Tuesday, February 4, 2020
Red alert as Arctic lands grow greener
January 31, 2020
University of Edinburgh
New research techniques are being adopted by scientists tackling the most visible impact of climate change -- the so-called greening of Arctic regions. The latest drone and satellite technology is helping an international team of researchers better understand how the vast, treeless regions called the tundra is becoming greener.
https://www.sciencedaily.com/releases/2020/01/200131135140.htm?utm
New research techniques are being adopted by scientists tackling the most visible impact of climate change -- the so-called greening of Arctic regions.
The latest drone and satellite technology is helping an international team of researchers to better understand how the vast, treeless regions called the tundra is becoming greener.
As Arctic summer temperatures warm, plants are responding. Snow is melting earlier and plants are coming into leaf sooner in spring. Tundra vegetation is spreading into new areas and where plants were already growing, they are now growing taller.
Understanding how data captured from the air compare with observations made on the ground will help to build the clearest picture yet of how the northern regions of Europe, Asia and North America are changing as the temperature rises.
Now a team of 40 scientists from 36 institutions, led by two National Geographic Explorers, have revealed that the causes of this greening process are more complex -- and variable -- than was previously thought.
Researchers from Europe and North America are finding that the Arctic greening observed from space is caused by more than just the responses of tundra plants to warming on the ground. Satellites are also capturing other changes including differences in the timing of snowmelt and the wetness of landscapes.
Lead author Dr Isla Myers-Smith, of the University of Edinburgh's School of GeoSciences, said: "New technologies including sensors on drones, planes and satellites, are enabling scientists to track emerging patterns of greening found within satellite pixels that cover the size of football fields."
Professor Scott Goetz of the School of Informatics, Computing and Cyber Systems at Northern Arizona University, says this research is vital for our understanding of global climate change. Tundra plants act as a barrier between the warming atmosphere and huge stocks of carbon stored in frozen ground.
Changes in vegetation alter the balance between the amount of carbon captured and its release into the atmosphere. Small variations could significantly impact efforts to keep warming below 1.5 degrees centigrade -- a key target of the Paris Agreement. The study will help scientists to figure out which factors will speed up or slow down warming.
Co-lead author Dr Jeffrey Kerby, who was a Neukom Fellow at Dartmouth College while conducting the research, said: "Besides collecting new imagery, advances in how we process and analyse these data -- even imagery that is decades old -- are revolutionising how we understand the past, present, and future of the Arctic."
Alex Moen, Vice President of Explorer Programs at the National Geographic Society, said: "We look forward to the impact that this work will have on our collective understanding of the Arctic for generations to come."
The paper, published in Nature Climate Change, was funded in part by the National Geographic Society and government agencies in the UK, North America and Europe, including NASA's Arctic Boreal Vulnerability Experiment (ABoVE) and the UK's Natural Environment Research Council.
The research was also supported by the Synthesis Centre of the German Centre for Integrative Biodiversity Research, and was informed by a U.S. National Academy of Sciences workshop, Understanding Northern Latitude Vegetation Greening and Browning.
Story Source:
Materials provided by University of Edinburgh. Note: Content may be edited for style and length.
