Going to Extremes

Amidst the scarcely believable frenzy of climate change denial which has taken hold in sectors of American politics, to say nothing of the equally scarcely believable silence from the White House, we need to be reminded that there are sane and steady political voices in that country, however difficult it is for them currently to gain a hearing. Representatives Edward Markey and Henry Waxman recently had the minority staffs of the Committee on Natural Resources and the Committee on Energy and Commerce prepare a report for them Going to Extremes: Climate Change and the Increasing Risk of Weather Disasters (pdf here). It’s now available as a Kindle edition and in short compass reports the scientific case that global warming is shifting the odds towards extreme events.

Evidence is mounting alarmingly. Over the last several years a barrage of extreme weather events in the US and the world has been consistent with what scientists have been predicting from global warming. “Indeed this summer US weather was almost apocalyptic.” The introduction mentions some of the events of the past two years, noting that NOAA has recently concluded after looking through 50 years of weather data that droughts like the recent 2011 Texas drought are roughly twenty times more likely because of global warming. “Global warming has stacked the deck with extra jokers.”

The report zooms in on the multitude of extreme weather events in the US in 2012 which are consistent with scientists’ understanding that global warming is increasing the odds of heat waves, heavy precipitation, droughts and wildfires.

Extreme record-breaking temperatures abound. Drought has been severe in many states, with very adverse effects on crops.  Wildfires have been well above average in extent. Severe storms have hit in several areas. Low water levels have affected rivers. Water temperatures in the Great Lakes and the northeastern Atlantic have been exceptionally high. The total costs of 2012 extreme events are not yet known, but may rival the record $55 billion in 2011, also a year of severe weather disasters.

The US experience has been part of many global weather extremes in recent times, some of which are briefly highlighted in the report.

The predictions of scientists are outlined. Global warming will bring more record-breaking heat, with deleterious effects on food and agriculture production, human health and tourism. Regional rainfall patterns will alter with dry areas getting drier and wet areas wetter. There will be larger, longer-lasting and more damaging wildfires. Global food security may be threatened.

The report concludes:

The links between climate change and extreme weather are abundant, robust and well-documented in peer-reviewed scientific studies. The authoritative science organisations active in the relevant disciplines, including NASA, NOAA and the US National Academy of Sciences, have consistently confirmed the connections between climate change and extreme weather.

Many types of extreme weather, like heavy downpours and heatwaves, have increased in severity and frequency across the globe in recent years. This increase is directly linked to the changes in the Earth’s climate system driven by heat-trapping gases from burning fossil fuels.

…Climate change has contributed to shattered records and unprecedented weather catastrophes, like those the United States has experienced this summer.

There’s nothing in the report to surprise those who regularly follow what scientists are saying on the subject, and many of the footnoted references will be familiar to Hot Topic readers. The report’s significance is in its provenance, revealing that at least some US politicians wish to treat climate science seriously. The attribution of weather events to human-caused climate change is not a simple matter because of natural weather variability and the part played by natural factors such as El Nino and La Nina. But the report follows the careful science which considers it is now able to discern shifts in the frequency and severity of extreme weather events that evidence the effects of global warming.

Markey and Waxman have done nothing more than pay rational attention to well-attested science. Why that should appear politically combative is a question that only the proponents of denial and delay can answer, and what one sees of their answers contains little or no reference to the actual work that scientists are engaged in. It’s hard to see a way forward on the US political front as it is presently configured, but good to see the steadfastness of the two congressmen in representing the reality with which the country will eventually have to deal.

7 thoughts on “Going to Extremes”

  1. That statement, “NOAA has recently concluded after looking through 50 years of weather data that droughts like the recent 2011 Texas drought are roughly twenty times more likely because of global warming” is attention grabbing, but because NOAA didn’t look through 50 years of weather data, no one should be saying or repeating it.

