11.3 trillion tonnes of ice gone

Greenland and Antarctica have lost 11.3 trillion tonnes of ice since 1979, raising global sea levels by more than 1.1 inches. An international team of polar scientists combined 42 satellite surveys spanning 27 missions to produce the most complete picture of ice loss from the world's two largest ice sheets.

Greenland's contribution to sea rise

Melting ice in Greenland has driven sea levels up by 0.7 inches since 1976. Greenland's rate of ice loss rose from around 60 billion tonnes a year in the 1980s to 264 billion in the 2010s, a decade marked by repeated extreme summer melt events.

Antarctica's share of the rise

Antarctica has contributed 0.5 inches to sea level rise since 1976. Its rate of ice loss rose from around 48 billion tonnes a year in the 1980s to 202 billion in the 2010s, with all losses caused by ocean melting of outlet glaciers.

Glaciers speeding up, not just melting

84 per cent of ice loss came from glaciers flowing faster into the ocean, while only 16 per cent resulted from surface melting. This shows the long-term trend is driven by the dynamic response of ice sheets to a warming ocean.

“More than four, fifths of the ice lost was discharged into the ocean by faster, flowing glaciers, rather than melted at the surface”

Millions now at risk of flooding

Scientists warn that 1.1 inches of sea level rise puts 6 to 9 million additional people at risk of coastal flooding and erosion. This risk will continue to grow as climate change accelerates ice loss.

“Three centimetres of sea level rise may sound small, but that puts another six to nine million people at risk of coastal flooding and erosion.”

Recent slowdown is temporary

The years 2020 to 2023 showed a temporary slowdown in ice loss. Record snowfall over East Antarctica and milder Greenland summers reduced losses, but scientists warn these are short-term fluctuations, not a reversal of the long-term trend.

Global sea level accelerating faster

Globally, average sea level has risen 0.14 inches per year since 1999, totalling 3.6 inches over 26 years. However, this increase rapidly accelerated after 2012, jumping to 4.1 millimetres per year.

Ocean warming drives most of the rise

About 30 per cent of sea level increase comes from the ocean expanding as it warms. The remaining 70 per cent mainly comes from melting glaciers and ice sheets, making ice loss the dominant factor.

Ice sheets key to future predictions

The findings underline ice sheets' central role in future sea level rise. Their response to a warming climate is now the single largest source of uncertainty in sea level projections, making accurate monitoring critical.

Satellites essential for monitoring

The study relied on data from CryoSat-2 and Sentinel satellites to track ice loss. Scientists say sustaining these missions and maintaining long-term ice sheet climate records is critical for the decades ahead.

1.7 million UK homes at risk by 2300

A separate study found that rising sea levels could plunge 1.7 million British homes underwater by 2300. Areas like the Wash, Humber Estuary, Norfolk, and parts of London face particular risk from coastal flooding.

Southeast England faces worst impact

Researchers identified the Wash and Humber Estuary as flooding hotspots. Large parts of the Southeast, Norfolk, northwest coastline, and west London will be submerged, with extensive flooding around Blackpool and Liverpool.

Thwaites Glacier could raise seas 10 feet

Global sea levels could rise as much as 10 feet if the Thwaites Glacier in West Antarctica collapses. This could submerge major cities including New York, Sydney, London, Shanghai, and low-lying nations like the Maldives.

US East Coast faces tidal flooding surge

A 2014 study of 52 US communities found tidal flooding will dramatically increase along the East and Gulf Coasts. By 2030, more than half are projected to experience at least 24 tidal floods per year, with 20 communities seeing flooding triple or more.

Mid-Atlantic hotspot for flooding

The mid-Atlantic coast is expected to see the greatest increases in flood frequency. Annapolis and Washington DC can expect more than 150 tidal floods a year, while several New Jersey locations could see 80 or more.

Two metre rise would reshape UK by 2040

A 2016 study found that a two metre sea level rise by 2040 would see large parts of Kent almost completely submerged. Portsmouth, Cambridge, Peterborough, Hull, Scunthorpe, and Grimsby would also experience intense flooding.

Population relocation may become necessary

Researchers warn that worst-case sea level rise outcomes would pose massive challenges for the UK in coming centuries. Large-scale movement of populations and settlements away from the coast may become necessary to protect communities.

“The worst, case sea, level rise outcomes would pose massive challenges for the UK in the coming centuries and the need for large, scale movement of populations and settlements away from the coast.”