Claiming To Be Able To Blame Weather Events On Global Warming

This is not a big story, but it's worth highlighting because of the pernicious effects of science journalism, which suffers from the same faults as political journalism. Emphasis on extremes, cheerleading, opinion masked as fact, over-certainty, no deviance from official narratives, and so on and so forth.

We'll walk through one of these pieces for the fun of it and see what lessons can be drawn. (Thanks to Benny Peiser at the Global Warming Policy Foundation for the tip.)

On the official American Physical Institute site is the article "Pinpointing the Roots of Extreme Weather Events", which boasts, "A statistical method for fingerprinting the patterns of heat waves and cold spells could reveal whether climate change caused an extreme weather event."

This is something regular readers will be familiar with. I mean, claims to be able to identify whether some bad (never good) weather event can be blamed on global cooling a.k.a. global warming a.k.a. climate chance a.k.a. whatever. We saw in the paper "The Climate Blame Game: Are we really causing extreme weather?" this can't be done with any reasonable degree of certainty.

How about here?

Article starts by saying it was hot out west somewhere, and that the temperature was "unprecedented". By which they could have only meant it was slightly above the small number of records kept over a limited number of years using modern measuring equipment. Anyway, there is our "bad" event.

We now have to blame the bad---never good!---event on people, else it becomes a non-story. The author obliges: "Climate models indicate that extreme heat waves---prolonged periods with sustained temperatures above average---will likely occur more often and with increasing severity if Earth’s overall temperatures continue to rise."

This "likely" is transformed into near certainty by appearing next to the following sentence, "But teasing out whether climate change caused a specific heat wave or cold spell remains difficult."

Impossible, I say, because the climate models can't be trusted. (More on this another day: even modelers are being forced to publicly admit this.)

Skip that. Author says IDing global cooling as the culprit

could become easier with a new method from statistical physicists Valerio Lucarini of the University of Reading, UK, and Vera Gálfi of Uppsala University, Sweden. Their method allows the user to uncover what set of characteristics define an extreme weather event for a specific climate and then to use those fingerprints to determine whether a real event, such as any of the 2021 heat waves, was caused by the natural variability of the climate or by global warming.

Okay, sounds interesting enough. Maybe if it took into account the gross over-certainty of the models' future forecasts something good could come out of it.

The ability to make these inferences comes, Lucarini says, because of the similarity of the patterns of simulated extreme events. The analysis shows that these events all sit in the same “universality class”---a term for a collection of things that have converging properties...

The predictive power of the model also sets it apart from others that aim to pinpoint the cause of a specific extreme climate event. Lucarini says that other methods are largely empirical, meaning that the tools can indicate the likelihood that a past extreme event was caused by climate change but cannot predict the probable occurrence of future such events. “Our methodology allows us to do that,” he says.

The author also says the method uses the same kinds of climate models the IPCC uses. So this is serious stuff! Does it work?

The team tested the model for two extreme temperature events from 2010: a month-long heat wave in Russia, where temperatures soared to 20 °F (11 °C) above average, and a cold spell in Mongolia, which brought heavy snow and temperatures of -58 °F (-50 °C)...The team found that both events were expected from the natural variability of the climate.

Say, it seems their method does work. Let's go and look at the actual paper and see what's what. It's the peer-reviewed "A large deviation theory-based analysis of heat waves and cold spells in a simplified model of the general circulation of the atmosphere" in the Journal of Statistical Mechanics: Theory and Experiment.

I'll skip all the probability (which any trained statistician can follow with ease) and focus on the physical model used, and which is key, and which the press piece said was like that used by the IPCC.

Compared to a full atmospheric general circulation model, moist processes are omitted, and simple parameterisations are used to account for the effect of friction (Rayleigh friction), diabatic heating (Newtonian cooling), and diffusion...

We run the model in a simple symmetric setting (usually referred to as an aquaplanet), i.e. without orography. We remove the annual and diurnal cycle, and use a symmetric forcing with respect to the equator...

Ah. A toy. The model is a toy, resembling our real atmosphere and planet in the same way the spinning globe on your desk resembles the plate tectonics of the real earth. If the globe was one big ocean.

So they ran their toy model, a not unfamiliar practice in physics, and not useless to learn from, and discovered the toy had certain statistical properties.

Since the toy has nothing really to do with the actual atmosphere, its statistics won't either. Maybe the technique of drawing those statistics might someday be useful if actual models become good enough to rely on. Until then, it's all, as they say, academic.

Yet it will still be difficult for most to not draw the conclusion that Something Important Happened Here, and that global cooling etc. is a problem. Which is the point of the news article.

I don't mean to suggest the motives of all involved were anything less than earnest. I do mean to say that we could do with a lot less journalism.

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