The weather page is prepared by Daniel Bezte. Dan has a BA Honours degree in geography, specializing in climatology, from the U of W. He has taught climate and weather classes at the U of W, and is a guest climate expert on CJOB’s morning show with Larry Updike. Daniel runs a computerized weather station on his 10 acres near Birds Hill Park, which he plans to develop into a small vegetable and fruit hobby farm.
Daniel welcomes questions and comments at [email protected]
In our last issue we ended our article by looking at how the decrease in Arctic sea ice could affect our weather. I pointed out that the simple answer is “We just don’t really know.” When the climate system is disrupted on a large scale it tends to search for a new stable state. What this means is that while Arctic ice was stable, Arctic weather patterns were rather stable. As the ice melt increases, Arctic weather becomes increasingly unstable. New weather patterns emerge and these patterns influence the weather in other regions of the world. Remember, our weather is strongly controlled by what goes on in the Arctic.
A while back I wrote some articles on chaos theory. In these articles I tried to demonstrate just what is meant by chaos theory and how it fits in with weather.
Imagine a blender filled up with any fluid you want. Turn the blender on and leave it at a set power level. After a few seconds you will notice that a general stable pattern emerges in the overall flow of the fluid. This is like the Earth’s climate system. If the energy input remains relatively stable then the general pattern will remain stable. The individual particles in the fluid are our day-to-day weather. If you were able to watch these individual particles you would see that, while they follow a general pattern, they tend to move around chaotically, moving and jumping from one place in the general pattern to another.
PATTERNS FROM CHAOS
Now, let’s tie this into what’s going on in the Arctic. As I have hopefully pointed out over the last month, as the amount of Arctic ice declines the amount of energy being absorbed goes up. This is extra energy that is normally not in the system. At some point (which we may already be hitting) that extra energy will cause a shift in the general climate pattern. This would be similar to what would happen in our blender analogy. If we click on a higher power setting, the fluid in our blender would change its pattern all of a sudden. While the new pattern might be fairly similar, it would be different. Also, for a short time after the increase in power, the old pattern breaks down and the overall flow itself becomes chaotic before the new pattern emerges.
Imagine if this happens due to a decrease in Arctic sea ice. This is one of the reasons some scientists are nervous. What will happen to our climate and weather if Arctic sea ice loss does lead to a shift in the general climate pattern? And are we beginning to see signs of that shift starting?
Last article I pointed out a new pressure pattern has begun to emerge in the Arctic over the last few years. It is known as the Arctic rapid change pattern, or Arctic Dipole. The Arctic Dipole pattern features anomalous high pressure on the North American side of the Arctic, and low pressure on the Eurasian side. Before this new pattern emerged, Arctic weather was largely influenced by two different patterns, the North Atlantic Oscillation (NAO) and Arctic Oscillation (AO). Even with these two patterns the weather was still difficult to predict. Now, with a third pattern competing to influence or control the weather in this part of the world, things will likely become not just more difficult to predict, but we will likely see weather patterns that we haven’t seen before.
STRONGER ARCTIC STORMS
This new Arctic pressure pattern is not the only change we have seen in the Arctic. Research is beginning to show that storm systems in the Arctic are getting bigger and stronger. Simmonds and Keay (2009) found that September storms over the east Arctic intensified by about one millibar over the past 30 years and had grown about 50 miles larger in diameter. These larger, stronger storms mean higher winds, which tend to help break down more sea ice, which in turn leads to more energy being absorbed and released – continuing, or helping to enforce, the positive feedback loop.
Could we be wrong about why sea ice is declining in the Arctic? Could it simply be a natural cycle? Possibly, but at a sea ice conference held in 2008 none of the 88 presenters expressed the view that the current long-term decline in Arctic sea ice was completely natural, or that we could expect the decline to reverse this century. The consensus at this conference was that summertime sea ice will probably be gone by 2030.
Next week we’ll take a look at spring weather forecasts.