by Joel Gunn
I have sympathy for the high profile scientists who are struggling with the politics of global warming: Did this or that weather event occur because of global warming? See for example this New York Times post (and the several updates) in which climate scientists address the effects of global warming on the winter Olympics. However, if you believe in thermodynamics and the interlinking of the atmosphere-ocean circulation and life processes, and that the world is warming, there is only one conclusion you can come to. Everything that is happening is to a greater or lesser degree a product of global warming. There is a legitimate question as to what degree the causes of individual events are apportioned to that trend and what part is attributable to chaotic forces. The tendency is, perhaps wisely, for scientists to hide behind chaotic forces when the politics gets too hot. However, the only real question is how the events and trend fit together, and that is admittedly complicated. But, since we have not lived with this particular change before, observation and model building have to take the lead. You can see the scientists struggling with these questions in the later parts of the blog, and we as citizens of the globe should also participate in thinking this through.
A good example is our current discussion of the wandering fragments of polar vortex and the effects they have had on our weather. When I first started seeing weather reports about the polar vortex I said, how can this be? Probably the first really interesting article I read on the behavior of the atmosphere was in the ’70s by Angell and Korshover, people with a government agency who were measuring the atmosphere in many very interesting ways. Their article was about the behavior of the polar vortex. In fact, they were discussing the reason for the cold weather in the mid ’70s. Who recalls that in the winter of ’76-’77 it was so cold the Ohio River froze over? I was sure that the Ice Ages were coming back.
Our present day relationship to the polar vortex has crept out less directly but more interestingly. After the initial reports appeared, the pieces of the global weather puzzle began to leak out. Someone came on television and claimed that it was because the weakening of the circumpolar jet that ordinarily pins in the polar vortex. That helped some. Then a friend sent me a newsletter about a warm pool of water in the Gulf of Alaska. This was also something I recall reading about in the 70s. From that I was familiar with how that pool turns the jet stream up into Canada at which point it zooms down on eastern United States bringing chilly air with it. I have no problem seeing that an arm of the tropical jet thundering around the warm pool and into Canada in the winter would throw the Arctic jet into disarray and freeing the polar vortex to wreak havoc.
The real question is why that pool is so persistent? Usually it goes away in the fall and the jet stream and the airmass that goes with it assume a cozier route across the US. A possibility is the current solar maximum, weak though it be, but what is the mechanism to warm that pool? The Gulf of Alaska is a long way north for it to be warmed much directly by the sun this time of the year.
Then came another startling observation my friend noticed. Scientists were finding that strong westward passage of air along the equator was sinking atmospheric heat into the Pacific along the equator +/-10 degrees latitude. This seems to be a new phenomenon and worries me. Does it mean that the atmosphere is so hot from global warming that processes are active to cool it by sinking the excess heat we caused into the ocean? Can salmon and other Pacific fish survive such a thing?
Since then I have been thinking that this could be the warming mechanism for the Gulf of Alaska pool. If the Pacific is being warmed by winds that are sinking atmospheric heat into both atmosphere and ocean, then the Japanese Current could be drawing that warm water around the Pacific with the resulting warm pool in the Gulf of Alaska. The next bit of news I will be watching for is for someone who studies Pacific temperatures to confirm that the latter link is in truth the case.
If all of that is true, then there is little mystery about why the winter is cold in eastern US. It also might suggest that the condition will persist until the thermodynamic balances between atmosphere and ocean, equator and pole, are redressed. How long could that take: ten years, a 1000 years? Perhaps a simulation might be able to work the 10/1000 years question out providing a bit of window on the future.
I have always thought that it is one of the great ironies of the current age that people in eastern US, perhaps the greatest perpetrators of global warming in the world, are being cooled by global warming. This is something else that has been going on for a long time, maybe since the 80s. It interesting that the cooling process has turned mean this winter and bitten us with stinging cold. This is not the type of lesson in global warming we are used to getting from the weather.