WASHINGTON: Himalayan glaciers are melting twice as speedy now as they have been ahead of the turn of the century, according to a new find out about that depended on recently declassified Cold War-era satellite tv for pc imagery.
The find out about, which appeared in Science Advances on Wednesday, is the newest indication that local weather trade is eating the Himalayan glaciers, threatening water supplies for masses of tens of millions of people downstream across South Asia.
"This is the clearest picture yet of how fast Himalayan glaciers are melting over this time interval, and why," mentioned lead writer Joshua Maurer, a doctoral candidate at Columbia University in New York.
Scientists combed 40 years of satellite tv for pc observations spanning 2,000 kilometers (1,243 miles) across India, China, Nepal and Bhutan, and located that the glaciers were dropping the an identical of a foot-and-a-half (45 centimeters) of ice every yr since 2000.
Many of the 20th-century observations got here from recently declassified US spy satellite tv for pc imagery.
The determine is double the volume of melting that came about from 1975 to 2000.
Past research has discovered identical traits, however the newest work is greater in its geographic and ancient scope.
It concluded that rising temperatures are the biggest factor.
Though temperatures range from place to place, average temperatures have been one level Celsius (1.eight levels Fahrenheit) upper between 2000 to 2016 than they have been between 1975 and 2000.
Other elements the researchers blamed have been changes in rainfall, with reductions tending to scale back ice cover, and the burning of fossil fuels which result in soot that lands on snowy glacier surfaces, absorbing daylight and hastening melting.
"It shows how endangered (the Himalayas) are if climate change continues at the same pace in the coming decades," mentioned Etienne Berthier, a glaciologist at France's Laboratory for Studies in Geophysics and Spatial Oceanography, who was once now not concerned within the find out about.
A separate find out about also published Wednesday discovered Greenland's ice sheet could have utterly melted within the subsequent millennium if greenhouse gasoline emissions continue at their present rate.
The Greenland ice sheet holds the an identical of 7 meters (yards) of sea stage.
"If we continue as usual, Greenland will melt," mentioned lead writer Andy Aschwanden, a research affiliate professor at the University of Alaska Fairbanks' Geophysical Institute.
It is the latest caution about warming on this planet's coldest areas.
"What we are doing right now in terms of emissions, in the very near future, will have a big long-term impact on the Greenland ice sheet, and by extension, if it melts, to sea level and human society," Aschwanden mentioned.
The find out about, which used information from Nasa's Operation IceBridge airborne campaign and was once published in Science Advances, is the newest to suggest a much better rate of soften than was once estimated by way of older fashions.
The model depends upon extra accurate representations of the flow of "outlet glaciers," river-like bodies of ice that connect to the ocean.
"Outlet glaciers play a key role in how ice sheets melt, but previous models lacked the data to adequately represent their complex flow patterns," NASA mentioned in a observation in regards to the find out about.
"The study found that melting outlet glaciers could account for up to 40 per cent of the ice mass lost from Greenland in the next 200 years."
As ocean waters have warmed over the past 20 years, they've melted the floating ice that once shielded the outlet glaciers.
As a end result, "the outlet glaciers flow faster, melt and get thinner, with the lowering surface of the ice sheet exposing new ice to warm air and melting as well."
In the next 200 years, the ice sheet model presentations that melting at present rate may just give a contribution 48 to 160 centimeters (19 to 63 inches) to global sea stage upward push, 80 % upper than earlier estimates.
In October, the UN's Intergovernmental Panel for Climate Change (IPCC) reported that heading off global local weather chaos would require a big transformation of society and the arena economy that is "unprecedented in scale," and warned time is operating out to avert crisis.
The find out about, which appeared in Science Advances on Wednesday, is the newest indication that local weather trade is eating the Himalayan glaciers, threatening water supplies for masses of tens of millions of people downstream across South Asia.
"This is the clearest picture yet of how fast Himalayan glaciers are melting over this time interval, and why," mentioned lead writer Joshua Maurer, a doctoral candidate at Columbia University in New York.
Scientists combed 40 years of satellite tv for pc observations spanning 2,000 kilometers (1,243 miles) across India, China, Nepal and Bhutan, and located that the glaciers were dropping the an identical of a foot-and-a-half (45 centimeters) of ice every yr since 2000.
Many of the 20th-century observations got here from recently declassified US spy satellite tv for pc imagery.
The determine is double the volume of melting that came about from 1975 to 2000.
Past research has discovered identical traits, however the newest work is greater in its geographic and ancient scope.
It concluded that rising temperatures are the biggest factor.
Though temperatures range from place to place, average temperatures have been one level Celsius (1.eight levels Fahrenheit) upper between 2000 to 2016 than they have been between 1975 and 2000.
Other elements the researchers blamed have been changes in rainfall, with reductions tending to scale back ice cover, and the burning of fossil fuels which result in soot that lands on snowy glacier surfaces, absorbing daylight and hastening melting.
"It shows how endangered (the Himalayas) are if climate change continues at the same pace in the coming decades," mentioned Etienne Berthier, a glaciologist at France's Laboratory for Studies in Geophysics and Spatial Oceanography, who was once now not concerned within the find out about.
A separate find out about also published Wednesday discovered Greenland's ice sheet could have utterly melted within the subsequent millennium if greenhouse gasoline emissions continue at their present rate.
The Greenland ice sheet holds the an identical of 7 meters (yards) of sea stage.
"If we continue as usual, Greenland will melt," mentioned lead writer Andy Aschwanden, a research affiliate professor at the University of Alaska Fairbanks' Geophysical Institute.
It is the latest caution about warming on this planet's coldest areas.
"What we are doing right now in terms of emissions, in the very near future, will have a big long-term impact on the Greenland ice sheet, and by extension, if it melts, to sea level and human society," Aschwanden mentioned.
The find out about, which used information from Nasa's Operation IceBridge airborne campaign and was once published in Science Advances, is the newest to suggest a much better rate of soften than was once estimated by way of older fashions.
The model depends upon extra accurate representations of the flow of "outlet glaciers," river-like bodies of ice that connect to the ocean.
"Outlet glaciers play a key role in how ice sheets melt, but previous models lacked the data to adequately represent their complex flow patterns," NASA mentioned in a observation in regards to the find out about.
"The study found that melting outlet glaciers could account for up to 40 per cent of the ice mass lost from Greenland in the next 200 years."
As ocean waters have warmed over the past 20 years, they've melted the floating ice that once shielded the outlet glaciers.
As a end result, "the outlet glaciers flow faster, melt and get thinner, with the lowering surface of the ice sheet exposing new ice to warm air and melting as well."
In the next 200 years, the ice sheet model presentations that melting at present rate may just give a contribution 48 to 160 centimeters (19 to 63 inches) to global sea stage upward push, 80 % upper than earlier estimates.
In October, the UN's Intergovernmental Panel for Climate Change (IPCC) reported that heading off global local weather chaos would require a big transformation of society and the arena economy that is "unprecedented in scale," and warned time is operating out to avert crisis.
Himalayan glaciers melting twice as fast: Study
![Himalayan glaciers melting twice as fast: Study]()
Reviewed by Kailash
on
June 20, 2019
Rating:
