The headlines are enough to send a cold shiver through the bones of even the most bundled up hockey fan. “Face-Off: How Climate Change Could End Outdoor Hockey”, proclaims TIME, in a report on a new peer-reviewed paper in the journal Environmental Research Letters. Canadian newspapers, normally mild mannered, are uniformly worked up: even the National Post, often skeptical of climate science, says that “Global Warming Could Spell the End of Canada’s Outdoor Hockey Rink”. England, bastion of hockey fandom, is getting in on the excitement: According to The Guardian, “Climate Change Could Make Canada’s Traditional Ice Hockey Extinct”.
There’s only one problem: the paper, “Observed decreases in the Canadian outdoor skating season due to recent winter warming”, doesn’t say anything of the sort.
Most of the paper is pretty mundane and unobjectionable. Canadian winters have been getting warmer, and with that, the number of days when outdoor ice rinks can freeze has declined. In most regions, the positive relationship between warmer climate and good days for flooding rinks isn’t all that statistically significant; only in the southwest and the praries does it cross the 95% percent confidence threshold that scientists typically demand.
So how do the authors end up generating headlines proclaiming that the end of outdoor hockey is nigh? First, they start by narrowing their scope to “Southwest Canada” (read southern British Columbia and southwest Alberta), where temperatures happen to be relatively warm to start with, and where the historical trend in pond hockey viability appears strongest. Then they blindly extrapolate the last thirty years’ trend into the next few decades. Since the area has pretty mild weather (and hence few good outdoor hockey days) to start with, this lets them identify “a foreseeable end to outdoor staking in this region within the next few decades”. (I’m setting aside for now the convenient use of the past three decades’ trend, rather than the full sixty year sample that the authors have; there’s no justification given for that.) Then comes the final step: in talking to the media, the authors don’t bother to point out that their result was only for a small sliver of the country. “In the next 50 years, the skating season could disappear in most of the regions across Canada,” author Lawrence Mysak tells CTV. Good luck finding that claim anywhere in the actual peer reviewed paper.
Here’s a more accurate headline: Casual extrapolation of trends over an arbitrarily chosen period suggest less pond hockey in Cranbrook and more in Cole Harbor. (The authors report a small but statistically insignificant rise in cold days for Atlantic Canada.) Whether you think that’s a blessing or curse depends on whether you prefer Steve Yzerman or Sidney Crosby, but either way, it’s hardly the bombshell the media reports.
I’ve said it before, and I’ll say it again: There’s enough in the climate record to justify a really big effort to curb emissions and reduce the risk of dangerous change. Heck, it’s even obvious that outdoor hockey will suffer as climate change marches forward. But that doesn’t justify the proliferation of sloppy “scientific” predictions that only serve to hurt the credibility of the entire enterprise. Perhaps, to borrow the words of a wise Canadian transplant, this is the analyst in me speaking out intemperately when an activist would just shut up. But the world doesn’t want for loud voices who can tell people that the sky is falling. Better for scholars to stick to the facts, and leave it others to do with them what they will.