The Invisible Reach of Climate Change
Most Canadians are aware of the costs of climate change, both the near-term effects that we already see, as well as the dramatic long-term changes yet to come. Few have thought about an unseen threat that is rising, from below the earth.
The vast frozen expanse of northern Canada has kept its underground secrets for millennia. Untold scientific and economic treasures have been locked away in a deep freeze — everything from ancient plant and animal life to rich troves of natural resources. Far below the surface are dangers, as well, separated from the atmosphere by permafrost.
Radon is one of these hazards. As a colorless, odorless gas, radon is hard to notice, but its health impact on a community can be devastating. As its name suggests, it is radioactive, and has been linked in studies to higher rates of cancer mortality.
Climate change is bringing this threat closer to the surface. Across the Arctic and sub-Arctic, permafrost is thawing. In areas where radon has been trapped below, the gas is seeping upward, silently endangering people and communities living on the land.
Paul Glover, a petrophysicist at the University of Leeds in England, has been studying the magnitude of this risk. In a report carried by the U.S. Public Broadcasting System (PBS), he contends that a 40 percent thaw in northern permafrost would cause a radon release that could raise levels of radioactivity to 200 becquerels per meter cubed (Bq/m3), which is often considered the upper limit for safe exposure.
But like many carcinogenic risks, exposure is cumulative; the risk builds over time. In fact, the World Health Organization estimates that for every 100 Bq/m3 that a person is exposed to over many years, the risk of lung cancer increases by 16 percent.
According to PBS: “Some 3.3 million people live on permafrost that will have completely melted away by 2050, according to estimates in a 2021 study. Not all of these people live in areas prone to radon but many do: For example, in parts of Canada, Alaska, Greenland and Russia. And the link between radon exposure and lung cancer is well-established, as is the fact that smoking further increases one’s risk.”
This latter point is particularly relevant to many of the communities of northern Canada, where the rate of smoking is high. In fact, a 2012 study indicated that nearly two-thirds of Inuit adults living in these areas smoke regularly, compared with 16 percent of Canadians nationwide.
PBS adds: “The type of building matters. Glover’s model found that homes built on piles or stilts, and thus separated from the ground, did not experience a boost in radon levels. Fortunately, many homes in the Arctic and sub-Arctic are constructed in this fashion. But for those that aren’t, the cost of mitigating radon could be prohibitive for low-income communities in these regions.”
Of course, steps to mitigate the risk, such as sub-slab depressurization, require as a necessary precondition an awareness of the risk; and radon can only be detected by scientific instruments. Like climate change itself, awareness often happens only after great damage has already been done.
