Alarming report: Earth has lost 28 trillion tons of ice since 1994

Alarming report: Earth has lost 28 trillion tons of ice since 1994

Scientists ‘stunned’ say there is little doubt that global warming is to blame for global ice loss.

A total of 28 trillion tons of ice have disappeared from the Earth's surface since 1994. That is a surprising conclusion from scientists in the UK who have analyzed satellite studies of the planet's poles, mountains and glaciers to measure how much coverage of Ice was lost due to global warming caused by increased greenhouse gas emissions.

The scientists, based at the Universities of Leeds and Edinburgh and University College London, describe the level of ice loss as "staggering" and caution that their analysis indicates that rising sea levels, triggered by melting glaciers and ice caps, could reach one meter by the end of the century.

"To put that in context, every inch of sea level rise means that around a million people will be displaced from their lowlands," said Professor Andy Shepherd, director of the Center for Polar Modeling and Observation at the University of Leeds. .

Scientists also warn that melting ice in these amounts is now seriously reducing the planet's ability to reflect solar radiation back into space. The white ice is disappearing and the dark sea or exposed soil below it absorbs more and more heat, further increasing global warming.

Additionally, cold freshwater rising from glaciers and melting ice sheets is causing major disruptions to the biological health of Arctic and Antarctic waters, while loss of glaciers in mountain ranges threatens to wipe out sources. of fresh water that local communities depend on.

“In the past, researchers have studied individual areas, such as Antarctica or Greenland, where the ice is melting. But this is the first time anyone has observed all the ice that is disappearing from all over the planet, ”Shepherd said. "What we have found has amazed us."

The level of ice loss revealed by the group matches the worst-case-scenario predictions outlined by the Intergovernmental Panel on Climate Change (IPCC), it added.

The group analyzed satellite studies of glaciers in South America, Asia, Canada and other regions; sea ​​ice in the Arctic and Antarctica; ice sheets covering the ground in Antarctica and Greenland; and ice shelves emerging from the Antarctic continent into the sea. The study covered the years 1994 to 2017.

The researchers' conclusion is that all regions have suffered devastating ice sheet reductions in the past three decades, and these losses continue.

"To put into context the losses we have already experienced, 28 trillion tonnes of ice would cover the entire UK surface in a 100 meter thick layer of frozen water," added group member Tom Slater from the University of Leeds. . "It's just mind blowing."

As for the cause of these staggering losses, the group is adamant: "There is no doubt that the vast majority of ice loss on Earth is a direct consequence of global warming," they state in their review article, which publishes online in the MagazineCryosphere Discussions.

"On average, the temperature of the planetary surface has increased by 0.85 ° C since 1880, and this signal has been amplified in the polar regions," they say. As a result, both sea and atmospheric temperatures have risen, and the resulting double blow has triggered the catastrophic ice losses discovered by the group.

In the case of the melting ice sheet in Antarctica, the increase in sea temperature has been the main driver, while the increase in atmospheric temperature has been the cause of the loss of ice from continental glaciers such as those of the Himalayas. In Greenland, ice loss has been triggered by a combination of rising sea and atmospheric temperatures.

The team emphasized that not all of the ice that was lost during that period would have contributed to sea level rise. "A total of 54% of the lost ice came from sea ice and ice shelves," said Isobel Lawrence, a researcher at the University of Leeds. “These float on water and their melting would not have contributed to the rise in sea level. The other 46% of the meltwater came from glaciers and ice sheets on the ground, and would have contributed to the rise in sea level ”.

The group's results were published 30 years after the publication of the IPCC's first assessment report, in late August 1990. It described, in clear terms, that global warming was real and was being driven by rising emissions. of greenhouse gases from burning fossil fuels.

Despite warnings from scientists, these emissions have continued to rise as global temperatures continued to rise. According to figures released by the Met Office last week, there was a 0.14 ° C rise in global temperatures between the 1980-89 decade and the 1990-1999 decade, then a 0.2 ° C rise between each. of the following decades. This rate of increase is expected to increase, possibly to around 0.3 ° C per decade, as carbon emissions continue on their upward trajectory.

Video: ICLR Friday Forum: Near-Earth Asteroid Impact December 13, 2019 (November 2021).