Climate

Must-have PPT: The “global-change-type drought” and the future of extreme weather

This must-have slide (click to enlarge) comes from a 2005 study, “Regional vegetation die-off in response to global-change-type drought.” I first saw it in a powerful 2005 presentation by climatologist Jonathan Overpeck, “Warm climate abrupt change–paleo-perspectives,” that concluded “climate change seldom occurs gradually.”

Overpeck noted that the 2005 study, together with the recent evidence that temperature [in red] and annual precipitation [in blue] are headed in opposite directions in the U.S. Southwest, raises the question of whether we are at the “dawn of the super-interglacial drought.”

Before explaining why I like this slide and how it shows the future of extreme weather, I need to review the conclusion of the study, which was led by the University of Arizona, with Los Alamos National Laboratory and the U.S. Geological Survey:

Global climate change is projected to yield increases in frequency and intensity of drought occurring under warming temperatures, referred to here as global-change-type drought….

Our results are notable in documenting rapid, regional-scale mortality of a dominant tree species in response to subcontinental drought accompanied by anomalously high temperatures.

The researchers examined a huge three-million acre die-off of vegetation in 2002-2003 “in response to drought and associated bark beetle infestations” in the Four Corners area (Arizona, New Mexico, Colorado, and Utah).

This drought was not quite as dry as the one in that region in the 1950s, but it was much warmer, hence it was a global-warming-type drought. The recent drought had “nearly complete tree mortality across many size and age classes” whereas “most of the patchy mortality in the 1950s was associated with trees [greater than] 100 years old.”

The study concluded:

Our results quantify a trigger leading to rapid, drought-induced die-off of overstory woody plants at subcontinental scale and highlight the potential for such die-off to be more severe and extensive for future global-change-type drought under warmer conditions….

It should be obvious that warm-weather droughts are worse than cooler-weather droughts — but if it weren’t, this study shows they are.

The slide depicts annual precipitation and annual temperature in the Four Corners area (i.e. the heart of the U.S. Southwest). It shows that over at least the past 70 years, and presumably much longer, annual precipitation and annual temperature are not particularly correlated. You can have warm droughts and you can have cool droughts.

The warning of the slide to humanity is clear: All future droughts are going to be warm-weather droughts — and if we don’t change course soon — they will become hot weather droughts, then hellish droughts.

Remember, on our current emissions path, the planet is poised to be 5.5°C to 7°C warmer by 2100. The climate models predict that in mid-latitudes land masses (i.e. inland U.S), warming could be 50% higher. That would be 8°C to 10°C warmer — which is way, way off that chart.

And even the Bush administration acknowledged the scientific literature says that on our current emissions path, the SW is poised to get much drier (see “US Geological Survey stunner: SW faces “permanent drying” by 2050“). And that drought will likely last a long, long time (see NOAA stunner: Climate change “largely irreversible for 1000 years,” with permanent Dust Bowls in Southwest and around the globe).

So we have what Overpeck calls “the super-interglacial drought.” Australia, which is more sensitive to initial climate change than the SW and thus a canary in the coal mine, calls it the “permanent dry” or perhaps “collapse.”

Others might just call it a desert.

But before you get the permanent desertification, you get warm-weather droughts, the “global-change-type drought,” and that is the future of extreme weather this century.

Note: I started this new feature and a new category here for Must-have PowerPoint Slides last August (see “Must have PPT #1: The narrow temperature window that gave us modern human civilization“). I haven’t done a good job so far of building out the full set of PPTs, but I will endeavor to add a couple of month.

19 Responses to Must-have PPT: The “global-change-type drought” and the future of extreme weather

  1. paulm says:

    Just in…good luck you all.

    Global temperatures ‘will rise 6C this century
    Surging global greenhouse gas emissions mean the world now faces likely temperature rises of up to 5-6C this century
    http://www.timesonline.co.uk/tol/news/environment/article5882341.ece

    “We can forget about the 2C”,” said Richardson in an interview. “We are now facing the situation where we have to avoid a 5-6C rise in temperature.”

    her comments were based on sifting through hundreds of science research papers submitted to the congress.

  2. MarkO says:

    And so it begins. Umm, again…

  3. Steve Bloom says:

    Most of that is Republicans and/or geezers, DB. Not quite the demographic I’d want to try basing a long-term political strategy on, but good luck trying.

  4. paulm says:

    AGW happens despite what polls say.

    Any polls of knowledgeable and front line scientists?

  5. paulm says:

    Reasona why the public is confused…dithering scientist, mischievous politicians, leaders and rich cooperations….

    Top scientist: don’t trust politicians on climate change
    Politicians were willfully ignoring and misunderstanding the science of global warming, a government adviser said today.
    http://www.timesonline.co.uk/ tol/ news/ environment/ article5880865.ece

    said that the truth could be lost to political expediency or mischief and urged scientists to couch their conclusions in terms that could not be misunderstood or go unheard.

  6. Sasparilla says:

    Nice article, the spread of the jaws in the PPT for the last decade there is very easy to understand.

    Regarding the comments on the expected rise in temps being 5-6C, this is why we better fix things, otherwise we’ll cross those tipping points and its game over.

    Something Joe said in an earlier article, but that gave me some hope, is that counting on the climate legislation from the US government to fix things isn’t reasonable – they won’t give us what we need (coal black dems are a big problem). What we do need can be done by Obama without going through the congress, using controls at his disposal. There’s still hope.

