Image: Environment Canada
Warm & Dry
The preliminary numbers are out for the winter of 2009-2010 in Canada, and it turns out that it was the warmest and driest winter since records began in 1948. "The national average temperature for the winter 2009/2010 was 4.0°C (7.2 °F) above normal [...] The previous record was 2005/2006 which was 3.9°C above normal. At 3.2°C below normal, the winter of 1971/1972 remains the coolest." Precipitations were also significantly below normal (by 22% nationally). "The previous driest winter was 1977/1978, 20.1% below normal."
The preliminary numbers are out for the winter of 2009-2010 in Canada, and it turns out that it was the warmest and driest winter since records began in 1948. "The national average temperature for the winter 2009/2010 was 4.0°C (7.2 °F) above normal [...] The previous record was 2005/2006 which was 3.9°C above normal. At 3.2°C below normal, the winter of 1971/1972 remains the coolest." Precipitations were also significantly below normal (by 22% nationally). "The previous driest winter was 1977/1978, 20.1% below normal."
Image: Environment Canada
What This Means, and What This Doesn't Mean
Of course, this is a different thing from global warming. The "global" part is important; if we want to determine if our planet is getting warmer on average, we have to look at temperatures everywhere and not just in one country.
Of course, this is a different thing from global warming. The "global" part is important; if we want to determine if our planet is getting warmer on average, we have to look at temperatures everywhere and not just in one country.
But this certainly a sign that something is happening, and once we've combined data for all countries and oceans, we'll be able to know how the winter of 2009-2010 stacks up historically.
What About All that Snow in the US?
One thing that a lot of people are probably thinking is: But what about the US? Didn't we have a really cold winter?
One thing that a lot of people are probably thinking is: But what about the US? Didn't we have a really cold winter?
I haven't seen the numbers for the US yet, but there are a few things to consider. First, it's possible for a winter to have terrible cold snaps yet be pretty warm on average. We've had some really cold days in Canada this winter, and they are more memorable than slightly above average days, but what matters is the average for the whole winter over the whole country (and over the whole planet).
As for getting lots of snow, it's not necessarily a sign of a cold winter. Warmer air can hold more moisture, which can lead to more precipitations. So record snowfalls don't necessarily equal to record cold weather. But climate systems are very complex, with lots of variables and feedback loops, so it's hard to know exactly what caused those record snowfalls in the US (possibly warmer ocean surfaces leading to more evaporation).