Permafrost refers to ground that remains completely frozen for at least two consecutive years. It locks up organic matter, mercury, carbon dioxide, and methane. As climate change causes rising temperatures, permafrost is thawing and releasing these gases.
- Radon is a radioactive, colorless, odorless noble gas formed by the radioactive decay of radium. It is naturally present in trace amounts in soil, rocks, and water.
- As permafrost thaws, radon trapped in the frozen ground can seep out and enter the atmosphere. Recent studies have detected increased levels of radon in the Arctic in areas where permafrost is thawing.
Recent Evidence of Increased Radon Release
- In a 2021 study, scientists measured radon levels at Igloolik, Nunavut, Canada from July to October when permafrost thawing is at its peak.
- Radon levels were 1.5 to 7 times higher compared to the rest of the year. The highest radon level was 77 Becquerel per cubic meter (Bq/m3) compared to typical background levels of 10-30 Bq/m3.
- Another 2021 study detected radon hotspots with levels of 100 Bq/m3 in Sweden’s sub-Arctic region in areas with thawing permafrost.
- Previously frozenpeat bogs are melting and releasing trapped radon. Underground ice barriers that formed a seal are also melting leading to increased emissions.
Potential Effects on Humans and Wildlife
- Radon is radioactive and long-term exposure can cause lung cancer by damaging the lining of lungs through alpha radiation. The WHO estimates radon causes 3-14% of global lung cancers.
- While current radon levels in the Arctic are below safe limits (100 Bq/m3 for homes), increasing emissions may make it unsafe for humans. Wildlife health may also suffer.
- Thawing permafrost and melting ice barriers could also free up trapped pollutants, heavy metals, and diseases that can contaminate the environment.
Key Statistics on Permafrost Thaw and Projections
| Category | Statistic |
| Global permafrost area | ~15 million sq. km |
| Permafrost area with high potential to release gases | ~4 million sq. km |
| Additional global warming expected if permafrost thaws fully | 0.13 to 1.69°C |
| Increase in Northern Hemisphere radon emissions if permafrost thaws fully | Up to 124% |
- By 2100, 35–95% of Northern Hemisphere permafrost could thaw if global warming is limited to 1.5°C. Under higher emissions scenarios almost all permafrost could thaw releasing trapped gasses.
- This radon release could significantly increase background radiation levels and health risks for Arctic wildlife and Indigenous populations unless emissions are cut rapidly.
Examples of Vulnerable Areas and Populations
- The North Slope of Alaska is vulnerable as the top 20 feet of permafrost has already warmed by 2°C since the 1980s. If emissions remain high, up to 90% of North Slope permafrost could thaw by 2100.
- Arctic coasts and islands in Russia like the New Siberian Islands are starting to erode rapidly as the ice-bonded permafrost that forms the basement for these islands thaws, threatening ecosystems and infrastructure.
- Sweden’s Kiruna underground iron ore mine, the largest in the world, is at risk of cave-ins as permafrost no longer reinforces mine tunnels. Mine operators are actively having to cool permafrost in surrounding areas.
- Reindeer herding is an important livelihood for Arctic Indigenous groups like the Sami in Sweden. Thawing permafrost leads to slushy ground and more difficult conditions for reindeer to access food locked under ice in the winter.
Key Steps Needed
- Permafrost thawing impacts need greater study especially on how climate change might exponentially increase radon and other emissions as thawing escalates.
- Global cooperation is urgently required to meet Paris Agreement climate targets and reduce fossil-fuel emissions to limit permafrost thaw. More assistance should be provided to vulnerable Arctic nations.
- Indigenous communities need to be closely involved in adaptation planning and monitoring given their reliance on intact permafrost. Suitable habitats must be conserved as migration routes for reindeer herders.
- Where possible, permafrost engineering measures should be undertaken to keep it frozen, especially around key infrastructure like pipelines, roads, and buildings.
Permafrost thawing driven by global warming is unveiling a hidden side-effect – increased emissions of radioactive radon gas in Arctic regions. While current radiation levels remain safe, unabated climate change this century may expose local ecosystems and communities to harmful radon pollution. Concerted international action is essential to reduce greenhouse gas emissions and adapt to permafrost thaw impacts that are now unavoidable due to past emissions.
