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Beiträge, die mit Permafrost getaggt sind
Happy to see another excellent news story about our recent Senate study of the the impact of climate change on transportation infrastructure. This story from the Nunatsiaq News looks specifically at the challenges faced by Nunavut. https://nunatsiaq.com/stories/article/thawing-permafrost-threatens-runways-in-the-north-senate-report/ #Nunavut #SenateofCanada #TRCM #cdnpoli #permafrost #NunatsiaqNews #climatechange
Thawing permafrost threatens runways in the North: Senate report
Thawing permafrost poses a threat to northern runways, says a new Senate report looking at how climate change is impacting critical infrastructure across the country.Nunatsiaq News
#Permafrost Thaw May Cause #Arctic River Erosion to Speed Up
October 09, 2024
"Permafrost, the thick layer of perennially frozen ground that covers much of the Arctic, slows down the migration of Arctic rivers, according to a new Caltech study. River migration is a common process in which a river's path meanders over time due to erosion of the riverbanks. This rerouting, which can also occur in #SuddenFloods, poses a threat for many communities that live along and depend on rivers. The findings also have implications for how the Arctic region will be impacted by a warming climate as permafrost thaws over time.
"The research was conducted in the Caltech laboratory of Michael Lamb, professor of geology, and is described in a paper appearing in the journal Nature on October 9.
"Led by graduate student Emily Geyman, the study focused on the #KoyukukRiver, a large tributary of the #YukonRiver that winds for hundreds of miles through interior Alaska. There was debate within the scientific community about whether the frozen soil along the riverbanks serves to fortify the banks against erosion or to promote it.
"'Large rivers like the Yukon or the Amazon can move tens to hundreds of feet per year,' Geyman says. "Arctic rivers in particular differ from temperate rivers because they need to thaw the material of their banks before they can pick that material up and move it.'
"Due to #ClimateChange, permafrost is slowly thawing over decades. But a river can experience drastic natural changes within a single year, with flow conditions changing from very cold and fast in early spring to warm and slow a few months later. Geyman and her collaborators leveraged these major changes that take place within a single season to gain a glimpse into how the rivers will behave in response to climate change decades or centuries into the future.
"In spring, the Koyukuk River swells in volume from snowmelt, flowing with fast, cold water. For more temperate rivers, a fast flow means more erosion. But in the Arctic, the temperature of the water matters—cold water is unable to thaw the frozen banks in order to migrate.
"In the new study, Geyman and her collaborators used satellite imagery of the Koyukuk over the past several years and developed a technique to decode high-resolution changes from the images. The team hypothesized that if permafrost was slowing the river's migration, they should only see migration later in the summer when the river water has warmed up. Their hypothesis matched with the satellite data, suggesting that permafrost does, in fact, slow down river migration.
"Next, the team compared sections of the river that flow through permafrost with those that do not. The Koyukuk is special because it traverses a patchwork of both permafrost and unfrozen ground. The team traveled to the Arctic to map the erosion on various bends of the river and found that sections without permafrost migrated twice as fast as analogous riverbends through permafrost terrain.
"The research is part of a larger effort to understand the dynamics of rivers and how they transport carbon, nutrients, and other materials trapped in the soil.
"'River migration has implications for local communities and infrastructure, and also for the Arctic environment,' Lamb says. 'About 1,500 gigatons of #carbon are stored in the frozen permafrost—about twice as much carbon as in the atmosphere, for comparison. There is also #mercury frozen in the soil that could be liberated into rivers as permafrost thaws. We are, ultimately, trying to understand what happens to these elements in the context of river erosion.'
"The work was a collaboration with local Alaska #Native communities, in particular from the town of #Huslia."
