 kilometers (14.3 miles) high," said climatologist Inès Otosaka of Northumbria University (England), the lead author of the study published Wednesday in the journal Scientific Data.
Of the total ice loss recorded in the study, about 60% occurred in Greenland and 40% in Antarctica, despite the fact that Greenland’s area is only about one-eighth the area of Antarctica.
"When ice sheets melt, this contributes to rising global sea levels. And for every additional centimeter of sea-level rise, 2 to 3 million people are put at risk of annual coastal flooding. At present, ice sheets are one of the main contributors to sea-level rise, accounting for about 25% of the total increase in this indicator," Otosaka explained.
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"We extended the time span of our satellite data to cover the period since the 1970s, and this confirms that ice loss began in the 1990s and has increased since then. Our estimate indicates that the rate of ice loss quadrupled between the 1980s and the 2010s," Otosaka added. The study recorded a slowdown in the rate of ice loss between 2020 and 2023, although scientists said this was likely a short-term fluctuation rather than a change in the long-term trend. They noted that exceptionally heavy snowfall in East Antarctica provided enough ice accumulation to offset some of the losses from glaciers in other parts of the continent, while a relatively mild summer in Greenland significantly reduced surface ice melting.
About 84% of the ice loss was caused by glaciers rapidly flowing into the ocean, rather than by surface ice melting; this indicates that the long-term trend is driven by the ice sheets’ response to ocean warming, Otosaka explained.
The researchers noted that although the overall sea-level rise resulting from ice loss in Greenland and Antarctica may appear insignificant, it puts between 6 and 9 million people worldwide at risk of coastal flooding and soil erosion.
"These findings have important implications for coastal development planning and demonstrate the urgent need to develop plans to protect coastal communities around the world from the consequences of melting ice sheets," Otosaka concluded.