Extreme weather can be exacerbated by global warming either because the currents of atmosphere and oceans change, or it can be exacerbated through thermodynamics (the interaction of heat, energy, moisture, etc.). Last week’s study dealt with just the thermodynamics. This week’s study presents a method to deal with both.
The authors, Daniel Horton, Noah Diffenbaugh and colleagues used a new technique to tease apart the complex influences of warming on changes to atmospheric circulation. Dr. Horton told me,
Our study focuses on the need to understand the underlying physical causes of extreme weather events, and to systematically test whether the probability of those underlying conditions has changed in recent decades. Events that are so extreme that they fall outside of our historical experience often result from a suite of complex interacting factors. To better understand these factors we’ve developed a method that allows us to partition the climate influences....
The authors show that as the Earth warms, we expect fewer cold temperature events generally. But, in some cases the circulation changes have led to extreme cold outbreaks in some regions. What has happened is that the arctic front, which typically confines cold weather to the Arctic region, has undulated sufficiently to allow cold-air breakouts to the south. Think of the polar vortex from last year.
These findings support the commonly-heard term that has emerged in the past few years of “weather whiplash - wild swings from one extreme to another. Importantly, the authors show that the trends are “statistically significant” and are unlikely just random occurrences.
Read more at More Evidence that Global Warming Is Intensifying Extreme Weather
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