New York City recently grappled with one of its worst air quality experiences in half a century, a victim of dense smoke wafting southwards from the Quebec province in Canada. The headlines were swift to pin the blame on climate change. Yet, Clifford Mass, a professor of atmospheric sciences at the University of Washington, writing in the Wall Street Journal, begs to differ. In his words,
“these claims are inconsistent with peer-reviewed science, the observational record and our growing understanding of the meteorology associated with wildfire events.”
Professor Mass, who has published extensively on wildfire meteorology and studied the effects of climate change on atmospheric circulation, as well as receiving funding from both the US Forest Service and the National Science foundation to specifically research wildfire meteorology, offers a different perspective. He explains that an
“unusual atmospheric circulation resulted in wildfire ignition and rapid growth,” with climate change being “only a minor player in this event.”
The crux of his argument is rooted in the understanding of the natural ecology and the associated climatic events of the boreal forests of northern Quebec. Fire isn’t a stranger in these woods. The region’s ecosystem relies on fires for the release of seeds and overall forest health. Fires are not unusual during a narrow window from mid-April to early June, after winter snow has melted and before grasses and other smaller plants grow, reducing flammability.
Historically, the boreal fires have been known to occur during the spring, like the infamous May 2010 fire and the May 1870 Saguenay fire. According to Mass,
“large boreal forest fires during the spring in Canada are neither unusual nor a sign of climate change.”
The recent wildfires began on June 2, ignited by hundreds of lightning strikes on vegetation dried by a week of unusually warm weather. The Canadian drought monitor reflected normal moisture conditions and temperatures close to or below average prior to the warm spell. This refutes any claims of abnormal dryness as the ignition point.
The circumstances were set in motion when a high-pressure system started forming over south-central Canada around May 27. It led to an environment ripe for wildfires, warming and drying the area for several days into early June. The final ignition source arrived early in June with a lightning storm associated with low pressure. As Mass aptly puts it,
“It was the perfect storm for smoke in New York, with several independent elements occurring in exactly the right sequence.”
However, the debate around climate change’s involvement is still rife. Mass argues,
“It’s difficult to find any plausible evidence for a significant climate-change connection to the recent New York smoke event.”
Interestingly, despite an increase in both precipitation and temperature in Quebec over the past half-century, the number of wildfires is decreasing. Mass states,
“Even assuming that this warming is entirely human-induced, it represents only a small proportion of the excessive heat during the event.”
The weather conditions in Quebec preceding the wildfire event were largely normal, and the high pressure over southern Canada, responsible for the warming, has no proven association with climate change.
Drawing a metaphor with card games, Mass underscores that our atmosphere, a chaotic system, is dominated by random natural variability. Much like the rare luck of being dealt a full house or a straight flush in a card game, many extreme weather events hinge on random factors, with climate change’s effects relatively small compared to the random variations inherent in our complex atmospheric system.