THE FINANCE – Global ice loss increases at its peak

FINANCE – The rate at which ice is disappearing across the planet is accelerating, according to a new study funded by the Natural Environment Research Council.

The findings also show that 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.
The research is the first of its kind to study global ice loss using satellite data.

Increasing ice loss

Scientists led by the University of Leeds have found that the rate of ice loss from Earth has risen dramatically within the last three decades, from 0.8 trillion tonnes per year in the 1990s to 1.3 trillion tonnes per year by 2017 .

Global ice melting is raising sea levels, increasing the risk of flooding for coastal communities, and threatening the destruction of natural habitats on which wildlife depends.

The findings of the research team, which includes the University of Edinburgh, University College London and data scientists Earthwave, are published in the journal European Geoscience Union The Cryosphere.

Endangered natural habitats

The research shows that, overall, there has been a 65% increase in the rate of ice loss over the 23-year study. This is largely driven by a sharp increase in losses from the polar ice sheets in Antarctica and Greenland.

Lead author Dr Thomas Slater, Research Fellow at the Leeds Center for Polar Observation and Modeling, said:

Although all the areas we studied lost ice, losses from the Antarctic and Greenland ice sheets were the fastest.

The ice sheets now follow the worst-case climate warming conditions imposed by the Intergovernmental Panel on Climate Change. Sea level rise on this scale will have a devastating effect on coastal communities in this century.

Dr. Slater said the study was the first of its kind to study the disappearing ice on Earth, using satellite observations.

He said:

Over the last three decades, there has been a major international effort to understand what is happening to individual parts of the Earth’s ice system, transformed by satellites that allow us to monitor regularly. on the large unstable areas where ice is found.

Our study is the first to combine these efforts and look at the missing ice from the entire planet.

International cooperation

The study covers 215,000 mountain glaciers scattered around the planet, the polar ice sheets in Greenland and Antarctica, the ice shelves floating around Antarctica, and moving sea ice in the -Artic and the South Seas.

Rising atmospheric temperatures have been a major cause of declining Arctic sea ice and mountain glaciers around the globe, and rising sea temperatures are melting the Antarctic ice sheet. For the Greenland ice sheet and Antarctic ice shelves, ice loss was triggered by a combination of rising ocean and atmospheric temperatures.

During the study period, all ice sections were lost, but the largest losses came from Arctic Ocean ice (7.6 trillion tons) and Antarctic ice shelves (6.5 trillion tons), both of which floated on the pole oceans.

Arctic warming

Dr Isobel Lawrence, Research Fellow at the Leeds Center for Polar Observation and Modeling, said:

Loss of sea ice does not directly contribute to sea level rise but has an indirect effect. One of the main responsibilities of Arctic sea ice is to expose solar radiation back into space that will help keep the Arctic cool.

As sea ice erodes, more ocean energy is absorbed by the oceans and atmosphere, causing the Arctic to warm faster than anywhere else on the planet.

Not only does this accelerate the melting of sea ice, it also exacerbates the melting of glaciers and ice sheets that cause sea levels to rise.

Rising global sea levels

Half of all losses came from land-based ice – including 6.1 trillion tonnes from mountain glaciers, 3.8 trillion tonnes from the Greenland ice sheet, and 2.5 trillion tonnes from the Antarctic ice sheet. These losses have raised global sea levels by 35 millimeters.

It is estimated that for every centimeter of sea level rise, around a million people are at risk of being evicted from low-lying homes.

Despite storing just 1% of the Earth’s total ice mass, glaciers have contributed nearly a quarter of the world’s ice loss over the study period, with all glacier areas across the world is losing ice.

Co-author of the report and PhD researcher Inès Otosaka, also from the Leeds Center for Pole Observation and Modeling, said:

As well as contributing to average sea level rise, glaciers are also vital as a freshwater resource for local communities.

Glaciers around the world are therefore of paramount importance at local and global levels.

Just over half (58%) of the ice loss was from the northern hemisphere, and the remainder (42%) was from the southern hemisphere.