Analysis: Rapidly thawing permafrost is acidifying streams across North America

Elliott Skierszkan is an assistant professor in the Department of Earth Sciences at Carleton University and Andras J. Szeitz is a PhD at the School of Earth, Environment & Society at McMaster University. This article was co-authored by Owen Kemp-Griffin, the Land Guardian Manager of the Natural Resources Department of the Tr’ondëk Hwëch’in First Nation.This article is republished from The Conversation under a Creative Commons license. Read the original article.

Streams are abruptly acidifying and turning orange or milky-white across vast regions of North America’s northwest. This is caused by permafrost thaw — an outcome of a warming climate that has immediate consequences for water and wildlife.

Stream acidification is driven by the weathering of naturally occurring sulphide minerals, which release acid, sulphate and toxic metals into groundwater and streams. This is known as acidic drainage. Water can become “rusty” for several kilometres downstream as iron and aluminium minerals enter streams.

Thawing permafrost means acidic groundwater can seep through the soil and react with water, oxygen and soils or bedrock containing sulphide minerals. The chemical reactions resulting from this interaction produce springs containing acid and metals.

We recently conducted a study on stream acidification with support from the Tr’ondëk Hwëch’in First Nation centred in the Tombstone Waters Observatory (TWO), a hydrological monitoring facility led by Prof. Sean Carey at McMaster University and located in central Yukon.

We found some bodies of water in the area have become highly acidic within only a few years. Such rapid shifts are rarely documented in natural watersheds and highlight how quickly permafrost thaw can alter water quality.

Rapidly changing northern environments

The emergence of acidic drainage is one example of the profound environmental changes underway across northern landscapes. Regions near the Arctic are warming more than three times faster than the global average, resulting in Arctic temperatures unseen in recent millennia.

While our research focused on Yukon, researchers have made similar observations across mountain and polar regions, including in neighbouring Alaska, the Andes, the Pyrenees and the Alps.

This suggests that accelerated sulphide weathering is a widespread consequence of glacier retreat and thawing permafrost.

The risk is driven by geology, particularly the sulphide-rich rocks that are common in North America’s northwest. An immediate consequence is deteriorating water quality that is degrading aquatic ecosystems in ways that we don’t yet fully understand.

Major rivers presently appear resilient because acid is neutralized and metals are diluted in the waterway. But the long-term outcomes for big rivers remain uncertain.

The impacts don’t end in the water. Acid produced by sulphide weathering reacts with carbonate minerals and alkalinity in a process similar to mixing vinegar and baking soda. This reaction helps neutralize acidity, but it also releases carbon dioxide into the atmosphere, potentially contributing to further permafrost thaw.

Working with local communities

Given the scale of stream acidification, and the immediate risk it poses to water security and food security, it’s essential that researchers work closely with local communities to identify research priorities.

Water-quality monitoring at the Tombstone Waters Observatory was initiated after the Tr’ondëk Hwëch’in First Nation raised concerns about water quality on their territory, particularly in Ddhäl Ch’èl Cha Nän (Tombstone Territorial Park).

This data provided us with a rare opportunity to observe the dramatic change in water chemistry in real time, and supported the observations made by community members.

For the Tr’ondëk Hwëch’in, these findings carry profound significance because a healthy watershed is critical to their cultural identity, subsistence harvesting and stewardship responsibilities.

Water is also essential for drinking and fisheries. Indigenous communities are among the first to experience deteriorating water quality, making community engagement essential for guiding research and mitigation efforts.

The climate-driven deterioration of water quality within Indigenous territories is an environmental concern as well as a challenge to community health and cultural relationships and responsibilities that have endured for generations.

Evolving management strategies

Changing water quality will have significant implications for how society handles water resource monitoring and land-use planning in the coming years and decades.

The Yukon government has intensified monitoring and provided public advisories regarding drinking water, including new guidance for Tombstone Territorial Park.

A dedicated, community-driven campaign to “Protect the Peel” watershed from development succeeded in 2011 to protect one of North America’s largest undisturbed sub-Arctic watersheds, aiming in part to prevent water quality degradation.

However, our recent observations show that this watershed is being altered by previously unanticipated consequences of a warming climate.

Deteriorating water quality also has implications for the mining sector. Mining sites treat water to remove metals and acidity before it is released.

However, unanticipated increases in river-borne metals from thawing permafrost have, in at least one case, overwhelmed local treatment capacity and required tens of millions of dollars in urgent adaptations. This should prompt mining companies and regulators to evaluate and mitigate risks of thawing permafrost on mining operations.

Stream acidification is yet another example of how climate change is driving unanticipated impacts with immediate consequences for human welfare and the environment.

Identifying landscapes vulnerable to acidifying streams will help inform conservation and land-management strategies to protect species at risk and their habitats. Watershed plans and water management policies will need to incorporate our growing understanding of how permafrost thaw is degrading water quality.

Without years of observations and continuous measurements, rapid changes in water quality could have gone undetected, or been recognized only after major ecological or human impacts had already occurred.

Our ability to adapt to a warming climate hinges on our ability to detect and understand such shifts over time. Canada must continue to invest in scientific research that supports better-informed regulatory processes.

This article was co-authored by Owen Kemp-Griffin, the Land Guardian Manager of the Natural Resources Department of the Tr’ondëk Hwëch’in First Nation.

Elliott Skierszkan is an assistant professor in the Department of Earth Sciences at Carleton University and Andras J. Szeitz is a PhD at the School of Earth, Environment & Society at McMaster University. This article is republished from The Conversation under a Creative Commons license. Read the original article.