Canadian Climate Survey: Temperature Graphs for 55 Cities and Towns Show Warming Trend Across Canada
Over the past month, the Sixth Estate Canadian Climate Survey has put online basic temperature charts showing local climate change in 55 cities and towns across Canada. The purpose of the project is to put a local face on climate change, which tends to be discussed in the global abstract. I hope this project will help Canadians see past the anti-science nonsense perpetrated in forums like the National Post and the Globe & Mail.
The Survey will continue, but I thought I should mark the posting of the first few dozen cities with a post summarizing what I’ve found so far. These cities and towns are in every province and all three territories. In 21 of 55 cities, annual average temperatures have increased at least 1˚Cbetween the period from 1961-1990 and the most recent 10 years on record (2002-2011).
In contrast to the claims of climate change denialists, who insist that warming is mainly a statistical blip caused by urban heat islands, most of these fast-warming weather stations aren’t actually near major cities. Certainly Charlottetown, Sault Ste Marie, Ottawa, and Saint John are on the list. But Canada’s largest cities — Montreal, Vancouver, and Toronto — are actually within the slowest-warming half of the stations charted so far. So the urban heat island effect doesn’t appear to be a major effect in Canada, which is exactly what we would expect given that it’s been convincingly relegated to second-place importance by mainstream climate science, too.
So far only two sites I charted have experienced over 2˚C in warming, and both are in the Arctic: Inuvik and Alert.
In contrast, zero sites so far have shown overall cooling since the 1961-1990 period. However, Regina‘s average temperature remains flat, and a few other places — Medicine Hat, Guelph, Edmonton, Montreal, and Saskatoon — also show negligible change (less than 0.3˚C of warming), and some of those places have actually cooled slightly between the 1980s and today.
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MoS
Montreal, Toronto and Vancouver are port or waterfront cities. Those who live on coasts are familiar with the moderating temperature influence that results.
For the prairies, it’s precipitation that matters more than temperature variations.
BTW, the focus on daytime high temperatures may be misplaced. As EnviroCan noted the big change is the narrowing of diurnal temperatures. Overnight low temps are staying higher than ever before which bodes ill for people needing a reprieve from daytime heatwaves.
Sixth Estate
MoS — Thanks for that.
Actually Vancouver, in particular, does show significant warming over the 20th century, as its chart shows; it’s just that there are many other places warming faster.
The precipitation averages are in a separate ZIP file. Once I’ve wandered through the 300-odd entries in the temperature file, I’m going to go back through and add precipitation data. My understanding is that in most cases temperature is a more direct and predictable consequence of climate change than precipitation numbers are, and in any case it’s the one people think about first, so that’s the one I started with.
I use Environment Canada’s daily mean temperatures data set. There is also a daily maximum set and a daily minimum set.