Journal Reference:
Isla H. Myers-Smith, Jeffrey T. Kerby, Gareth K. Phoenix, Jarle W. Bjerke, Howard E. Epstein, Jakob J. Assmann, Christian John, Laia Andreu-Hayles, Sandra Angers-Blondin, Pieter S. A. Beck, Logan T. Berner, Uma S. Bhatt, Anne D. Bjorkman, Daan Blok, Anders Bryn, Casper T. Christiansen, J. Hans C. Cornelissen, Andrew M. Cunliffe, Sarah C. Elmendorf, Bruce C. Forbes, Scott J. Goetz, Robert D. Hollister, Rogier de Jong, Michael M. Loranty, Marc Macias-Fauria, Kadmiel Maseyk, Signe Normand, Johan Olofsson, Thomas C. Parker, Frans-Jan W. Parmentier, Eric Post, Gabriela Schaepman-Strub, Frode Stordal, Patrick F. Sullivan, Haydn J. D. Thomas, Hans Tømmervik, Rachael Treharne, Craig E. Tweedie, Donald A. Walker, Martin Wilmking, Sonja Wipf. Complexity revealed in the greening of the Arctic. Nature Climate Change, 2020; 10 (2): 106 DOI: 10.1038/s41558-019-0688-1
Scientists find record warm water in Antarctica, pointing to cause behind troubling glacier melt
January 29, 2020
New York University
Scientists have observed the presence of warm water at a vital point underneath a glacier in Antarctica -- an alarming discovery that raises concerns about sea-level rise around the globe.
https://www.sciencedaily.com/releases/2020/01/200131135140.htm?utm
A team of scientists has observed, for the first time, the presence of warm water at a vital point underneath a glacier in Antarctica -- an alarming discovery that points to the cause behind the gradual melting of this ice shelf while also raising concerns about sea-level rise around the globe.
"Warm waters in this part of the world, as remote as they may seem, should serve as a warning to all of us about the potential dire changes to the planet brought about by climate change," explains David Holland, director of New York University's Environmental Fluid Dynamics Laboratory and NYU Abu Dhabi's Center for Global Sea Level Change, which conducted the research. "If these waters are causing glacier melt in Antarctica, resulting changes in sea level would be felt in more inhabited parts of the world."
The recorded warm waters -- more than two degrees above freezing -- flow beneath the Thwaites Glacier, which is part of the Western Antarctic Ice Sheet. The discovery was made at the glacier's grounding zone -- the place at which the ice transitions between resting fully on bedrock and floating on the ocean as an ice shelf and which is key to the overall rate of retreat of a glacier.
Thwaites' demise alone could have significant impact globally.
It would drain a mass of water that is roughly the size of Great Britain or the state of Florida and currently accounts for approximately 4 percent of global sea-level rise. Some scientists see Thwaites as the most vulnerable and most significant glacier in the world in terms of future global sea-level rise -- its collapse would raise global sea levels by nearly one meter, perhaps overwhelming existing populated areas.
While the glacier's recession has been observed over the past decade, the causes behind this change had previously not been determined.
"The fact that such warm water was just now recorded by our team along a section of Thwaites grounding zone where we have known the glacier is melting suggests that it may be undergoing an unstoppable retreat that has huge implications for global sea level rise," notes Holland, a professor at NYU's Courant Institute of Mathematical Sciences.
The scientists' measurements were made in early January, after the research team created a 600-meter deep and 35-centimeter wide access hole and deployed an ocean-sensing device to measure the waters moving below the glacier's surface. This device gauges the turbulence of the water as well as other properties such as temperature. The result of turbulence is the mixing of fresh meltwater from the glacier and salty water from the ocean.
It marks the first time that ocean activity beneath the Thwaites Glacier has been accessed through a bore hole and that a scientific instrument measuring underlying ocean turbulence and mixing has been deployed. The hole was opened on January 8 and 9 and the waters beneath the glacier measured January 10 and 11.
Aurora Basinski, an NYU graduate student who made the turbulence measurement, said, "From our observations into the ocean cavity at the grounding zone we observed not only the presence of warm water, but also its turbulence level and thus its efficiency to melt the ice shelf base."
Another researcher, Keith Nicholls, a scientist with the British Antarctic Survey, added, "This is an important result as this is the first time turbulent dissipation measurements have been made in the critical grounding zone of the West Antarctic Ice Sheet."
This research was supported by a $2.1 million, five-year grant from the National Science Foundation (PLR-1739003). The grant is part of the International Thwaites Glacier Collaboration (ITGC), headed by the United Kingdom's Natural Environment Research Council and the National Science Foundation, which has been deploying scientists to gather the data needed to understand whether the glacier's collapse could begin in the next few decades or centuries. Other members of the field team included researchers from Penn State, Georgia Tech, and the British Antarctic Survey.
