“It’s a Once in 500-Years Storm!”
Editor’s Note: This column was first published on David Houle’s Substack.
“This was a once-in-a-generation event!”
“Once in a millennium event.”
“An unprecedented event.”
Please stop with all this stupid language about storms and floods! Please!
Every time there is a ‘super storm’ or some catastrophic event, the local authorities have been saying exclamatory statements about how historic the event was.
This implies that there was nothing to be done. That it was unpredictable. That no matter how competent the county/city/state officials are, we are off the hook because this wasn’t predictable.
Rubbish!!!
All collected weather data is from the past; climate change is of the present and future. The only one of the above quotes that is true is the last one: “An unprecedented event.” Why? Because what is happening on Spaceship Earth hasn’t happened for close to 1 million years, so no recent (last 150 years) weather records occurred before the current warming.
The science behind these comments is not based upon actual history of listed storms, it is based upon statistical probability. Here is an explanation from several years ago on CNN:
Let’s cover a few common sense issues: Despite sophisticated modeling and projections, we really have no idea what the weather was in any specific point for most of global history, unless someone decided to scribble down the details on a piece of papyrus somewhere. (Weather, of course, being separate from climate, which is a longer-term pattern. For instance, we may know it was generally rainy in the United Kingdom in the 1800s, but we don’t know for sure what the exact weather was on September 19,1855, unless someone recorded it.)
The climate is a long-term average of weather,” says CNN meteorologist Brandom Miller. “So you can make more precise projections over the longer term with higher confidence.”
Given that, the whole business of weather statistics relies on two things: Our modern recordings of weather history and the informed assumptions one can make from them.
“A 1 in 500 year event is really based on how frequently an event is likely to reoccur based on its percentage likelihood based on the historical record in that location,” Miller says. “Given that we only have 150 years of records in the US, some of the extreme low frequency events may have never occurred before, but are based on extrapolations of what we do have on record.”
Rather than imagining one particular rain event happening every 500 years, think of it this way: There is a 1 in 500 chance of this rain event happening in a given year, or a 0.2% chance. Put that way, the probability of it happening year over year stays the same.
“Something that has a 20% chance of occurring in a given year, or 1 in 5 chance, would be a one in five year event,” Miller says. “But of course, these can happen much more frequently than that. There is still a 20% chance that it happens the next year, or even at another point that same year. So that can be very confusing to people.”
If specific measurements of a storm happen once every 100 years, that means that there is a two-percent chance of it happening in any year. So, in predicting weather in this Age of Climate, the past is not prologue. The recent past is no indicator of what might happen. For example, if the “once a century storm” happens every three years, then the percentage goes from 2% to 33%. That is the correct way to forecast weather now.
In 2018, this was published https://www.wunderground.com/cat6/3-Highest-Volume-US-Rainfall-Events-Record-Have-Happened-Past-3-Years Seven of the top ten disasters have happened since 2000, and the other three happened in the 1990s. Several storms that would have made the list have occurred since 2018.
https://news.un.org/en/story/2021/08/1097362
In 2021, the UN Secretary General called the climate crisis a “Code Red for Humanity.”
To quote from this UN report:
“The report, prepared by 234 scientists from 66 countries, highlights that human influence has warmed the climate at a rate that is unprecedented in at least the last 2,000 years.
In 2019, atmospheric CO2 concentrations were higher than at any time in at least 2 million years, and concentrations of methane and nitrous oxide were higher than at any time in the last 800,000 years.
Global surface temperature has increased faster since 1970 than in any other 50-year period over at least the last 2,000 years. For example, temperatures during the most recent decade (2011–2020) exceed those of the most recent multi-century warm period, around 6,500 years ago.
Meanwhile, global mean sea level has risen faster since 1900, than over any preceding century in at least the last 3,000 years.
The document shows that emissions of greenhouse gases from human activities are responsible for approximately 1.1°C of warming between 1850-1900, and finds that averaged over the next 20 years, global temperature is expected to reach or exceed 1.5°C of heating..
The reason I am using the 2021 report is that, three years later, the planet has already warmed to 1.5 degrees Celsius. In 2021, the thinking was that it would take us 20 years until we crossed that threshold. Two years ago!
The vaunted, much-ballyhooed “2015 Paris Climate Accord” that 195 countries committed to support is already dead. The first 28 COPs have been failures. COP29 will happen in November of this year – another failure in mobilizing a global political will to change.
This column is being written as the horrible toll of Hurricane Helene is all over the news. Local officials have called Helene a “once in a century storm” or a “once in a millennium storm.” (Editor’s Note: major hurricane Milton made landfall in Florida shortly after this was written).
Instead, if officials were to speak the climate truth and call Helene a storm, that would possibly happen once every three years, people would react differently.
They would certainly be more receptive to evacuation.
They would probably think about moving away.
They might start to understand how severe our climate crisis is.
To paraphrase Bob Dylan:
“You don’t need a weatherman to tell you which way the climate crisis is going.”
