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Beiträge, die mit ArcticWarming getaggt sind
#Arctic #tundra is now emitting more #carbon than it absorbs, US agency says
Drastic shift driven by frequent #wildfires, pushing surface air #temperatures to second-warmest on record since 1900
by Dharna Noor, Tue 10 December
"The Arctic tundra is undergoing a dramatic transformation, driven by frequent wildfires that are turning it into a net source of carbon dioxide emissions after millennia of acting as a carbon sink, the US National Oceanic and Atmospheric Administration (#Noaa) said on Tuesday.
"This drastic shift is detailed in Noaa’s 2024 Arctic Report Card, which revealed that annual surface air temperatures in the Arctic this year were the second-warmest on record since 1900.
“'Our observations now show that the Arctic tundra, which is experiencing warming and increased wildfire, is now emitting more carbon than it stores, which will worsen climate change impacts,' said Rick Spinrad, a Noaa administrator.
"The report, led by scientists from the Woodwell Climate Research Center in Falmouth, Massachusetts, found that the Arctic is warming faster than the global average for the 11th year in a row.
"Currently, it is warming at up to four times the global rate, the authors found.
"Climate warming has dual effects on the Arctic. While it stimulates plant productivity and growth, which remove carbon dioxide from the atmosphere, it also leads to increased surface air temperatures that cause permafrost to thaw.
"When permafrost thaws, carbon trapped in the frozen soil is decomposed by microbes and released into the atmosphere as carbon dioxide and methane, two potent greenhouse gases.
"'We need accurate, holistic and comprehensive knowledge of how climate changes will affect the amount of carbon the Arctic is taking up and storing, and how much it’s releasing back into the atmosphere, in order to effectively address this crisis,' said Dr Sue Natali, a scientist at the Woodwell Center who contributed to the research. 'This report represents a critical step toward quantifying these emissions at scale.'
"Human-caused climate change is also intensifying high-latitude wildfires, which have increased in burned area, intensity and associated carbon emissions.
"Wildfires not only combust vegetation and soil organic matter, releasing carbon into the atmosphere, but they also strip away insulating soil layers, accelerating long-term permafrost thaw and its associated carbon emissions.
"'In recent years, we’ve seen how increasing fire activity from climate change threatens both communities and the carbon stored in permafrost, but now we’re beginning to be able to measure the cumulative impact to the atmosphere, and it’s significant,' said Dr Brendan Rogers, Woodwell Climate scientist and report contributor."
https://www.theguardian.com/world/2024/dec/10/arctic-tundra-carbon-shift?utm_source=firefox-newtab-en-us
#GlobalWarming #GlobalBurning #2024ArcticReportCard #ArcticWarming #Tundra #PermafrostThaw #GreenhouseGases #Methane #Microbes #ClimateCrisis #ClimateChange
Drastic shift driven by frequent #wildfires, pushing surface air #temperatures to second-warmest on record since 1900
by Dharna Noor, Tue 10 December
"The Arctic tundra is undergoing a dramatic transformation, driven by frequent wildfires that are turning it into a net source of carbon dioxide emissions after millennia of acting as a carbon sink, the US National Oceanic and Atmospheric Administration (#Noaa) said on Tuesday.
"This drastic shift is detailed in Noaa’s 2024 Arctic Report Card, which revealed that annual surface air temperatures in the Arctic this year were the second-warmest on record since 1900.
“'Our observations now show that the Arctic tundra, which is experiencing warming and increased wildfire, is now emitting more carbon than it stores, which will worsen climate change impacts,' said Rick Spinrad, a Noaa administrator.
"The report, led by scientists from the Woodwell Climate Research Center in Falmouth, Massachusetts, found that the Arctic is warming faster than the global average for the 11th year in a row.
"Currently, it is warming at up to four times the global rate, the authors found.
"Climate warming has dual effects on the Arctic. While it stimulates plant productivity and growth, which remove carbon dioxide from the atmosphere, it also leads to increased surface air temperatures that cause permafrost to thaw.
"When permafrost thaws, carbon trapped in the frozen soil is decomposed by microbes and released into the atmosphere as carbon dioxide and methane, two potent greenhouse gases.
"'We need accurate, holistic and comprehensive knowledge of how climate changes will affect the amount of carbon the Arctic is taking up and storing, and how much it’s releasing back into the atmosphere, in order to effectively address this crisis,' said Dr Sue Natali, a scientist at the Woodwell Center who contributed to the research. 'This report represents a critical step toward quantifying these emissions at scale.'
"Human-caused climate change is also intensifying high-latitude wildfires, which have increased in burned area, intensity and associated carbon emissions.
