What does a climate disaster look like?

The recent wave of extreme heat-waves and drought over much of the U.S. has rekindled the public’s interest in and acceptance of climate change. The inevitable question that always gets asked is “is this caused by climate change” and the resulting answer is never as simple as the yes-no answer people want. Reality, of course, is more complex.

People wanting action on climate change are, understandably, thrilled about the recent change in public perceptions and are quickly trying to figure out how to best make use of this shift. This is to be expected and anyone concerned about climate change should hope that the current extreme weather provides the necessary push needed to get policymakers to (finally!) act on climate change.

But while we might hope that the current heat is enough to push through effective climate legislation, we shouldn’t expect it to. The heat-wave and drought will at some point come to an end and eventually many areas currently experiencing sweltering heat will be hit with a cold spell. It is only a matter of time.

If people’s acceptance of climate change depends mostly on whether or not it has been hot lately then as the temperature inevitably cools their acceptance of climate change will crumble. Polls are much like weather and climate; there are short-term fluctuations over-top of long-term trends. It is a shame many wanting action on climate change fail to see this.

The problem, as I see it, is that despite the fact that there is good evidence that the increase in extreme weather is related to climate change, it is still weather. The heat-wave and drought currently devastating American corn crops is weather not climate (weather being what is happening outside your window right now and climate being that weather averaged over long periods of time). So what everyone is talking about is not a climate disaster but rather a weather disaster.

This will get your attention

Sun baked fish heads are media darlings

Even dirt can get your attention

Weather disasters are obvious, they make great headlines and thus get plenty of media coverage. Conversely climate disasters are not obvious, despite being devastating. They only become apparent after a careful look at data, they generally don’t make great headlines and most reporters probably don’t have a firm grasp on the issues involved. How much coverage was there of Hansen’s recent 3-sigma manuscript? How many reporters even understand what a 3-sigma deviation is?

This is a climate disaster! Devastating but not exactly headline material on mainstream sites

A better representation of a climate disaster but still not as headline grabbing as extreme weather

This is the problem; reports of extreme weather will continue as long as it is hot out but all this talk of this being a new normal only works to send the wrong message to people.

When someone makes the ‘new normal’ claim I suspect many people expect that now this extreme weather will return every summer. That this is what a normal summer will look like from now on. What happens when we get a cool summer? What happens when we experience colder than normal temperatures? Won’t people start asking “what happened to this new normal?” Won’t people’s acceptance of climate change will decline?

More importantly, would those people be wrong? Of course they would be incorrect to lower their acceptance of climate change because of a spate of cooler than normal temperatures, but would they be wrong to ask what happened to the new normal? I am not so sure. Take a look at the climate disaster bell curves above. The new normal (aka the top portion of the bell curve) has only moved slightly to the right; this is the ‘new normal’ and while it makes heat-waves and droughts more likely, it doesn’t make the current extreme weather normal. It is still extreme, making it normal will take a few more decades of increasing GHG emissions.

And thanks to the decades long lag involved in the climate system by the time the current extremes truly becomes the new normal it will to too late to prevent a disturbingly large degree of suffering.

All of this brings me to my point. We cannot rely on extreme weather to build momentum for action on climate change and by over selling the significance of the current extremes we only make more difficult the deeper understanding we need in order to have an intelligent discussion of this complex problem.

We need to forget the short-term fluctuations in polls measuring people’s acceptance to climate change and instead focus on increasing the slow, long-term acceptance of mainstream climate science. Or to put it another way we need to focus on the climate not the weather.


  1. I completely agree that short term poll fluctuations misread the nature of the climate communication enterprise.

    But intelligent discussion is one thing, and popular support is another. This ties into Schneider's infamous quandary about balancing honesty and impact.

    Much of the press, it's true, will find Hansen's diagrams (which seem to me the most important recent result in climate science by a wide margin) inaccessible. But the fact is that, like it or not, the general public will be even more baffled. You can wave these in front of Inhofe all day and he will just see squiggly lines. (You can wave them in front of Morano and he will just laugh, I figure.)

    So we're still left doing the "weather is not climate, but climate is weather" dance that confuses people about what is evidence, and how much evidence it constitutes. In mass communication contexts this is inevitable.

    We can try to build a more sophisticated audience (that's what P3 is for, after all). We can work toward better informed people on political staffs and in the press. But we can't avoid the fact that the conventional press and the politicians are not addressing that audience directly.

    I took a cab one unseasonably warm day in Chicago a few years back. Cabbies love to talk about weather and climate, I've found, and of course they are keen observers of it, especially in snowy places. So you can get a slice of common opinion sometimes without bringing the subject up. This guy worried about the "polar bears becoming distinct", and I didn't bother trying to explain that he ought to worry about corn crops or the depth of Lake Michigan instead.

    • But intelligent discussion is one thing, and popular support is another

      I don't think I was as clear as I should have been on this point. I don't think that popular opinion needs to be based on a thorough understanding of the problem but it does need to be based on something deeper than recent weather.

