There is no denying that this winter has been unusually warm so far. All across the east coast there has been a lack of cold weather, which means a lack of snow. Even here in Rochester there have only been a couple of light snow falls so far. This unusual warm weather has led to a lot of people claiming it’s global warming. But that’s not exactly true.
Global warming is a gradual increase in the overall temperature of the earth’s atmosphere generally attributed to the greenhouse effect caused by increased levels of carbon dioxide, chlorofluorocarbons, and other pollutants. The emphasis in this situation should be on the “gradual increase”. Each year, increasing CO2 levels warm the planet just a tiny bit from the previous year. While humans may not be able to feel these temperature changes, these small incremental changes over many years are having huge environmental impacts. Over the past fifty years, the average global temperature has increased at the fastest rate ever in recorded history.
But just because we are having an unusually warm winter this year, it is not the result of global warming. Meteorologists are attributing these record breaking temperatures to two different climate phenomena: an exceptionally strong El Nino and the Arctic Oscillation trapping cold air in the North Hemisphere. By themselves, each of these climate patterns could cause unusually warm winters, but together they are causing exceptionally high temperatures.
Arctic Oscillation is a change in air pressure at the North Pole which affects how far south cold air travels from the Arctic. Fluctuations in arctic oscillation are determined by the polar vortex. The polar vortex is a ring of cold winds around the north pole. In a low pressure state, the winds are kept close to the north pole. In a high pressure state, the winds can be pushed away from the poles. Right now, the polar vortex is in a low pressure state, keeping cold winds that would normally cool the Northern Hemisphere close to the North Pole.
El Nino is also adding to the warm winter temperatures. El Nino is large-scale ocean-atmosphere climate interaction. The warm waters heat the air, causing a rise in temperature. This periodic warming in sea surface temperatures occurs across the central and east-central Equatorial Pacific. El Niño-related winds are pushing warm air in from the Pacific.
So while yes, climate change is a very real occurrence, it is not the cause of this year’s abnormally warm winter temperatures.
Photo source: commons.wikimedia.org
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Written by Alyssa Lemire, Class of 2017