Tuesday, July 15, 2014

Polar Vortex in July?

We have a refreshing blast of cool air coming down from the Arctic region that will make things a little more comfortable for many of us in the eastern half of the country. Even as far south and west as where I live in Texas will get some relief. It was suppose to be over 100 degrees F this week where I live (that is about normal), but will only be about 90, instead. Believe me, that is relief.

But, it comes with a cost. If cool air is moving down from the Arctic, what is taking its place?  Take a look at this figure from the Climate Reanalyzer:

Source: Climate Reanalyzer

Blue areas are where the air temperature is cooler than the long term average for this date. You can clearly see the big mass of cool air that is coming down as the polar vortex. The red areas are where the temperature is warmer than the long term average for this date. And, you can see how as the cool air moves southward, warm air is moving northward in the western U.S. and Canada to take the place of the cool air.

This illustrates the difference between weather and climate. People in the Midwest can look that the weather and wonder, 'What happened to global warming?," while the people out west will look at the weather and say, "This is global warming at work!" Neither is right.

Climate is about the long-term, not the day-to-day. The polar vortex by itself is not any indication of global warming, one way or the other. But, we can look at the mechanics involved and try to determine if there is something here that is indicative of global warming, one way or the other. Is the polar vortex caused by global warming? Would we have these kinds of events if not for the additional energy in the atmosphere? Or, is this an indication of natural cycles and the planet is just going through a natural shift?

These are the kinds of questions scientists ask and try to answer. But, I have a different question.

What does this mean about the Arctic sea ice? The sea ice is in bad shape this year already, even before the blast of warm air. Will this help to lead to a huge collapse, ala 2012? Let's hope not. Here is a graphic of the sea ice extent from the Polar Portal. White areas have 100% ice. Areas with less than that are shaded grey. The deeper the shade of grey, the less ice there is.

Source: Polar Portal

This shows the sea ice extent is already way below normal, but it also shows an extensive area with considerable melt. If all of that shaded area melts by September it would probably be the lowest minimum extent ever measured. There is a lot of melt season left, so I am not making a forecast. But, I have to think this blast of warm air into the Arctic is not a good thing.

No comments:

Post a Comment