Every night it seems we here more about a polar vortex which has descended across the country creating snows and record low wind chill temperatures. Yet, at the same time, we have been told that we must take steps to stop and reverse global warming before it is too late to reverse its effects. To the average person these facts seem to be incompatible, but they are not.
Gradually over the last 150 years the average temperature on the planet has increased about 0.6 degrees Centigrade. These changes we recognize as global warming. Climate scientists tell us that this trend will likely continue unabated until elevated to about two to four degrees centigrade by the end of the century. Yet now we are beginning to see vairations in climate that are extreme and hard to predict. Are they connected to global warming? Yes. Storms and unusual weather events occur more often now and with greater intensity. These are occurring more often in the northern than in the southern hemisphere and are probably mostly linked to the significant loss of sea ice in the Arctic, which has lead to major regions of open water especially during the summer months.
These conditions have moderated weather near the nothern Arctic coasts leading to significant melting of permafrost and warmer average temperatures in the north; not warm, but warmer. In the fall and through out winter high pressures occur and may steer cold Arctic air down across the lands, either into North America as is occuring now or into Russia and Siberia as it occurred a few years ago. These stroms are not easily predicted. To some extent they have always occurred, creating intense cold weather either in Northern Canada or in Siberia. Some of this has been thought to be associated with upper level jet streams. However, it is not clear just how this occurs, and how, in particular, storm intensity is being markedly elevated.
The melting of Arctic ice over the last several decades has made it necessary for the Earth to balance the cooling of the excessively heated equator by the polar regions that normally absorb the excess heat, a process that had previously been in balance for centuries–but not without intense stroms. With significant open water now in the Arctic, radiant energy from the sun is more effectively absorbed by the open water rather than being reflected effectively by the white sea ice. As sea ice declines and open water persists for lenghy periods, the rate of sea ice loss has accelerated alarmingly. Geologists and other Earth scientists have predicted the gradual loss of sea ice in the Arctic, but none imagined that the loss of ice would have accelerated as fast as it has. That may be part of the problems we seeing currently.
The best face we can put on the current problem is that the unpredictably intense storm patterns, as well as the widely different patterns of drought and rainfall, are perhaps just beginning to play out. These new and often harsh conditions are not new, but are enough of a change from what we are used to to be recognized as such. In general, the Earth in the last 30-50 years has changed more signficantly that we realize and now the planet must apparently find new ways to take the excess heat from the equator and spread it around the Earth. The polar regions are becoming warmer more rapidly than anywhere else, and as they warm it becomes harder for the equatorial heat to move toward the poles. Indeed, the Earth must find new ways to move toward thermal equilibrium and one of those ways may be for cold air in the Arctic to more toward the equator. The Earth has always used both mechanisms–dips in jet streams that move cold Arctic air to the south, and creation of intense hurricanes near the equator that move hot air gradually to the north — in it’s attempt to come to thermal equilibrium, which, of course, it never reaches.