The Weather Vane is prepared by Daniel Bezte, a teacher by profession with a B. A. (Hon.) in geography, specializing in climatology, from the University of Winnipeg. Daniel has taught university-level classes in climate and weather and currently operates a computerized weather station at his home near Birds Hill Park, on 10 acres he plans to develop into a vegetable and fruit hobby farm.
Contact him with your questions and comments at [email protected]
Iknow last week I said we would continue our look at severe summer weather by examining what’s probably the most destructive weather phenomenon: the tornado. Well, we’ll get to that soon enough. Western areas of Manitoba did see a few thunderstorms last week as an unusual weather system moved due north through Saskatchewan, but the only real severe weather from these systems was some hail.
So, instead of discussing tornadoes and hail, there have been a few weather issues that came up over the last week that need to be addressed. The first issue has to do with the increase in Arctic sea ice over the last month. I have received a number of emails on this issue over the last week, ranging from simply asking for an explanation of what’s going on, to the “I told you so” message viewing this as more proof that global warming is a crock.
The amount of ice in the Arctic has increased dramatically over the last month. In fact, it did come close to climbing back to the long-term average by early April. This increase in ice was largely due to a cold snap in the western Arctic that allowed a large amount of first-year ice to grow during this period. While this increase is of interest, most Arctic ice scientists do not see this having much impact on this summer’s Arctic ice minimum.
Actually of more interest in the Arctic this winter was not the rapid late-season growth of the total ice coverage. Even though this will be what the anti-global warming camp jumps on, the other interesting news is that the Arctic winds this winter did not push out as much second-and third-year ice as usual – so we also saw an increase in second-and third-year ice this winter (fourth-year ice and older continued its decrease this winter). This will probably have a bigger impact on summer ice melt than the late-season increase in first-year ice.
With that said, it’s important to note that yearly changes in Arctic sea ice have not been that dramatic in the winter. Even though the Arctic has been having much warmer winters it is still darn cold. When the usual temperature is supposed to be around -35 C for a high and it’s a balmy -20 C, the region is way above average, but even at -20 C ice will form, and darn quick at that. That’s why in the winter, the average amount of ice in the Arctic only fluctuates between 15 million and 16 million square kilometres, while the summer ice coverage has been fluctuating between four million and eight million square km.
Since there is a much smaller change during the winter peak Arctic ice season compared to the summer, a relatively small change in ice cover will result in what appears to be a large increase overall. We will have to wait to see what happens this summer and over the next couple of years before any conclusions can be made.
MODELS AREN’T FORECASTS
This actually leads me to another point that has been on my mind over the last couple of months: the idea that climate models are really long-term forecasts. At least that’s the way they’re being treated. Take this latest growth in Arctic ice, for example. The climate models say Arctic ice should be decreasing, but wait a minute, didn’t it grow over and above what the models thought it should over the last couple of months? Well, the models are now wrong aren’t they? Since the models are now wrong, shouldn’t we also throw out everything they predicted?
Well, I don’t know about you, but from what I’ve learned over the years, models are not forecasts, never have been and were never intended to be. Why they’ve come to be treated as such is beyond me. A model is supposed to predict long-term trends in the weather, not day-to-day, month-to-month or even year-to-year weather. This type of variability is what’s known as “weather,” and these are climate models, not weather models.
Finally the last point of interest on this issue is that the global temperatures have been crunched for March and according to the U. S. National Oceanic and Atmospheric Administration (NOAA), the globe had the warmest March ever recorded, eclipsing the previous record set in 2002 by 0.03 C. NASA recorded March a little cooler than NOAA, coming in 0.01 C behind the 2002 record. Interestingly, NASA had the period of January to March as the warmest ever recorded while NOAA had that period the fourth warmest. Also, if you didn’t already guess it, Canada saw the warmest temperature anomalies during March – nowhere on Earth was it as much above average as it was here in Canada (only in Canada, eh?).
Next issue we’ll go back to our look at thunderstorms and hail.