Parts of North America are seeing a record-breaking cold spell with temperatures reaching as low as 30 degrees Celsius below zero in the northern US, and even colder in Canada.

The cause is said to be a polar vortex, a massive cell of cold air that normally resides over the North Pole and is kept in check by the jet stream. This year, however, some warmer air from the south travelled to the Arctic, invaded the vortex and split it into pieces, one of which has made its way south into North America, where it is keeping millions indoors for a few days.

Residents of Hong Kong will remember the winter of 2016 when we also experienced a polar vortex. Dozens of people were injured on the upper slopes of Tai Mo Shan when frost-seekers got more ice than they bargained for.

Sliding down the slope at Tai Mo Shan in 2016.

Although our temperature only got down to about minus four degrees – and that was at the top of a mountain – it reveals the strength of a polar vortex when it can bring such low temperatures down here in the sub-tropics.

Ironically, scientists believe these enormous blasts of freezing air that have been heading our way recently are actually a symptom of global warming. Until recently, warm air in the lower latitudes had not been able to penetrate polar regions.

However, as the Earth heats up, warm air is now able to do so. And when it does, sometimes it results in a polar vortex heading south where people live in Asia, Europe and North America.

These cold temperatures are counter-intuitive in an era of global warming. This irony illustrates a point about not only the differences between weather and climate – the former being short-term and the latter long-term – but also the frailty of human logic.

Witness Donald Trump’s reaction to the polar vortex in a recent tweet:

Mr Trump is a well-known climate change denier. He has even referred to it as a hoax created by the Chinese in order to make U.S. manufacturing non-competitive.

So where is the weakness in human logic here? Well, the chain of logic goes something like this.

Super cold air is a dramatic event. Some people in the affected regions go outside and freeze their buns off. Their frozen fingers and toes have an emotional influence on their logic. As they experience the painful cold, they think, “So much for global warming if temperatures can reach record-breaking lows. Trump is right.”

Photo: GovHK.

The cognitive error here is called “base-rate neglect”, in other words, prioritising near-term events over long-term ones. Many of Trump’s supporters basically ignore the forest for the trees and confuse weather for climate. The base rate here is the collective temperatures over a period of decades, if not centuries. And it is this base rate that clearly shows temperatures are rapidly rising and that climate change is real.

As for the many more record high temperatures being set on a frequent basis, as well as the increasingly destructive typhoons and hurricanes we are experiencing, well, that’s last week’s or last year’s news. And besides, evidence that does not align with one’s worldview is easily discarded or forgotten.

I have even found myself making the same error. Recently I mentioned to a friend that this was the first winter here in Hong Kong that I have not used a heater. Then I used this as evidence of global warming.

Clearly, the temperatures during one winter, and the use of a heater or not, cannot serve as evidence for climate change. However, I make this confession to illustrate the power of base-rate neglect. Even those who are aware of the potential for faulty logic can still fall victim to it.

US President Donald Trump. File photo: White House.

Returning to Trump, he has capitalised on this cognitive bias called base-rate neglect harboured in all of us and successfully politicised an issue that, at its core, is atmospheric.

Either he is a very smart man and understands that many of his naïve supporters will witness the cold snap and buy into his flawed logic about climate change. Or, perhaps he is a naïve victim of base-rate neglect himself, and he really believes that the cold air is evidence of a climate change hoax.

My guess is that it’s the latter.

Paul Stapleton

Paul Stapleton is a long-time resident of several countries in Asia, where he has been teaching and researching at various universities. He writes about environmental, social and educational issues. In his op-eds, Paul's goal is to shed some light on issues of interest as well as generate a bit of heat. Paul’s website is at Academic Proofreading Plus.