Read more:
https://www.caltech.edu/about/news/permafrost-thaw-may-cause-arctic-river-erosion-to-speed-up
#GlobalWarming #PermafrostMelt #MercuryPoisoning #CarbonSinks #WaterIsLife #ClimateChange #Arctic #Alaska
October 09, 2024
"Permafrost, the thick layer of perennially frozen ground that covers much of the Arctic, slows down the migration of Arctic rivers, according to a new Caltech study. River migration is a common process in which a river's path meanders over time due to erosion of the riverbanks. This rerouting, which can also occur in #SuddenFloods, poses a threat for many communities that live along and depend on rivers. The findings also have implications for how the Arctic region will be impacted by a warming climate as permafrost thaws over time.
"The research was conducted in the Caltech laboratory of Michael Lamb, professor of geology, and is described in a paper appearing in the journal Nature on October 9.
"Led by graduate student Emily Geyman, the study focused on the #KoyukukRiver, a large tributary of the #YukonRiver that winds for hundreds of miles through interior Alaska. There was debate within the scientific community about whether the frozen soil along the riverbanks serves to fortify the banks against erosion or to promote it.
"'Large rivers like the Yukon or the Amazon can move tens to hundreds of feet per year,' Geyman says. "Arctic rivers in particular differ from temperate rivers because they need to thaw the material of their banks before they can pick that material up and move it.'
"Due to #ClimateChange, permafrost is slowly thawing over decades. But a river can experience drastic natural changes within a single year, with flow conditions changing from very cold and fast in early spring to warm and slow a few months later. Geyman and her collaborators leveraged these major changes that take place within a single season to gain a glimpse into how the rivers will behave in response to climate change decades or centuries into the future.
"In spring, the Koyukuk River swells in volume from snowmelt, flowing with fast, cold water. For more temperate rivers, a fast flow means more erosion. But in the Arctic, the temperature of the water matters—cold water is unable to thaw the frozen banks in order to migrate.
"In the new study, Geyman and her collaborators used satellite imagery of the Koyukuk over the past several years and developed a technique to decode high-resolution changes from the images. The team hypothesized that if permafrost was slowing the river's migration, they should only see migration later in the summer when the river water has warmed up. Their hypothesis matched with the satellite data, suggesting that permafrost does, in fact, slow down river migration.
"Next, the team compared sections of the river that flow through permafrost with those that do not. The Koyukuk is special because it traverses a patchwork of both permafrost and unfrozen ground. The team traveled to the Arctic to map the erosion on various bends of the river and found that sections without permafrost migrated twice as fast as analogous riverbends through permafrost terrain.
"The research is part of a larger effort to understand the dynamics of rivers and how they transport carbon, nutrients, and other materials trapped in the soil.
"'River migration has implications for local communities and infrastructure, and also for the Arctic environment,' Lamb says. 'About 1,500 gigatons of #carbon are stored in the frozen permafrost—about twice as much carbon as in the atmosphere, for comparison. There is also #mercury frozen in the soil that could be liberated into rivers as permafrost thaws. We are, ultimately, trying to understand what happens to these elements in the context of river erosion.'
"The work was a collaboration with local Alaska #Native communities, in particular from the town of #Huslia."
Read more:
https://www.caltech.edu/about/news/permafrost-thaw-may-cause-arctic-river-erosion-to-speed-up
#GlobalWarming #PermafrostMelt #MercuryPoisoning #CarbonSinks #WaterIsLife #ClimateChange #Arctic #Alaska
Permafrost Thaw May Cause Arctic River Erosion to Speed Up
Caltech researchers show that widespread permafrost thaw may cause rivers in the Arctic to migrate faster.California Institute of Technology
#Greenland is getting greener. That could have huge consequences for the world
By Angela Dewan, CNN
Published February 13, 2024
"Warmer air temperatures have driven #IceLoss, which has in turn raised land temperatures. That has caused the melting of #permafrost, a frozen layer just beneath the Earth’s surface and found in much of the #Arctic, and that melt releases planet-warming #CarbonDioxide and #methane, contributing to more #GlobalWarming. #PermafrostMelt is also causing #LandInstability, which could impact infrastructure and buildings.
