Global ice loss increases at record rate
Ice is disappearing from across the entire planet at an accelerating rate, according to new research.
The Earth lost 28 trillion tonnes of ice between 1994 and 2017, the equivalent of a 100 meter thick sheet of ice, covering the whole of the UK, experts say.
The study – led by the University of Leeds and including scientists from Edinburgh, University College London and data specialists Earthwave – is the first to survey global ice loss using satellite data.
The team found that the rate of ice loss from the Earth has increased markedly within the past three decades, from 0.8 trillion tons per year in the 1990s to 1.3 trillion tons per year by 2017.
There has been a 65 per cent increase in the rate of ice loss over the 23-year survey, the study found. This has been mainly driven by steep rises in losses from the polar ice sheets in Antarctica and Greenland.
Ice melt across the globe raises sea levels, increases the risk of flooding to coastal communities, and threatens to wipe out the natural habitats on which wildlife depend.
The ice sheets are now following the worst-case climate warming scenarios set out by the Intergovernmental Panel on Climate Change. “Over the past three decades there’s been a huge international effort to understand what’s happening to individual components in Earth’s ice system, revolutionised by satellites which allow us to routinely monitor the vast and inhospitable regions where ice can be found. Our study is the first to combine these efforts and look at all the ice that is being lost from the entire planet.
The increase in ice loss has been triggered by warming of the atmosphere and oceans, which have warmed by 0.26°C and 0.12°C per decade since the 1980s respectively. The majority of all ice loss was driven by atmospheric melting (68 %), with the remaining losses (32%) being driven by oceanic melting.
The survey examined 215,000 mountain glaciers around the planet, the polar ice sheets in Greenland and Antarctica, the ice shelves floating around Antarctica, and sea ice drifting in the Arctic and Southern Oceans.
Rising atmospheric temperatures have been the main driver of the decline in Arctic sea ice and mountain glaciers across the globe, while rising ocean temperatures have increased the melting of the Antarctic ice sheet. For the Greenland ice sheet and Antarctic ice shelves, ice losses have been triggered by a combination of rising ocean and atmospheric temperatures.
During the survey period, every category lost ice, but the biggest losses were from Arctic Sea ice – 7.6 trillion tons – and Antarctic ice shelves – 6.5 trillion tons – both of which float on the polar oceans.
Experts from the University of Edinburgh’s School of GeoSciences contributed to the study by analysing the health of land based glaciers in the Arctic, the Gulf of Alaska and the Himalayas.
The team used satellite altimetry – a technology that uses radio waves to measure the topography of the land and ocean. The resulting data tracked glaciers thinning in difficult to monitor high-mountain regions, ensuring a complete assessment of Earth’s ice imbalance.
This is the first ever compilation of ice loss from all components of the frozen planet. The numbers are staggering and cannot be ignored.
Co-author, Livia Jakob, Edinburgh alumni and Director of Earthwave, said:
“Most of the ice loss takes places in remote regions. Let’s hope that this study helps to realise the scale of the transformation taking place before our very eyes.”
The researched is published in the European Geosciences Union’s journal, The Cryosphere and funded by UK Natural Environment Reaserch Council and the European Space Agency.