A recent article appearing in The Journal of Climate argues that the recent extreme winters in the Eastern United States are not the result of climate change, as global warming will, in fact, reduce temperature variability over time.
Researchers at ETH Zurich and the California Institute of Technology have shown, through climate simulations and theoretical arguments, that the overall effect of global warming will be to reduce temperature variations. It had been hypothesized by others that the polar jet stream, which is the movement of air north and south several kilometers above the earth’s surface which determines weather patterns broadly, is becoming weaker. That weakening stream, scientists have suggested, could lead to the kinds of temperature extremes we’ve seen in the last two years.
It would seem, however, that the polar jet stream is largely unaffected at this point–or, more accurately, its variations don’t affect us too much. As the differences between temperatures at the poles and in the tropics lessen, temperatures will begin to fluctuate less, not more, over time. Extremes of temperature will become less common, but that doesn’t mean they’ll go away entirely. Likely, we’ll see more extreme warm periods in the future. The article is limited to temperatures, and the authors suggest that we could still see extreme rain and snowfall in conjunction with the warming global climate.
The scientists who authored the study are pursuing further research to see what other effects increasing global temperatures might have. They are focusing on recent European heat waves and investigating why the high pressure systems that cause them aren’t moving. The takeaway of the research is that we have a slightly better picture of what to expect from global warming in the future.