  2. Dan, it's money that will drive acceptance of climate change in the U.S. Money in the insurance sense, mainly. The U.S. government has already had to step in to provide flood insurance when the private sector insurers bailed out. Crop insurance anyone? Then there will be the crop losses, flood losses, drought losses. I follow reports on the drought affecting the US south. It's not clear how many more sustained drought years already marginal parts of that region can bear before they become unviable for agriculture, even habitation. Nevada is using state-wide water resources as life support for Las Vegas.

    A friend of my wife's lives outside Phoenix in a spectacular house tht is today worth a fraction of its former value. Water uncertainty is a big factor in the decline in price. People are hanging on because they can't get enough from the sale of their homes to buy something similar in places that aren't water-stressed.

    Once Americans have to face the prospect of internally displaced populations the opposition will fold. Sea level rise is already becoming a concern on America's Atlantic seaboard. Salination of coastal groundwater resources is occuring and will be an increasing problem in Florida where the sponge-like bedrock makes dikes and seawalls totally ineffective.

    Few of us realize it, but British Columbia's Lower Mainland is in a climate change fix. There are large suburban tracts that are below sea level. They're already vulnerable to sea level rise and storm surge impacts that are expected to worsen. Yet the double whammy is the snowpack melt that is being accelerated by warming, triggering flooding. So the region has freshwater threats combined with sea water threats. Add to that the spread inland of brackish water from the Fraser estuary due to sea level rise. Care to throw in a seismic event?

    • I don't disagree, but I think there are a few complications to the insurance story. The main complication is that the insurance market is not really a free market. There are many instances of governments purposely providing insurance when private insurance corporations don't find it economically viable to do so.

      There may be very good reasons for governments to do this but it skews the market response to risk and insulates people from the financial burden of a changing climate.

      Then add the lag inherent in the climate system and by the time the insurance situation becomes dire enough to motivate a policy response to climate change a large amount of suffering will be unavoidable. I hope we can do better

  3. Hi, I have a question about the change in distributions. I understand that increasing the variance is having a large effect on the extremes, but is really shifting the mean a big issue for the extremes?

    Assume (with some made up numbers) that the variance is kept but the mean is shifted 0.5K upwards. Now there seems to be (at least) two ways to look at the changing upper extremes:

    1. We get 5 times more x sigma extreme heat events.

    2. We don't get more extreme heat events, it is just that each event becomes 0.5K warmer, which is hardly noticeable.

    The first sounds alarming but the second not. And the second view points to that any important effect is climate related and not extreme weather related. How can both be true? It seems to me that there is a need to involve some more variables (from physics,biology,agriculture etc.) before drawing any conclusions about the seriousness, only mathematics is not enough.

    • Hmm. I think if sigma is 0.5, shifting by 0.5 is a big deal, while if sigma is much larger than 0.5, moving up by 0.5 will not create an alarming number of high-sigma events (on the old distributions. So I'm not buying your premise.

    • I'm not sure I agree. My point was that what is alarming/bad cannot easily be derived just from pure math and some intuition about what sounds much/little. I wanted to show that by two intuitively different but consistent cases.

      A 0.5 sigma shift means about four times more 3 sigma events.
      But at the same time people may not notice the difference for a single extreme event if it is 0.5 sigma warmer. I call that a paradox.

      However, if the bad effects are threshold dependent, a multiplied number of x sigma events may make a big difference. And of course the biosphere may very well visibly react on a persistent 0.5 sigma shift.

      Anyway, I think Hansen's approach is very striking, using real data and very few assumptions.

      • Sorry, I thought you said 0.5 degrees, not 0.5 sd. (Isn't that what 0.5 K means?)

        Still, while how things are perceived is surely an issue, two equivalent mathematical specifications are equivalent. It's a trivial tautology that it doesn't matter which one you use in a formal argument.

  4. An important caveat here: whether a heat wave is "weather not climate" is a matter of definition.

    Within the field, it turns out there are two definitions of "climate"; climate modelers use the definition implicit in what you argue above - that climate is the statistics of the system and weather is its instantaneous state, or more formally, its trajectory through the statistical universe defined by those statistics.

    Meteorologists, however, use the definition of changes that persist longer than the predictability limits of the weather; this means more than a couple of weeks. Predictions of what the next season will bring are "climate predictions" on this view. I do not regard them as such, but this leads to some very misleading discussions in the press. The people predicting, say, the next hurricane season (including IPCC-loathing Grey and Landsea) are on this definition climatologists.

    The physics behind this longer than a couple of weeks but shorter than a couple of decades range is almost entirely oceanography. These predictions are essentially based on variations in ocean surface temperature.

    And in the ocean, the distinction between weather and climate is not as clear as it is in the atmosphere. The scale separation is not as sharp. There's much more to be said on this topic, but what I wanted to make clear is that your distinction is much more clear in the climate modelers' lexicon (which I tend to use) than in the meteorologists' one.

