mid-1990s, study suggests
FILE PHOTO: Floating ice is seen during the expedition of the
The Greenpeace's Arctic Sunrise ship at the Arctic Ocean
Yereth Rosen
Mon., January 25, 2021, 2:01 a.m.
ANCHORAGE, Alaska (Reuters) - Earth’s ice is melting faster today than in the mid-1990s, new research suggests, as climate change nudges global temperatures ever higher.
Altogether, an estimated 28 trillion metric tons of ice have melted away from the world’s sea ice, ice sheets and glaciers since the mid-1990s. Annually, the melt rate is now about 57 percent faster than it was three decades ago, scientists report in a study published Monday in the journal The Cryosphere.
“It was a surprise to see such a large increase in just 30 years,” said co-author Thomas Slater, a glaciologist at Leeds University in Britain.
While the situation is clear to those depending on mountain glaciers for drinking water, or relying on winter sea ice to protect coastal homes from storms, the world’s ice melt has begun to grab attention far from frozen regions, Slater noted.
Aside from being captivated by the beauty of polar regions, “people do recognize that, although the ice is far away, the effects of the melting will be felt by them,” he said.
The melting of land ice – on Antarctica, Greenland and mountain glaciers – added enough water to the ocean during the three-decade time period to raise the average global sea level by 3.5 centimeters. Ice loss from mountain glaciers accounted for 22 percent of the annual ice loss totals, which is noteworthy considering it accounts for only about 1 percent of all land ice atop land, Slater said.
Across the Arctic, sea ice is also shrinking to new summertime lows. Last year saw the second-lowest sea ice extent in more than 40 years of satellite monitoring. As sea ice vanishes, it exposes dark water which absorbs solar radiation, rather than reflecting it back out of the atmosphere. This phenomenon, known as Arctic amplification, boosts regional temperatures even further.
The global atmospheric temperature has risen by about 1.1 degrees Celsius since pre-industrial times. But in the Arctic, the warming rate has been more than twice the global average in the last 30 years.
Using 1994–2017 satellite data, site measurements and some computer simulations, the team of British scientists calculated that the world was losing an average of 0.8 trillion metric tons of ice per year in the 1990s, but about 1.2 trillion metric tons annually in recent years.
Calculating even an estimated ice loss total from the world’s glaciers, ice sheets and polar seas is “a really interesting approach, and one that’s actually quite needed,” said geologist Gabriel Wolken with the Alaska Division of Geological and Geophysical Surveys. Wolken was a co-author on the 2020 Arctic Report Card released in December, but was not involved with the new study.
In Alaska, people are “keenly aware” of glacial ice loss, Wolken said. “You can see the changes with the human eye.”
Research scientist Julienne Stroeve of the National Snow and Ice Data Center in Boulder, Colorado noted the study had not included snow cover over land, "which also has a strong albedo feedback”, referring to a measure of how reflective a surface is.
The research also did not consider river or lake ice or permafrost, except to say that “these elements of the cryosphere have also experienced considerable change over recent decades.”
(Reporting by Yereth Rosen; Editing by Katy Daigle and Philippa Fletcher)
Our goal is to create a safe and engaging place for users to connect over interests and passions. In order to improve our community experience, we are temporarily suspending article commenting.
World's ice is melting two-thirds faster than in the 1990s
Olivia Rudgard
Mon., January 25, 2021,
Yereth Rosen
Mon., January 25, 2021, 2:01 a.m.
ANCHORAGE, Alaska (Reuters) - Earth’s ice is melting faster today than in the mid-1990s, new research suggests, as climate change nudges global temperatures ever higher.
Altogether, an estimated 28 trillion metric tons of ice have melted away from the world’s sea ice, ice sheets and glaciers since the mid-1990s. Annually, the melt rate is now about 57 percent faster than it was three decades ago, scientists report in a study published Monday in the journal The Cryosphere.
“It was a surprise to see such a large increase in just 30 years,” said co-author Thomas Slater, a glaciologist at Leeds University in Britain.
While the situation is clear to those depending on mountain glaciers for drinking water, or relying on winter sea ice to protect coastal homes from storms, the world’s ice melt has begun to grab attention far from frozen regions, Slater noted.
Aside from being captivated by the beauty of polar regions, “people do recognize that, although the ice is far away, the effects of the melting will be felt by them,” he said.
The melting of land ice – on Antarctica, Greenland and mountain glaciers – added enough water to the ocean during the three-decade time period to raise the average global sea level by 3.5 centimeters. Ice loss from mountain glaciers accounted for 22 percent of the annual ice loss totals, which is noteworthy considering it accounts for only about 1 percent of all land ice atop land, Slater said.
Across the Arctic, sea ice is also shrinking to new summertime lows. Last year saw the second-lowest sea ice extent in more than 40 years of satellite monitoring. As sea ice vanishes, it exposes dark water which absorbs solar radiation, rather than reflecting it back out of the atmosphere. This phenomenon, known as Arctic amplification, boosts regional temperatures even further.
