Officially, it's the first day of spring today.
It was flurrying lightly when I walked to work and the temperature was about zero. According to local newspapers, this has been a colder, and snowier, than usual winter, and it will be a colder than usual spring. At this time last year, the temperatures averaged 13-15C higher. Well, I don't mind much. It's not cold enough that I have to bundle up with scarfs or hats, and it's quite nice to walk in the cold.
The severity of this year's winter was all over the news; it's colder than average in western Canada, while in eastern Canada, quite a number of the cities are on track to break their snow level records; Toronto apparently only has 20cm more to go. Thus some articles, like this and this, have been roughly along the lines of: "Colder than Average Winter. Ice Shelf Thickening. Global warming? Ha!"
(Tried to go back to hunt for the links as much as possible, because it's important to reference claims, but either the newspapers' search engine sucks or my 'search engine', and I'm not referring to Google, sucks. This happens very often. I'd read an article, and later, even on the same day, I'd go back to the site and I can't find it. Just yesterday night, I wanted to show Mike an article I read in the morning on BBC news. Oddly, the BBC search engine couldn't find it, but Google could. So apologies if I refer to a claim that's not linked.)
But writing off global warming because of an unseasonably cold winter is a premature, knee-jerk reaction. For the past two years, it was warmer than average and people were going "Oh No. Ice Shelf Melting. We Will All Drown." I'm sure people must have been complaining last year, "Only 60cm of Snow? What Kind of Canadian winter Is This?" This year, yes, it was colder than average -- in North America and parts of Asia, but apparently not so in western and northern Europe.
In Norway, "this February was the second-warmest since records began in the year 1900", and Germany's Federal Maritime and Hydrographic Agency says that "this winter will likely go down in history as the one with the least ice since 1720... The Gulf of Bothnia, the northern end of the Baltic Sea between Finland and Sweden, is normally completely icebound from late February until mid-March, but this winter there was ice only in its northernmost tip and in a few archipelago zones farther south". The Swedish weather service reported that this is their "warmest winter ever... the average temperature in Stockholm was above 2 degrees Celsius from December to February -- the highest temperatures since records were first kept in 1756". There was not enough snow so dog sled races and tours were canceled and "instead of dog sledding, tourists could go on hikes in the coastal mountains with the temporarily unemployed huskies". Ski races have been canceled, ice-breaker ships were also idle.
So. What's up?
First, looking at the temperatures one year at a time is statistically not significant. Just because a winter breaks records (whether high or low) is not enough for panic; one has to look at the past trend for decades. You know, a pretty chart, like this:
Moreover, statistics can be very confusing, even misleading. All those statements above about the record warm temperatures, and previous posts about record snow levels and cold temperatures -- they're all true. But here's another statistic: the globally averaged combined land and sea surface temperature was the eighth warmest on record for December and the fifth warmest on record for 2007. The combined global land and ocean surface temperature for January was the 31st warmest on record (since 1880), 0.32°F/0.18°C above the 20th century mean. Temperatures were colder than average across large parts of central and southern Asia. The January global land surface average was below the 20th century mean (-0.02°F/-0.01°C) for the first time since 1982.
So. Is it cold? Or not?
Wait, there's more. If the earth really is warming up, there could be more than one cause (referring to the oft-mentioned carbon emissions). This year's lower than average temperature have been attributed to La Niña; some warmer than average seasons have been attributed to her big brother.
And, totally separate from the La Niña phenomenon, we also happen to be at a solar irradiance minimum [Geophys. Res. Lett. 30(5): 1199, 2003]. In other words, there is cooling from a strong La Niña and there is also a little more cooling from being at a solar irradiance mimumum. So if this is still the 16th warmest winter on record, then we are all confused.
Were you expecting me to say, then global warming IS happening? Probably. I think it is. But there is no easy answer.
It was flurrying lightly when I walked to work and the temperature was about zero. According to local newspapers, this has been a colder, and snowier, than usual winter, and it will be a colder than usual spring. At this time last year, the temperatures averaged 13-15C higher. Well, I don't mind much. It's not cold enough that I have to bundle up with scarfs or hats, and it's quite nice to walk in the cold.
The severity of this year's winter was all over the news; it's colder than average in western Canada, while in eastern Canada, quite a number of the cities are on track to break their snow level records; Toronto apparently only has 20cm more to go. Thus some articles, like this and this, have been roughly along the lines of: "Colder than Average Winter. Ice Shelf Thickening. Global warming? Ha!"
(Tried to go back to hunt for the links as much as possible, because it's important to reference claims, but either the newspapers' search engine sucks or my 'search engine', and I'm not referring to Google, sucks. This happens very often. I'd read an article, and later, even on the same day, I'd go back to the site and I can't find it. Just yesterday night, I wanted to show Mike an article I read in the morning on BBC news. Oddly, the BBC search engine couldn't find it, but Google could. So apologies if I refer to a claim that's not linked.)
But writing off global warming because of an unseasonably cold winter is a premature, knee-jerk reaction. For the past two years, it was warmer than average and people were going "Oh No. Ice Shelf Melting. We Will All Drown." I'm sure people must have been complaining last year, "Only 60cm of Snow? What Kind of Canadian winter Is This?" This year, yes, it was colder than average -- in North America and parts of Asia, but apparently not so in western and northern Europe.
In Norway, "this February was the second-warmest since records began in the year 1900", and Germany's Federal Maritime and Hydrographic Agency says that "this winter will likely go down in history as the one with the least ice since 1720... The Gulf of Bothnia, the northern end of the Baltic Sea between Finland and Sweden, is normally completely icebound from late February until mid-March, but this winter there was ice only in its northernmost tip and in a few archipelago zones farther south". The Swedish weather service reported that this is their "warmest winter ever... the average temperature in Stockholm was above 2 degrees Celsius from December to February -- the highest temperatures since records were first kept in 1756". There was not enough snow so dog sled races and tours were canceled and "instead of dog sledding, tourists could go on hikes in the coastal mountains with the temporarily unemployed huskies". Ski races have been canceled, ice-breaker ships were also idle.
So. What's up?
First, looking at the temperatures one year at a time is statistically not significant. Just because a winter breaks records (whether high or low) is not enough for panic; one has to look at the past trend for decades. You know, a pretty chart, like this:
Moreover, statistics can be very confusing, even misleading. All those statements above about the record warm temperatures, and previous posts about record snow levels and cold temperatures -- they're all true. But here's another statistic: the globally averaged combined land and sea surface temperature was the eighth warmest on record for December and the fifth warmest on record for 2007. The combined global land and ocean surface temperature for January was the 31st warmest on record (since 1880), 0.32°F/0.18°C above the 20th century mean. Temperatures were colder than average across large parts of central and southern Asia. The January global land surface average was below the 20th century mean (-0.02°F/-0.01°C) for the first time since 1982.
So. Is it cold? Or not?
Wait, there's more. If the earth really is warming up, there could be more than one cause (referring to the oft-mentioned carbon emissions). This year's lower than average temperature have been attributed to La Niña; some warmer than average seasons have been attributed to her big brother.
And, totally separate from the La Niña phenomenon, we also happen to be at a solar irradiance minimum [Geophys. Res. Lett. 30(5): 1199, 2003]. In other words, there is cooling from a strong La Niña and there is also a little more cooling from being at a solar irradiance mimumum. So if this is still the 16th warmest winter on record, then we are all confused.
Were you expecting me to say, then global warming IS happening? Probably. I think it is. But there is no easy answer.
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