As I write this post, here in the Philadelphia area we are experiencing hopefully the last day of a record-breaking 2-week stretch of extremely frigid temperatures. And I can hear the voices of climate science deniers snarkly saying, “well, so much for global warming” and think back to Senator James Inhofe throwing a snowball in the Senate chamber to make a point that extreme winter weather disproves climate change – when in fact it proves just the opposite! You can certainly choose to disregard the consensus of 97% of climate scientists that human activity is the major factor in the rising global surface temperatures but as Neil deGrasse Tyson has said, “Science doesn’t care what you believe.”
Let’s think about that for a moment. We’ve all heard of the dreaded “global vortex” and that it is somehow responsible for this latest extreme cold snap. The global vortex is nothing new. What it is is the circular polar winds which serves to keep the arctic air mass confined to, well, the arctic region. What is new, according to recent research, is that the polar vortex seems to be weakening due to the rapidly rising Arctic temperature resulting in reduced amount of Arctic sea ice allowing more heat to escape from the ocean. As a result the polar vortex is seen to slip southward more frequently. And so we turn up the heat and try to prevent our pipes from freezing.
According to NASA, 16 of the 17 warmest years on record in the 136 years of record keeping have occurred since 2001 and again, scientific consensus is that human activity causing increase in greenhouse gases is the most likely cause.
And as for the seeming disconnect between rising global temperatures and more intense snowstorms, It actually makes scientific sense – the maximum amount of water vapor that the atmosphere can contain increases with temperature. This increase has been 4% over the last 30 years. Therefore, there is more moisture to invigorate storms; if the atmosphere is cold enough this moisture will fall as snow. This effect will typically intensify all storms whether the result is rain leading to increased flooding chances or more intense snow storms.
But what of the “Bomb Cyclone” we experienced last Thursday? It actually is not all that uncommon; the meteorological term is actually bombogenesis also called explosive cyclogenesis which is defined as a extratropical cyclonic low-pressure area. Coupled with the dreaded global vortex we’ve been experiencing made it quite an event this past couple of weeks.
Stay warm everybody!