    But that leaves us in a quandary. When we see seasonally persistent anomalies, do we call that weather or climate? It is weather as long as we think of the ocean as varying through some statistical universe. But the time scale of the anthropogenic forcing (decades) while very long compared to meteorology, is in fact a close match to the time scales of the upper ocean (and fast compared to the deep ocean). Do we call this weather or climate?

    In the meteorological tradition, what is happening now in the central US is a "climate event". In the climatological tradition, there is no such thing as a "climate event"; by definition "events" are weather. Most of the time it doesn't matter much but when you talk about prolonged heat events it can cause confusion.

    None of this takes away from your point, which is obvious from where you live where you have been having quite a chilly year. We have to try to put everything in context.

    But on the other hand, things do appear to be changing rather quickly - note that there is a lag between Hansen's data and the present. We have now had three years of peculiar summer circulation in a row, and the weird austral summer before that. So after three and a half years of very odd large scale circulation, is it really unreasonable to worry that there is a new normal?

    • We have now had three years of peculiar summer circulation in a row, and the weird austral summer before that. So after three and a half years of very odd large scale circulation, is it really unreasonable to worry that there is a new normal?

      Worry? Yes you can (and I do) worry. But I still think it is misleading and could potentially backfire to start calling these extreme summers the new normal. As far as I can tell they still represent an extreme.

      But perhaps the climate has passed a threshold and this is a new normal, in which case we need to ask how many summers will it take until we have enough data to call this normal. Is three enough? I suspect not. What about 5 or 10?

      By all means we can communicate that extreme events are becoming more common because of climate change, we can even (once the have been analysed) begin to say certain events are caused by climate change (as Hansen recently did in his op-ed). But 'normal' means something to the general public; that is the definition (however imprecise) we should stick with

    • I meant to add, that whenever the public's definition of a term differs from that of the scientific community there is potential for confusion. Especially if there are people actively working to confuse.

      The clearest example is the term 'before present' which usually means before 1950 but that is not obvious to the public and that fact has been exploited to mislead and create confusion.

    • So our first response is to prepare ourselves to blame the people warning of the problem? Probably.

      The great thing about climate change is that by the time the plains apes have settled amongst themselves what the new normal is, the normal will have moved again. Lather, rinse, repeat.

      Dan, I wish I could find a conclusion to draw from your views other than that we plains apes are not evolved to deal with this problem. Sadly, I can't.

      Just BTW, have a look at Kloor's thread linking to this one. I've become convinced that it's not the deniers or even the fossil fuel industry that are the core of the problem, although they don't help, rather it's people like Kloor who will endlessly rationalize until such time as they are hit over the head by the proverbial 2x4.

    • So our first response is to prepare ourselves to blame the people warning of the problem?

      I didn't use the word blame for good reason, I am not assigning blame. I certainly don't blame our inaction on people like McKibben (who IMO occasionally goes too far). He has done a great deal to raise awareness, and deserves plenty of kudos.

      But since we seem unable to do anything about the climate problem I think we need to take a hard critical look at why that is. Language like 'new normal' might help in the short term, but long term I think it has the potential to backfire.

      • Ars Technica does not take Dan's advice in reporting on the latest Hansen paper. "Study argues increasingly severe events are the new normal" says the subhead. Of course, this may be another case of disengaged headline writers.

        As for "new normal", our part of Texas is having a more or less ordinary summer, on the hot and dry side but not extraordinary, but not for normal reasons.

        Usually it gets cooler as you head north, and Texas is at the core of the subtropical arid zone in summer. Not this year. This year the subtropical high has moved up to Colorado and Kansas. Central and southern Texas are verging on tropical as opposed to subtropical. The prevailing wind is from the east. Intense rains come and go, moving in random directions. This comes out to fall in our local distribution insofar as temperature and rainfall are concerned, but it's not, in the larger context, a normal season.

        I think it really is starting to hit the fan. Hansen's study confirms one way in which that is clearly the case. "New normal" is sort of wishful thinking. At this point I only wish it were overstatement, but my guess is that it is more likely understatement. "New normal" may be a bit misleading, but it starts to seem unlikely that we will see much of the Holocene climate anymore.

        For myself, I wish Hansen had bucked the pressure to say anything is "because of global warming". We all know what he means but it debases the precision of the language we are trying to use to discuss these matters, more than "new normal" does.

    • What’s unique about the phrase “the new normal”?

      I don't the claim can be supported yet. Even if what we are seeing this year is a new normal it will take sometime before we have data to back up the claim.

      The probability of extreme events has increased (and that should be made abundantly clear to everyone) but that doesn't make the recent extreme heat normal. It is still extreme just less so than it used to be.

    • For the record I think Hansen's loaded dice metaphor is a much better way to communicate what is happening. I particularly like the opening of the Ars Technica article:

      When you see a lot of sixes coming up on a friend’s Monopoly dice, you might begin to harbor a suspicion that the dice are loaded. But if you see sevens appear, you know something is definitely amiss.

  5. Pingback: Shifting norms | Planet3.0

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>