The permafrost bomb is ticking

The permafrost bomb is ticking

SOURCE: Yale Climate Connections DATE: February 12, 2019 SNIP: About a fifth of the Northern Hemisphere landmass is permafrost, ground that has been mostly frozen for half a million years or more. Now there are signs of thaw appearing in many places across this vast landscape circling the Arctic, and at accelerated rates. It is only a matter of time until the incremental thawing of the permafrost reaches a tipping point of no return, a state of accelerated and irreversible change, the side effects of which might well push other parts of the Arctic beyond their own tipping points. Quite possibly, we are poised to witness such a transformation within our lifetimes – ice sheet loss, increased frequencies of fires in the tundra and boreal forests, and complete habitat loss for marine mammals, to name just a few examples of the changes that could occur. The major side effect of a thawing permafrost is that it will further enhance global warming with the release of large quantities of methane, a potent greenhouse gas. The permafrost contains organic matter, and thawing will enable bacterial decomposition that will release methane as a byproduct of anaerobic respiration. The last time there was a large-scale thaw of the permafrost was four interglacials ago. Evidence of this thawing event can be found in Siberian caves where stalactites and stalagmites growth last occurred at that time. Such deposits can only form when there is liquid water flowing. At the time of the thaw, about 450,000 years ago, the climate was about 1.5°C warmer than pre-industrial temperatures. Today, the temperature is nearly as warm – 1°C...
Climate change to cause more damage to Canada’s northern roads than previously feared

Climate change to cause more damage to Canada’s northern roads than previously feared

SOURCE: Global News DATE: January 17, 2019 SNIP: The impact of climate change on roads and other crucial structures in Canada’s North is likely to be even greater than feared, says new detailed research. Scientists have long warned that Canada’s northwest corner is warming more quickly than almost any other spot on the globe. Using modelling techniques so detailed they take a supercomputer to process, Pomeroy and his colleagues say they’ve looked more closely than any other researchers into how temperatures are likely to play out over the next century. They concluded that, if greenhouse gas emissions continue at their current level, temperatures in the area around Inuvik, N.W.T. will go up by six degrees on top of the three degrees they’ve already risen. They say roads in winter will be vulnerable to a phenomenon in which melted groundwater seeps to the surface, then refreezes into a thick layer of ice. Permafrost holding up buildings and roads will melt and retreat by another 25...
Arctic greening thaws permafrost, boosts runoff

Arctic greening thaws permafrost, boosts runoff

SOURCE: Los Alamos National Laboratory DATE: October 17, 2018 SNIP: A new collaborative study has investigated Arctic shrub-snow interactions to obtain a better understanding of the far north’s tundra and vast permafrost system. Incorporating extensive in situ observations, Los Alamos National Laboratory scientists tested their theories with a novel 3D computer model and confirmed that shrubs can lead to significant degradation of the permafrost layer that has remained frozen for tens of thousands of years. These interactions are driving increases in discharges of fresh water into rivers, lakes and oceans. “The Arctic is actively greening, and shrubs are flourishing across the tundra. As insulating snow accumulates atop tall shrubs, it boosts significant ground warming,” said Cathy Wilson, Los Alamos scientist on the project. “If the trend of increasing vegetation across the Arctic continues, we’re likely to see a strong increase in permafrost...
Acid is dribbling out of the melting permafrost in the Arctic

Acid is dribbling out of the melting permafrost in the Arctic

SOURCE: New Scientist ($$), Skeptical Science DATE: September 14, 2018 SNIP: Some patches of Arctic permafrost are bleeding acid as they melt. The dribble of acid is destroying rocks and releasing more carbon dioxide into the air – but it’s not clear how much. Permafrost is soil and sand that is permanently frozen. Climatologists have warned for years that Arctic permafrost is thawing due to climate change. This will transform the landscape, and release carbon that is locked away in the permafrost in the form of carbon dioxide and methane – adding to the greenhouse effect. However, most climatologists think the extra warming will be minor compared to that directly caused by our emissions. Now it seems that some regions of the Arctic might release more carbon dioxide than...
Greenhouse emissions from Siberian rivers peak as permafrost thaws

Greenhouse emissions from Siberian rivers peak as permafrost thaws

SOURCE: Umeå University DATE: September 4, 2018 SNIP: As permafrost degrades, previously frozen carbon can end up in streams and rivers where it will be processed and emitted as greenhouse gases from the water surface directly into the atmosphere. Quantifying these river greenhouse gas emissions is particularly important in Western Siberia – an area that stores vast amounts of permafrost carbon and is a home to the Arctic’s largest watershed, Ob’ River. Now researchers from Umeå University (and collaborators from SLU, Russia, France, and United Kingdom) have shown that river greenhouse gas emissions peak in the areas where Western Siberian permafrost has been actively degrading and decrease in areas where climate is colder, and permafrost has not started to thaw yet. The research team has also found out that greenhouse gas emissions from rivers exceed the amount of carbon that rivers transport to the Arctic Ocean. “This was an unexpected finding as it means that Western Siberian rivers actively process and release large part of the carbon they receive from degrading permafrost and that the magnitude of these emissions might increase as climate continues to warm” says Svetlana Serikova, doctoral student in the Department of Ecology and Environmental sciences, Umeå University, and one of the researchers in the...