The 5 Sigma Extreme Weather Event Has Occurred. Has the World Entered Into a New Reality?

Sigma σ Odds (Years)

1 2 : 1

2 21 : 1

3 370 : 1

4 16,000 : 1

5 1, 700, 000 : 1

The last 10 months or so has been marked by a range of intense extreme weather events around the globe, including heat waves and wildfires, atmospheric rivers resulting in flooding, and many of them breaking long standing records.

Some of the events were catastrophic. The record breaking rain in Eastern Australia has killed at least 21 people. Thousands of homes have been left uninhabitable by one of Australia's worst natural disasters in a one-in1,000 year event that occured twice in two weeks.

Look at how high the waters peaked in the recent Queensland Floods (March 9, 2021)

On our scale above, we can measure this as a 3 sigma event. What does that mean exactly? Sigma (σ) is a statistical measure of the chance of the occurrence of an event. A 1 sigma event has a 2 : 1 (two-to-one) chance of occurring. In the context of this article, a one sigma weather event would be expected to happen once every 2 years. A 2 sigma event would likely happen once every 21 years. A 3 sigma event would probably occur a whopping once every 370 years. Thus, the recent once-in-a-millenia Queensland Floods would be classified at a staggering 3.1 sigma.

On June 29, 2021 Lytton, B.C., broke the record for the hottest temperature ever recorded in Canada for a third straight day, hitting 49.6°C. The previous Canadian record for all time maximum temperature was 45.0°C set on July 5, 1937 at Yellow Grass, and Midale, SK. It beat the previous record by a staggering 4.6°C. The following day on June 30, a heat-induced wildfire burned down 90% of the town killing 2 people. According to weathercaster Jeff Beradelli on twitter, the heat dome sigma max for this event was "4.4 - that means it's outside of 99.99% of expected values or a 1/10,000+ chance." In other words, once in every 10 000 years.

But, it's even worse than you think. On March 2022, the Antarctic and Arctic hit temperatures 40°C and 30°C higher than normal, rewriting the record books. The heat dome responsible for the surging heat in Antarctica was intense. According to Dr. Jonathan Wille, a researcher studying polar meteorology at Université Grenoble Alpes, the heat dome was 5 standard deviations above normal. This was a 5 sigma event that should only happen once in every one million seven hundred thousand years. Scientists like Dr. Robert Rohde were shocked and horrified by what until very recently seemed impossible.

Some people have correctly pointed out, that it is too early to tell if we have truly entered into a 5 sigma world. This is but a single data point. That is a fair assessment, and truthfully, I hope these critics are right. Alternatively, it is also possible that the world is entering dangerous territory where the old rules may no longer apply. After all, Lytton, BC and the Antarctic heatdome were not predicted in climate scientist's models.

So, this is the question. Should we continue to sit on our hands and do virtually nothing, or is it time to take immediate serious action? The alarm bells are ringing. We are running out of time, yet the world refuses to act.

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