21 March 2018
Just because it seems like it, doesn’t mean it is so. A subjective feeling means nothing more than,” I wonder if this is true”. Science goes by the data, so when it seems like there have been a lot of snowy winters in the Northeast U.S. over the last couple of decades, you need to see if that has indeed been the case. Then (and only then!) can you ask, what might be the reason? Is it just a natural series of cold and snowy winters or is the warming planet involved?
Dr, Jennifer Francis at Rutgers was one of the first to look at this question and ask if the loss of Arctic ice was changing the weather patterns. Since then, a number of studies have shown evidence that it is true and that the loss of Arctic ice may be involved. What was at first looked at with skepticism seems to be growing in acceptance. The latest study is a paper in Nature Communications by Francis who co-authors with Judah Cohen and Karl Pfeiffer. The paper is open source and you can read it here.
In a hurry? Read the abstract below:
Recent boreal winters have exhibited a large-scale seesaw temperature pattern characterized by an unusually warm Arctic and cold continents. Whether there is any physical link between Arctic variability and Northern Hemisphere (NH) extreme weather is an active area of research. Using a recently developed index of severe winter weather, we show that the occurrence of severe winter weather in the United States is significantly related to anomalies in pan-Arctic geopotential heights and temperatures. As the Arctic transitions from a relatively cold state to a warmer one, the frequency of severe winter weather in mid-latitudes increases through the transition. However, this relationship is strongest in the eastern US and mixed to even opposite along the western US. We also show that during mid-winter to late-winter of recent decades, when the Arctic warming trend is greatest and extends into the upper troposphere and lower stratosphere, severe winter weather—including both cold spells and heavy snows—became more frequent in the eastern United States.
If you look at the conspiracy sites on Facebook or Twitter, you might think that scientists are arguing about whether the sun is influencing our warming, or if carbon dioxide is good for you (It’s not). You might even hear that the recent warming is just the Earth coming out of the last ice age (That was around the time of the beginning of the Egyptian Old Kingdom). Those are things that the science community laughs at because they are just silly.
Instead, they’re asking questions like the paper above covers, and they’re asking if we have any chance of staying below a global rise of 2°C. That is the subject of a reply to a previous paper in Nature Geoscience that Dr Michael Mann and his co-authors published this week. (Note: this is behind a firewall but available at a major library)
That’s the real science that’s being talked about by the grown-ups.
As for the snow tomorrow from Maryland to Boston? There really is no such thing as too much snow IMHO!