For more about the project, please visit: https://thwaitesglacier.org/projects/melt
Story Source:
Materials provided by New York University. Note: Content may be edited for style and length.
New York University
Scientists have observed the presence of warm water at a vital point underneath a glacier in Antarctica -- an alarming discovery that raises concerns about sea-level rise around the globe.
https://www.sciencedaily.com/releases/2020/01/200131135140.htm?utm
A team of scientists has observed, for the first time, the presence of warm water at a vital point underneath a glacier in Antarctica -- an alarming discovery that points to the cause behind the gradual melting of this ice shelf while also raising concerns about sea-level rise around the globe.
"Warm waters in this part of the world, as remote as they may seem, should serve as a warning to all of us about the potential dire changes to the planet brought about by climate change," explains David Holland, director of New York University's Environmental Fluid Dynamics Laboratory and NYU Abu Dhabi's Center for Global Sea Level Change, which conducted the research. "If these waters are causing glacier melt in Antarctica, resulting changes in sea level would be felt in more inhabited parts of the world."
The recorded warm waters -- more than two degrees above freezing -- flow beneath the Thwaites Glacier, which is part of the Western Antarctic Ice Sheet. The discovery was made at the glacier's grounding zone -- the place at which the ice transitions between resting fully on bedrock and floating on the ocean as an ice shelf and which is key to the overall rate of retreat of a glacier.
Thwaites' demise alone could have significant impact globally.
It would drain a mass of water that is roughly the size of Great Britain or the state of Florida and currently accounts for approximately 4 percent of global sea-level rise. Some scientists see Thwaites as the most vulnerable and most significant glacier in the world in terms of future global sea-level rise -- its collapse would raise global sea levels by nearly one meter, perhaps overwhelming existing populated areas.
While the glacier's recession has been observed over the past decade, the causes behind this change had previously not been determined.
"The fact that such warm water was just now recorded by our team along a section of Thwaites grounding zone where we have known the glacier is melting suggests that it may be undergoing an unstoppable retreat that has huge implications for global sea level rise," notes Holland, a professor at NYU's Courant Institute of Mathematical Sciences.
The scientists' measurements were made in early January, after the research team created a 600-meter deep and 35-centimeter wide access hole and deployed an ocean-sensing device to measure the waters moving below the glacier's surface. This device gauges the turbulence of the water as well as other properties such as temperature. The result of turbulence is the mixing of fresh meltwater from the glacier and salty water from the ocean.
It marks the first time that ocean activity beneath the Thwaites Glacier has been accessed through a bore hole and that a scientific instrument measuring underlying ocean turbulence and mixing has been deployed. The hole was opened on January 8 and 9 and the waters beneath the glacier measured January 10 and 11.
Aurora Basinski, an NYU graduate student who made the turbulence measurement, said, "From our observations into the ocean cavity at the grounding zone we observed not only the presence of warm water, but also its turbulence level and thus its efficiency to melt the ice shelf base."
Another researcher, Keith Nicholls, a scientist with the British Antarctic Survey, added, "This is an important result as this is the first time turbulent dissipation measurements have been made in the critical grounding zone of the West Antarctic Ice Sheet."
This research was supported by a $2.1 million, five-year grant from the National Science Foundation (PLR-1739003). The grant is part of the International Thwaites Glacier Collaboration (ITGC), headed by the United Kingdom's Natural Environment Research Council and the National Science Foundation, which has been deploying scientists to gather the data needed to understand whether the glacier's collapse could begin in the next few decades or centuries. Other members of the field team included researchers from Penn State, Georgia Tech, and the British Antarctic Survey.
For more about the project, please visit: https://thwaitesglacier.org/projects/melt
Story Source:
Materials provided by New York University. Note: Content may be edited for style and length.
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