    It isn’t just a mistake made by some Congressional staff – the “twenty times more likely” reverberated in media reports and on the internet at the time until many thought scientists had studied weather patterns and found this.

    Things seemed to start with a NOAA press release which stated under a headline “Findings”, that:

    “La Nina related heat waves, like that experienced in Texas in 2011, are now 20 times more likely to occur during La Nina years today than La Nina years fifty years ago”

    Now the NOAA press release says the source for this “finding” is a “complementary article… published by AMS”, i.e: Explaining Extreme Events of 2011 From a Climate Perspective. which is an assembly of a number of studies with some concluding commentary. The study that is the source for the “finding” starts on page 1052. This is the Rupp et.al. study Did Human Influence on Climate Make the 2011 Texas Drought More Probable?

    Here, Rupp et.al. explain what they found and how they found it. They took data from four years, i.e. what they thought were roughly similar La Nina years to 2011, i.e. 1964, 1967, 1968, and 2008 (but not 2011 “because simulations for 2011 were not available”), and ran a “very large ensemble of simulations from a global climate model (GCM)”, using “public volunteered distributed computing” resources to “obtain an ensemble size that is large enough to examine the tails of the distribution of climate variables”.

    They added things up and found that for those La Nina years, if you ran model run after model run until the cows came home, it was 20 times more likely that the model would spit out a humongous Texas 2011 sized drought in the 2008 model runs than for runs set up with the 1964, 1967, or 1968 data.

    This is not “looking through 50 years of weather data”.

    I’m not sure exactly how I would have written the NOAA press release or the Markey-Waxman report, but because both depend on the finding of the Rupp et.al study, I would have tried to slide in the word “modelling study” or “model” and definitely steered very far away from anything that sounded like “looking through 50 years of weather data”.

    1. So what are you actually saying Mr. Lewis? Do you have any evidence that contradicts NOAA’s findings of a 20 times greater likelihood of these extreme weather events today than over historic times out of the past 50 years before AWG got to today’s levels?

  2. In contrast to the frenzy of denial, in the last two or three days I watched two American TV programs where climate change kept being mentioned as something that had to be addressed.

    The first was PBA News. I had been wondering if the term Climate change was taboo on that program when they ran a lengthy account of Chicago’s green roof program where climate change was part of the context. The second (can’t recall the program) featured a man who had covered his house with solar PV and to balance up a bit and get those last few dollars off his power bill had installed a wind turbine on his 1/6th acre property. His rational – he did this as a demonstration and a service to the planet. Why were his neighbours objecting to the shadows the turbine threw on their properties? A spokesperson for the neighbours acknowledged what he did as right except that the turbine was better sited in a paddock or a larger property. The council too had granted the permit because climate change should be addressed but regretted they had not considered the small size of the property. In the meantime the windmill was not in operation but of course still casting a shadow. In all this there was not a denialist in hearing. I think I heard the name ‘Long Beach’ as the location somewhere in US where this was happening.

    In contrast this evening NZTV ran news on the Arctic low and Antarctic high ice extents, whoever wrote the intro to the item having no idea what they were doing in presenting this as if equivalents. Two scientists explaining the relation of the ozone hole, the circumpolar winds and the ice expansion did not really counter the false impression conveyed by the newsreader beforehand although maps outlining the differences in extent from earlier times were shown for both poles. The info was there admittedly.

    The two American programs showed no taint of denialism nor any extravagant statements. May there be more.


  3. This doesn’t really gel with this article from Roger Pielke Jr

    What about the United States? Flooding has not increased over the past century, nor have landfalling hurricanes. Remarkably, the U.S. is currently experiencing the longest-ever recorded period with no strikes of a Category 3 or stronger hurricane. The major 2012 drought obscures the fact that the U.S. has seen a decline in drought over the past century.

    Such scientific findings are so robust that the Intergovernmental Panel on Climate Change concluded earlier this year that over the long-term, damage from extreme events has not been attributed to climate change, whether from natural or human causes.

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