Claim: Extreme weather 4x more likely now than pre-industrial era

Because PlayStation® climatology says so?

The media release is below.

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Global warming has increased risk of record heat, say Stanford scientists

Drought shriveled crops in the Midwest, massive wildfires raged in the West and East Coast cities sweltered. The summer of 2012 was a season of epic proportions, especially July, the hottest month in the history of U.S. weather record keeping.

And it’s likely that we’ll continue to see such calamitous weather.

In the north-central and northeastern United States, extreme weather is more than four times as likely to occur than it was in the pre-industrial era, according to a new study by Noah Diffenbaugh, a Stanford associate professor of environmental Earth system science, and Martin Scherer, a research assistant in the department.

Diffenbaugh and Scherer found strong evidence that the high levels of greenhouse gases now in the atmosphere have increased the likelihood of severe heat such as occurred in the United States in 2012.

The researchers focused primarily on understanding the physical processes that created the hazardous weather. They looked at how rare those conditions were over the history of available weather records, going back over the last century.

Then, using climate models, they quantified how the risk of such damaging weather has changed in the current climate of high greenhouse gas concentrations, as opposed to an era of significantly lower concentrations and no global warming. Their findings don’t pinpoint global warming as the cause of particular extreme weather events, but they do reveal the increasing risk of such events as the world warms.

“Going forward, if we want to understand and manage climate risks, it’s more practically relevant to understand the likelihood of the hazard than to ask whether any particular disaster was caused by global warming,” Diffenbaugh said.

In 2012 alone, the United States suffered 11 extreme weather events that each caused at least $1 billion in damage. “It’s clear that our greenhouse gas emissions have increased the likelihood of some kinds of extremes, and it’s clear that we’re not optimally adapted to that new climate,” Diffenbaugh said.

While Diffenbaugh cautions against trying to determine whether global warming caused any individual extreme event, the observed global warming clearly appears to have affected the likelihood of record heat, according to Diffenbaugh and Scherer.

The study, looking at the likelihood of July 2012 U.S. temperatures recurring, is part of a larger report edited by scientists at the National Oceanic and Atmospheric Administration (NOAA) and published Sept. 5 in the Bulletin of the American Meteorological Society. The report includes studies of a dozen 2012 extreme weather events by research teams around the world, about half of which found some evidence that human-caused climate change contributed to an extreme weather event.

Close study of extreme weather events can help quantify the likelihood that society will face conditions similar to those that occurred in the summer of 2012, thereby informing efforts to reduce vulnerability and increase resilience. Diffenbaugh argues that the new results can also help to quantify the true cost of emissions to society, since the cost of the disaster is measurable.

“Knowing how much our emissions have changed the likelihood of this kind of severe heat event can help us to minimize the impacts of the next heat wave, and to determine the value of avoiding further changes in climate,” Diffenbaugh said.

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7 thoughts on “Claim: Extreme weather 4x more likely now than pre-industrial era”

  1. How about publishing a copy of the paper itself along with this so we can see what they actually did without having to dig up the paper. All these comments seem to just be based on the media release so they really say more about the predisposition of the commenter than the research. No real scientist would draw any conclusions from a press release so as far as scientific rigor, did anyone read that paper? Or are you just promoting your personal opinion?

  2. If I were a columnist I’d start every column with “Global circulation models were wrong about…”.

    I’d have no shortage of column subjects for many years.

  3. “In 2012 alone, the United States suffered 11 extreme weather events that each caused at least $1 billion in damage. ‘It’s clear that our greenhouse gas emissions have increased the likelihood of some kinds of extremes, and it’s clear that we’re not optimally adapted to that new climate,’ Diffenbaugh said.”
    1. Define “extreme” weather event with a consistent and measurable weather metric. The dollar cost of a weather event relates to what is in its path more than the force of the event itself. As the world becomes more wealthy, there’s more property and product to be damaged and those properties and products are more valuable.
    2. Using the validated metric, select several areas with good weather records and see if you can evaluate the incidence of weather events that meet the metric. Not dollar cost, not newspaper articles, not a diary entry: use the event only if the weather element has the validated metric.
    3. Come and tell me what you got.
    You must meet steps 1-3 to say if events that meet the extreme metric are increasing or decreasing. Then you can try to explain the trend if there is one.
    According to many articles linked here, the weather events for which we have the best metrics (and they are short in rigor too) are trending down if they are trending at all.
    As for being adapted to these events: deaths due to weather disasters have trended down for a hundred years or more. I’d call that adaptation.

  4. How about:
    Droughts are worse now because we have more people using and re-routing the water.
    If forest fires are worse now, it’s because the Forestry service budget was reduced or mismanaged. Also, we have more forest now than we did 100 years ago.
    Cities are hotter now because of the urban heat island effect.

  5. Eight “science” writers at the LAT’s tripping over themselves trying to present this story first to their nutcase editor.

    What? Oh, excuse me . . . she assigned it.

  6. “Their findings don’t pinpoint global warming as the cause of particular extreme weather events, but they do reveal the increasing risk of such events as the world warms.” A bit of a logical fallacy. We can’t prove it therefore it must be so. I wonder how they come to this conclusion with the decreasing frequency of extreme weather events.

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