Large Rivers in Arctic Canada, Alaska Are Changing Migration Paths As Global Warming Continues

Dr. Alessandro Ielpi, an Assistant Professor in the Irving K. Barber Faculty of Science at UBC Okanagan, is a landscape scientist who is the lead author of a paper published this week in Nature Climate Change.

The study, led by Dr. Mathieu Lapôtre of Stanford University, Dr. Alvise Finotello of the University of Padua in Italy, and Dr. Pascale Roy-Léveillée of Université Laval, looks at how atmospheric warming affects Arctic rivers flowing through permafrost terrain.

Arctic River Channels Changing Due To Climate Change

(Photo : JONATHAN NACKSTRAND/AFP via Getty Images)

"The western Arctic is one of the areas in the world experiencing the greatest atmospheric warming as a result of climate change," says Dr. Ielpi.

Many northern scientists predicted that atmospheric warming would destabilize the rivers.

The understanding was that as permafrost thaws, riverbanks deteriorate, making northern rivers less stable and expected to shift channel positions more quickly.

For decades, the scientific community has been dominated by the assumption of faster channel migration due to climate change.

However, he adds, the assumption had never been validated against field observations.

Monitoring riverbank erosion and channel migration around the world, according to Dr. Ielpi, is an important tool that should be widely used to understand climate change.

A dataset of rivers found in non-permafrost regions and representative of warmer climates in the Americas, Africa, and Oceania was also analyzed as part of this study. Unlike those in the Arctic, these rivers migrated at rates consistent with previous studies.

"We tested the hypothesis that large sinuous rivers in permafrost terrain move faster as the climate warms, and we found the exact opposite," Lelpi says.

Permafrost is thawing, but the influence of other environmental changes, such as Arctic greening, mitigates its effects.

The Arctic is greening up as temperatures rise and moisture levels rise. Shrubs are spreading, becoming thicker and taller in previously sparsely vegetated areas.

Also Read: Climate Change: Antarctica and Arctic Simultaneously Experiencing More than 30 to 40 Degrees Celsius Increase in Temperature

Human-Made Fires Pollute Air with Ozone Half a World Away

Ozone is released into the atmosphere whenever fires burn once-living organic material, such as wood or fossil fuels.

According to Daniel Anderson, a graduate student in atmospheric and ocean sciences at the University of Maryland in College Park, fires contribute up to 10% of the ozone in the lower atmosphere globally.

Fire's impact is amplified in the tropics, he says, because weather patterns make it difficult for smoke produced in the tropics to escape its roughly 15°N and 15°S latitude bounds.

According to Anderson, atmospheric scientists have known that fires produce ozone since the early 1990s and have been aware of unusually high ozone levels over the sparsely populated, mostly nonindustrial western Pacific region.

Researchers have mostly attributed the ozone abundance in the lower atmosphere of the Pacific region to a natural process of upper atmosphere ozone falling to lower altitudes.

Prior studies that attempted to link pollution to fires discovered only partial evidence of the link.

Anderson and his colleagues collected air samples in renovated Gulfstream 5 jets in January and February of 2014 to trace the origins of western Pacific ozone.

These planes had scientific instruments that sucked air in from outside the plane instead of seats.

The samples could be analyzed immediately or stored in sealed cans for later analysis by the scientists.

Their investigation discovered a mixture of chemicals in their samples that could have been produced by fires or fossil fuel burning, but the presence of two telltale compounds-hydrogen cyanide and acetonitrile, which is almost exclusively produced by fires-indicated that the pollution was caused by fires.

Related article: Climate Crisis: Ground Temperatures Reaches 118 Degrees in the Arctic Circle