"Wildfires not only combust vegetation and soil organic matter, releasing carbon into the atmosphere, but they also strip away insulating soil layers, accelerating long-term permafrost thaw and its associated carbon emissions.
"'In recent years, we’ve seen how increasing fire activity from climate change threatens both communities and the carbon stored in permafrost, but now we’re beginning to be able to measure the cumulative impact to the atmosphere, and it’s significant,' said Dr Brendan Rogers, Woodwell Climate scientist and report contributor."
https://www.theguardian.com/world/2024/dec/10/arctic-tundra-carbon-shift?utm_source=firefox-newtab-en-us
#GlobalWarming #GlobalBurning #2024ArcticReportCard #ArcticWarming #Tundra #PermafrostThaw #GreenhouseGases #Methane #Microbes #ClimateCrisis #ClimateChange
The role of #RossbyWaves in polar #weather and #climate
by Tim Woollings, et al.
13 Jan 2023
Abstract:
"Recent Arctic warming has fuelled interest in the weather and climate of the polar regions and how this interacts with lower latitudes. Several interesting theories of polar-midlatitude linkages involve Rossby wave propagation as a key process even though the meridional gradient in planetary vorticity, crucial for these waves, is weak at high latitudes. Here we review some basic theory and suggest that Rossby waves can indeed explain some features of polar variability, especially when relative vorticity gradients are present.
"We suggest that large-scale polar flow can be conceptualised as a mix of geostrophic turbulence and Rossby wave propagation, as in the midlatitudes, but with the balance tipped further in favour of turbulent flow. Hence, isolated vortices often dominate but some wavelike features remain. As an example, quasi-stationary or weakly westward-propagating subpolar anomalies emerge from statistical analysis of observed data, and these are consistent with some role for wave propagation. The noted persistence of polar cyclones and anticyclones is attributed in part to the weakened effects of wave dispersion, the mechanism responsible for the decay of midlatitude anomalies in downstream development. We also suggest that the vortex-dominated nature of polar dynamics encourages the emergence of annular mode structures in principal component analyses of extratropical circulation.
"Finally, we consider how Rossby waves may be triggered from high latitudes. The linear mechanisms known to balance localised heating at lower latitudes are shown to be less efficient in the polar regions. Instead, we suggest the direct response to sea ice loss often manifests as a heat low, with radiative cooling balancing the heating. If the relative vorticity gradient is favourable this does have the potential to trigger a Rossby wave response, although this will often be weak compared to waves forced from lower latitudes."
Read more:
https://wcd.copernicus.org/articles/4/61/2023/
#Copernicus #Weather #ClimateChange #ArcticMelt #ArcticWarming #GlobalWarming #GlobalHotSpots
by Tim Woollings, et al.
13 Jan 2023
Abstract:
"Recent Arctic warming has fuelled interest in the weather and climate of the polar regions and how this interacts with lower latitudes. Several interesting theories of polar-midlatitude linkages involve Rossby wave propagation as a key process even though the meridional gradient in planetary vorticity, crucial for these waves, is weak at high latitudes. Here we review some basic theory and suggest that Rossby waves can indeed explain some features of polar variability, especially when relative vorticity gradients are present.
"We suggest that large-scale polar flow can be conceptualised as a mix of geostrophic turbulence and Rossby wave propagation, as in the midlatitudes, but with the balance tipped further in favour of turbulent flow. Hence, isolated vortices often dominate but some wavelike features remain. As an example, quasi-stationary or weakly westward-propagating subpolar anomalies emerge from statistical analysis of observed data, and these are consistent with some role for wave propagation. The noted persistence of polar cyclones and anticyclones is attributed in part to the weakened effects of wave dispersion, the mechanism responsible for the decay of midlatitude anomalies in downstream development. We also suggest that the vortex-dominated nature of polar dynamics encourages the emergence of annular mode structures in principal component analyses of extratropical circulation.
"Finally, we consider how Rossby waves may be triggered from high latitudes. The linear mechanisms known to balance localised heating at lower latitudes are shown to be less efficient in the polar regions. Instead, we suggest the direct response to sea ice loss often manifests as a heat low, with radiative cooling balancing the heating. If the relative vorticity gradient is favourable this does have the potential to trigger a Rossby wave response, although this will often be weak compared to waves forced from lower latitudes."
Read more:
https://wcd.copernicus.org/articles/4/61/2023/
#Copernicus #Weather #ClimateChange #ArcticMelt #ArcticWarming #GlobalWarming #GlobalHotSpots
The role of Rossby waves in polar weather and climate
Abstract. Recent Arctic warming has fuelled interest in the weather and climate of the polar regions and how this interacts with lower latitudes.wcd.copernicus.org