"'We have seen signs that the loss of ice is triggering other reactions which will result in further loss of ice and further ‘greening’ of Greenland, where shrinking ice exposes bare rock that is then colonized by tundra and eventually shrub,' one of the report’s authors, Jonathan Carrivick, said in a press release. 'At the same time, water released from the melting ice is moving sediment and silt, and that eventually forms wetlands and fenlands.'
"The loss of ice is creating what’s known as a #FeedbackLoop. Snow and ice typically reflect the sun’s energy back into space, preventing excessive heating in parts of the Earth. But as ice disappears, those areas absorb more solar energy, raising land surface temperatures, which can cause further melt and other negative impacts.
"#IceMelt also increases the amount of water in lakes, where water absorbs more heat than snow, which increases land surface temperatures.
"Greenland has been warming at twice the global mean rate since the 1970s, and the study’s authors warn that more extreme temperatures in the future are likely.
"Greenland is the world’s biggest island and is mostly covered by ice and #glaciers. Around 57,000 people live in the country, which is an autonomous country within the Kingdom of Denmark. Much of the population is #indigenous and many people there rely on natural #ecosystems for their survival.
"Michael Grimes, the report’s lead author, said that the flow of sediments and nutrients into coastal waters was particularly problematic for #IndigenousCommunities that rely on fishing, as well as for hunters on other parts of the island.
"'These changes are critical, particularly for the indigenous populations whose traditional subsistence hunting practices rely on the stability of these delicate #ecosystems,' he said.
"'Moreover, the loss of ice mass in Greenland is a substantial contributor to #GlobalSeaLevelRise, a trend that poses significant challenges both now and in the future.'"
https://www.cnn.com/2024/02/13/climate/greenland-ice-loss-vegetation-climate-intl/index.html
By Angela Dewan, CNN
Published February 13, 2024
"Warmer air temperatures have driven #IceLoss, which has in turn raised land temperatures. That has caused the melting of #permafrost, a frozen layer just beneath the Earth’s surface and found in much of the #Arctic, and that melt releases planet-warming #CarbonDioxide and #methane, contributing to more #GlobalWarming. #PermafrostMelt is also causing #LandInstability, which could impact infrastructure and buildings.
"'We have seen signs that the loss of ice is triggering other reactions which will result in further loss of ice and further ‘greening’ of Greenland, where shrinking ice exposes bare rock that is then colonized by tundra and eventually shrub,' one of the report’s authors, Jonathan Carrivick, said in a press release. 'At the same time, water released from the melting ice is moving sediment and silt, and that eventually forms wetlands and fenlands.'
"The loss of ice is creating what’s known as a #FeedbackLoop. Snow and ice typically reflect the sun’s energy back into space, preventing excessive heating in parts of the Earth. But as ice disappears, those areas absorb more solar energy, raising land surface temperatures, which can cause further melt and other negative impacts.
"#IceMelt also increases the amount of water in lakes, where water absorbs more heat than snow, which increases land surface temperatures.
"Greenland has been warming at twice the global mean rate since the 1970s, and the study’s authors warn that more extreme temperatures in the future are likely.
"Greenland is the world’s biggest island and is mostly covered by ice and #glaciers. Around 57,000 people live in the country, which is an autonomous country within the Kingdom of Denmark. Much of the population is #indigenous and many people there rely on natural #ecosystems for their survival.
"Michael Grimes, the report’s lead author, said that the flow of sediments and nutrients into coastal waters was particularly problematic for #IndigenousCommunities that rely on fishing, as well as for hunters on other parts of the island.
"'These changes are critical, particularly for the indigenous populations whose traditional subsistence hunting practices rely on the stability of these delicate #ecosystems,' he said.
"'Moreover, the loss of ice mass in Greenland is a substantial contributor to #GlobalSeaLevelRise, a trend that poses significant challenges both now and in the future.'"
https://www.cnn.com/2024/02/13/climate/greenland-ice-loss-vegetation-climate-intl/index.html