17 February 2014

Discussion of Extreme Events on Colorado Public Radio

You can hear Kevin Trenberth and me discussing extreme events and climate change on Colorado Public Radio. The audio can be found at the link at the top of that page.

In the interview I essentially reflected the IPCC SREX and AR5 views on climate and extreme events. Here is an except from the CPR news story that accompanies it:
After big weather events, the question that often comes up is: "Is climate change responsible for this?" That question has popped up a lot in Colorado recently given massive floods and fires over the past year.

In September 2013, devastating floods hit the Front Range and, less than a year ago, the Black Forest wildfire wiped out more than 500 homes near Colorado Springs.

Colorado hasn’t been alone in its extreme weather misery: Hurricane Sandy ravaged the East Coast in 2012, blizzards and snowstorms tortured the Northeast in 2013 and the current severe drought in California means ski resorts haven’t opened and ranchers are selling off their herds.

Are all these events just Mother Nature cycling through her natural mood swings? Or is it, as some scientists suggest, that the human influence on our climate is causing these weather catastrophes?

Kevin Trenberth, a distinguished senior scientist at the National Center for Atmospheric Research, and environmental scientist Roger Pielke Jr., director of the Center for Science and Technology in Boulder, disagree on the answer.
Comments welcomed!


  1. Well, global warming, and I presume global cooling, as well as climate change, and, of course, weather, are now interchangeable. The anthropogenic qualifier is routinely dropped for what must be considered a simpler problem set. Trenberth is focused on emotionally appealing imagery, while Pielke's responses are lackadaisical, and CPR emphasizes each accordingly. As for the discussion, it could have been recorded as two monologues. Perhaps that's the effect CPR intended. Professor, I think they like you, but disagree with your methods.

  2. I feel like the key to the debate might be Trenberth's last statement. Who has the burden of proof in this case. I'd argue it's still on those who state that they should be "proven wrong that climate change isn't impacting a certain event"...if only because we've had other severe events of similar magnitude before.

    It's also a bit of a cop out because Trenberth knows that you can't prove him wrong for the same reason he can't prove himself right. The uncertainty is just too high right now in most circumstances.

    But as Roger points out...it's irrelevant. We have to make decisions based on low certainty.

  3. I agree with Dean that the onus should be on Trenbeth to prove that all weather events are affected by climate change but the point the interviewer missed is that it does not matter. You want to start doing "something" then make non-fossil energy cheaper and maybe do some research to see what that would mean. For example, if you want to use wind mills for a major portion of our energy use then what else do you need. Supporting generation over the very short term, storage over the diurnal cycle, and seasonal storage are three issues I want to see addressed. It seems to me that spending money to determine if those are insurmountable problems is more appropriate than throwing money at current technology hoping it will somehow become cheaper.

  4. CNY Roger:

    We also have to be honest about the environmental impact of "green" technologies, throughout their evolution from recovery to reclamation. The current marketing hype forced a misalignment in development, in part through obfuscation, and in part through shifting. There is a popular misconception that useful energy production is not disruptive and that it is renewable.

  5. Presumably those who are OK with decision making based on the kinds of "uncertainty" that climate science ahs left us with will be OK with the terrible costly and wasteful outcomes of the same.

  6. Trenberth: "SREX is a sham."

    Makes me think of False Balance :)

  7. John Vidal contacted me this week to ask:

    "Is the extreme weather than we’ve been experiencing around the world in the last few months linked to climate change or is it individual natural phenomenon and nothing unusual?"

    Here is my response:

    " Hi John ... some thoughts:

    1. Climate change, as defined by the IPCC, refers to a change in the statistics of weather over 30-50 years and longer.

    2. Looking for a signal of climate change in short-term weather does not make much scientific sense. It is like looking at one (or a few) hands of poker and asking if the deck is stacked. The answer to your question is thus not yes or no, but rather, it is the wrong question.

    3. We can however look at long-term records of extreme events and ask the question, is there evidence to support claims that extreme events are getting more frequent or intense? With respect to tropical cyclones (hurricanes), tornadoes, winter storms, drought and floods the answer to this question, on climate time scales is no, based on the evidence availble (in some cases substantial, in others less so). There is however evidence for increasing heat waves and in some measures, increasing precipitation (although be careful, not floods).

    I covered this in my recent Congressional testimony, but there is no need to take my word for it as this is the view expressed in IPCC SREX (2012) and AR5 (2013)

    And to be absolutely clear -- human-caused climate change is real, poses risks and we should take action in terms of both mitigation and adaptation. Extreme events are a bad place to look for climate signals and a losing approach to organizing around for advocacy for action.

    Please follow up if any of the above is unclear or if you have follow up Qs.

    Many thanks from Bonn,


  8. Oh yeah, John Vidal is the Environment Editor for The Guardian (UK).

  9. "Climate change is real and is happening now" is a bit of a lame statement. Surely climate has changed as long as the Earth has had a climate. "Human-caused climate change is real." Really? So says the consensus that gave us the statistically insignificant Hockey Stick, failing climate models, and climate policy inflicted energy poverty.