  7. DB says:

    “Most of that is Republicans and/or geezers, DB. Not quite the demographic I’d want to try basing a long-term political strategy on, but good luck trying.”

    No, I’m not trying, but these things are significant in a republic, particularly when time is of the essence. The regulatory route may be the way to go, but with 13,000 point sources that’s a bit messy.

    Joe has written before about generating a WW2 mentality in order to do something of a truly global scale. The Gallup result indicate that we’re not there and, if anything, the movement has been in the opposite direction over the last year.

  8. Steve Bloom says:

    It doesn’t mean much at the end of a winter that was perceived as exceptionally cold in the U.S., noting also that the wingnuts have been engaging in a serious push to shore up their base on this issue since the election. I would agree, though, that not enough of the population is yet on board with strong action.

  9. Bob Wallace says:

    “Results for the latest annual Gallup Poll”

    I wonder why the shift?

    Could it be that people, especially older people, are now so concerned about the economy that they have pushed climate change out of the forefront?

    Perhaps people worry more about a problem that could greatly destroy their way of life in the next few months as opposed to a problem that could come into play decades from now.

    Older people, in general, have much more to worry about when faced with the disappearance of their retirement accounts vs. increases in sea levels that won’t become critical until long after they are dead.

    Don’t forget “Americans generally believe global warming is real.” from the Gallup report.

    Americans have not become deniers.

    Perhaps they are simply prioritizing.

  10. PaulK says:

    “Results for the latest annual Gallup Poll”

    I wonder why the shift?

    Perhaps the catastrophic 7C argument is just not persuasive. For one thing, it is as far outside the most likely IPCC projections as is no warming at all. Secondly, while temperatures may indeed rise to disastrous levels by century’s end, they are not now convincingly moving in that direction.

    [JR: Perhaps the media hasn’t told anybody about this “argument” so they can’t be persuaded.]

    Climate scientists now say we could have an up to thirty year “hiccup” of stable temperatures before warming aggressively resumes. What does that do to the calculus of persuasion?

    [JR: Uhh, no, they don’t say that. Try again.]

  11. paulm says:

    Its going to be a close call (if you believe that we haven’t already tipped the point) because the consensus just isnt there yet in the US.

    Climate change: ‘Obama has to do it step by step’
    Rajendra Pachauri, head of the Intergovernmental Panel on Climate Change, tells David Adam about the USA’s ability to meet environmental targets quickly
    http://www.guardian.co.uk/environment/audio/2009/mar/11/copenhagen-ipcc

  12. Harrier says:

    Well, at least the article mentioned that China would be a country hard-hit by rising sea levels. Maybe that will convince the Chinese to start thinking about reducing their GHG emissions.

    We should still strive to keep warming at or below 2C, even if that’s no longer realistic. Any relaxation of the temperature goal could lead to a relaxation in the efforts to reduce emissions. As it stands, we should work towards zero emissions in all haste, and then deal with the results of whatever warming happens as they come.

  13. Mike D says:

    It actually a pretty warm winter out west, but that’s East Coast bias for ya…

  14. Marie says:

    “urged scientists to couch their conclusions in terms that could not be misunderstood or go unheard…”

    As a non-scientist who reads this blog and urges others to read it, would you please consider adding Fahrenheit temps wherever you reference Celsius? The message is not getting through without this and it is a simple thing to add. I’ll bet 99% of us think and communicate in terms of degrees Fahrenheit in the U.S.

    Also, why call it an “interglacial drought?” Aren’t the glaciers going away in this process, disrupting the balancing systems that “inter-glacial” suggests?

    Thanks for helping us non-scientists who are trying to get and communicate the risks to others. More public policy cost-benefit modeling is needed, to illustrate the implications of the sort of data you share on this blog.

  15. David B. Benson says:

    Marie — degrees Celcius change to degrees Farenheit change: multiply by (9/5).

    Interglacail drought because during stades (massive ice sheets) many parts of the globe experienced severe droughts. I’ll agree it is an unnecessary distinction in this setting.

  16. Gail says:

    Marie’s point is on topic. Most Americans glaze over when it comes to translating degrees Celsius to Fahrenheit. Like it or not, if the issue is how to bring the general population to understand the gravity of global warming, making the science accessible to average Americans who still think in terms of feet and miles, not meters and kilometers, would be a good idea.

  17. PaulK says:

    [JR: Perhaps the media hasn’t told anybody about this “argument” ( a better word is message) so they can’t be persuaded.]

    Something is wrong with the message when almost half think it is exaggerated. Your goal really isn’t to get agreement on any particular climate scenario: it is to eliminate the use of fossil fuel to reduce CO2 levels. Insisting on agreement on the worst case projections is, according to the poll, unproductive.

    Blaming the media went out with the John Birch Society. Climate Progress is part of the media. Al Gore heads a media corporation. NBC, airer of Global Warming Week, is the major media. Robert Kennedy Jr. is part of the media.

    I read a three or four paragraph story a week or so ago in either the Sun Times or the Trib. It quoted two university climatologists who used the term hiccup to describe a possible decadal temperature stabilization. The newspaper used the word cooling. They also said the current cooling – again the word used in the story, could be a misquote – is unexplainable. If you know more about this than what was in the paper, I’d enjoy hearing about it. In fact, when I read it, my first thought was, “Boy, I’ll bet Joe will rip this to shreds.”

  18. Shannon says:

    I think were making the temperature changes worse larger extremes but we only been keeping records in the hundreds of years. There are always extremes. I want to leave the planet better for my children.