By Greg Kornelis
In the past couple weeks, global air currents forced an arctic air mass known as the “Arctic Vortex” onto the United States as far south as the State of Georgia. Meteorologists and newscasters have been seen on television throwing cups of hot water into the air to show how it spontaneously turned to snow in the sub-zero temperatures. Areas of the Midwest even experienced windchill factors of -60°F. All of this has prompted hardline climate-change deniers to call the validity of “global warming” into question.
Though it may be cold outside now and again, the weather we experience day to day is not representative of a changing climate by itself. The science of climate change deals with long term average temperatures which have risen steadily over the last 30 years. 97% of climate scientists agree that the earth’s atmosphere is warming.
But don’t take my word for it. Ask a polar bear! In a study of polar bears and arctic sea ice along the western shores of the Hudson Bay it was shown that sea ice has been retreating earlier and advancing later over time. This has stranded bears on the shore, reduced their time to hunt seals on the ice, reduced cub production, and deteriorated adult health. “It’s survival of the fattest,” concluded lead author Dr. Seth Cherry (though himself not a polar bear). The bears have also seen a declining trend in Arctic sea ice cover since satellite imaging began 35 years ago. The 2013 sea ice maximum was the fifth lowest ever recorded, and the 2013 minimum was the sixth lowest(up from the record lowest of 2012). Even more, the polar vortex’s recent position over the United States and subsequent sub-zero temperatures may have been influenced by warming patterns in the arctic. When stored heat energy in the polar region escapes into the atmosphere it can push arctic weather systems further south than normal.
The record low temperatures over much of the eastern United States have reminded many of what cold weather is like. According to NASA Goddard Institute’s Gavin Schmidt, the city of Minneapolis experienced 14.7 days of temperatures below -10°F per year in the 1970’s. In the last decade those temperatures were reached only 3.8 days per year. “The real story is that people have forgotten what cold weather is like.”
Another study, published in Nature Climate Change, found that the weather we experience today alters the way we remember past weather events and our concern over climate change. For example: if it’s cold outside, we’re more apt to remember other cold days than the sweltering ones, thus we become less anxious about the overall warming global climate. The lead author of this study, Lisa Zaval, relents that “we have not found a method to combat this effect.” But, I think I might have an idea how to remind people that global warming is in fact a very real phenomenon: Ask your local hungry polar bear.
Zaval, L. et al. How warm days increase belief in global warming. Nature Clim. Change. 2014/01/12/online
Cherry, S. G., Derocher, A. E., Thiemann, G. W., Lunn, N. J. (2013), Migration phenology and seasonal fidelity of an Arctic marine predator in relation to sea ice dynamics. Journal of Animal Ecology, 82: 912–921. doi: 10.1111/1365-2656.12050