The global atmospheric temperature has risen by about 1.1 degrees Celsius since pre-industrial times. But in the Arctic, the warming rate has been more than twice the global average in the last 30 years.
Using 1994–2017 satellite data, site measurements and some computer simulations, the team of British scientists calculated that the world was losing an average of 0.8 trillion metric tons of ice per year in the 1990s, but about 1.2 trillion metric tons annually in recent years.
Calculating even an estimated ice loss total from the world’s glaciers, ice sheets and polar seas is “a really interesting approach, and one that’s actually quite needed,” said geologist Gabriel Wolken with the Alaska Division of Geological and Geophysical Surveys. Wolken was a co-author on the 2020 Arctic Report Card released in December, but was not involved with the new study.
In Alaska, people are “keenly aware” of glacial ice loss, Wolken said. “You can see the changes with the human eye.”
Research scientist Julienne Stroeve of the National Snow and Ice Data Center in Boulder, Colorado noted the study had not included snow cover over land, "which also has a strong albedo feedback”, referring to a measure of how reflective a surface is.
The research also did not consider river or lake ice or permafrost, except to say that “these elements of the cryosphere have also experienced considerable change over recent decades.”
(Reporting by Yereth Rosen; Editing by Katy Daigle and Philippa Fletcher)
Our goal is to create a safe and engaging place for users to connect over interests and passions. In order to improve our community experience, we are temporarily suspending article commenting.
World's ice is melting two-thirds faster than in the 1990s
Olivia Rudgard
Mon., January 25, 2021,
Algal bloom on Greenland - Jim McQuaid
The first ever satellite study of global ice loss found that rates have risen by 65 per cent over 23 years.
The University of Leeds study, published in the journal The Cryosphere, found that melting has accelerated within the past three decades, from 0.8 trillion tons per year in the 1990s to 1.3 trillion tons per year by 2017.
Two-thirds of the melting was caused by a warming atmosphere while the remaining third took place in the oceans.
While the 215,000 glaciers covered by the study, as well as Arctic sea ice, were primarily impacted by rising air temperatures, rising ocean temperatures caused melting in the Antarctic ice sheet. The Greenland ice sheet was affected by a mixture of both.
The melting of ice on land has pushed up global sea levels by 35mm, while the loss of sea ice means more heat is absorbed by the earth rather than being reflected away, accelerating warming in the Arctic.
Lead author Dr Thomas Slater, a research fellow at Leeds' centre for polar observation and modelling, said: "Although every region we studied lost ice, losses from the Antarctic and Greenland ice sheets have accelerated the most.
"The ice sheets are now following the worst-case climate warming scenarios set out by the Intergovernmental Panel on Climate Change. Sea-level rise on this scale will have very serious impacts on coastal communities this century."
A separate study in the journal Nature Communications, also from Leeds University, found that minerals blown onto the Greenland ice sheet fuel faster melting through darkening the surface causing more heat absorption.
Phosphorus blown onto the sheet from local rock outcrops as part of the mineral hydroxylapatite fuels the algae, which has covered a large swathe of the sheet now known as the "Dark Zone".
Co-author Jim McQuaid, of Leeds' school of earth and environment, said: "As dryland areas in northerly latitudes become even drier under climate change, we can expect to see more dust transported and deposited on the Greenland Ice Sheet, further fuelling algal blooms."
The first ever satellite study of global ice loss found that rates have risen by 65 per cent over 23 years.
The University of Leeds study, published in the journal The Cryosphere, found that melting has accelerated within the past three decades, from 0.8 trillion tons per year in the 1990s to 1.3 trillion tons per year by 2017.
Two-thirds of the melting was caused by a warming atmosphere while the remaining third took place in the oceans.
While the 215,000 glaciers covered by the study, as well as Arctic sea ice, were primarily impacted by rising air temperatures, rising ocean temperatures caused melting in the Antarctic ice sheet. The Greenland ice sheet was affected by a mixture of both.
The melting of ice on land has pushed up global sea levels by 35mm, while the loss of sea ice means more heat is absorbed by the earth rather than being reflected away, accelerating warming in the Arctic.
Lead author Dr Thomas Slater, a research fellow at Leeds' centre for polar observation and modelling, said: "Although every region we studied lost ice, losses from the Antarctic and Greenland ice sheets have accelerated the most.
"The ice sheets are now following the worst-case climate warming scenarios set out by the Intergovernmental Panel on Climate Change. Sea-level rise on this scale will have very serious impacts on coastal communities this century."
A separate study in the journal Nature Communications, also from Leeds University, found that minerals blown onto the Greenland ice sheet fuel faster melting through darkening the surface causing more heat absorption.
Phosphorus blown onto the sheet from local rock outcrops as part of the mineral hydroxylapatite fuels the algae, which has covered a large swathe of the sheet now known as the "Dark Zone".
Co-author Jim McQuaid, of Leeds' school of earth and environment, said: "As dryland areas in northerly latitudes become even drier under climate change, we can expect to see more dust transported and deposited on the Greenland Ice Sheet, further fuelling algal blooms."
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