‘Global Warming’ to Drought Links Shot Down

Now there’s one less ‘dirty weather’ claim for the bloviator in chief, Al Gore.

A new paper just published and available for preview for the upcoming issue of Nature demonstrates that hyped claims that drought has increased aren’t founded in science. Plotting the Palmer Drought Severity Index globally over the past 60 years they show little change in drought.

a, PDSI_Th (blue line) and PDSI_PM (red line). b, Area in drought (PDSI <−3.0) for the PDSI_Th (blue line) and PDSI_PM (red line). The shading represents the range derived from uncertainties in precipitation.

Here’s the abstract:

Drought is expected to increase in frequency and severity in the future as a result of climate change, mainly as a consequence of decreases in regional precipitation but also because of increasing evaporation driven by global warming. Previous assessments of historic changes in drought over the late twentieth and early twenty-first centuries indicate that this may already be happening globally. In particular, calculations of the Palmer Drought Severity Index (PDSI) show a decrease in moisture globally since the 1970s with a commensurate increase in the area in drought that is attributed, in part, to global warming. The simplicity of the PDSI, which is calculated from a simple water-balance model forced by monthly precipitation and temperature data, makes it an attractive tool in large-scale drought assessments, but may give biased results in the context of climate change. Here we show that the previously reported increase in global drought is overestimated because the PDSI uses a simplified model of potential evaporation7 that responds only to changes in temperature and thus responds incorrectly to global warming in recent decades. More realistic calculations, based on the underlying physical principles8 that take into account changes in available energy, humidity and wind speed, suggest that there has been little change in drought over the past 60 years.

Hmmm where have we seen this before?

NASA’s James Hansen is just wrong: Proof that there is no increased drought in the USA tied to temperature

And here is another:

Hoerling et al. in Journal of Climate: Is a Transition to Semi-Permanent Drought Conditions Imminent in the U.S. Great Plains?

“We conclude that projections of acute and chronic PDSI decline in the 21st Century are likely an exaggerated indicator for future Great Plains drought severity.”

Abstract:

How Great Plains climate will respond under global warming continues to be a key unresolved question. There has been, for instance, considerable speculation that the Great Plains is embarking upon a period of increasing drought frequency and intensity that will lead to a semi-permanent Dust Bowl in coming decades. This view draws on a single line of inference of how climate change may affect surface water balance based on sensitivity of the Palmer Drought Severity Index (PDSI). A different view foresees a more modest climate change impact on Great Plains surface moisture balances. This draws on direct lines of analysis using land surface models to predict runoff and soil moisture, the results of which do not reveal an ominous fate for the Great Plains. Our study presents a parallel diagnosis of projected changes in drought as inferred from PDSI and soil moisture indicators in order to understand causes for such a disparity, and to shed light on the uncertainties. PDSI is shown to be an excellent proxy indicator for Great Plains soil moisture in the 20th Century; however, its suitability breaks down in the 21st Century with the PDSI severely overstating surface water imbalances and implied agricultural stresses. Several lines of evidence and physical considerations indicate that simplifying assumptions regarding temperature effects on water balances especially concerning evapotranspiration in Palmer’s formulation compromise its suitability as drought indicator in a warming climate. We conclude that projections of acute and chronic PDSI decline in the 21st Century are likely an exaggerated indicator for future Great Plains drought severity.

Corresponding author address: M. Hoerling, NOAA/Earth System Research Laboratory

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35 thoughts on “‘Global Warming’ to Drought Links Shot Down

  1. Bullshit.

    Look at the curves, they are completely unbelievable. We know precisely what rainfall and areas in drought conditions were in the 1950s and 1960s, but we have only a crude idea with huge uncertainties what they were in the 2000s? Puh-leeze.

    Wake me when somebody produces a curve with the error bars running from large to small the other way.

    rgb

  2. May be this will be helpful: Climate change had political, human impact on ancient Maya.
    The role of climate change in the development and demise of classic Maya civilization, ranging from AD 300 to 1000, has been controversial for decades because of a lack of well-dated climate and archaeological evidence. But an international team of archaeologists and earth science researchers has compiled a precisely dated, high-resolution climate record of 2,000 years that shows how Maya political systems developed and disintegrated in response to climate change.

    Read the full story on Live: http://live.psu.edu/story/62503#nw4

  3. POI, the UKs annual average rainfall, recorded for over 150 years by The Wet Office & its predecessors, shows no change despite the apparent “unprecedented” Global Warming over the same period! Data, it’s a real pain in the arse at times! :-)

  4. Again nothing new. The Great Plains drought cycle is just part of the middle latitude drought cycle that is directly related to the 22 year sunspot cycle. A.E. Douglass identified this pattern from tree ring studies decades ago.

    http://en.wikipedia.org/wiki/A._E._Douglass

    I found similar patterns in the weather records of the Hudson’s Bay Company and risked failing my doctoral defence (1981) by insisting on leaving in a section on the 22 – year drought pattern identified by spectral analysis and speculation of a the sunspot connection. I gave a paper on the subject at the conference on the eruption and impact of Tambora, which was published in proceedings:
    “Climatic Change, Droughts and Their Social Impact: Central Canada, 1811-20, a classic example.” In C.R.Harington (ed) The Year Without a Summer? World Climate in 1816. 1992, National Museum of Natural Sciences, Canadian Museum of Nature, Ottawa.

    Relationship between sun and temperature was and remains anathema, but the idea it could be related to precipitation was almost completely unacceptable. Of course, it is logical now we know the Svensmark established connection between sunspots, cosmic radiation and low cloud cover. Theodor Landscheidt, with who I corresponded, found a similar pattern in his work.

    http://www.john-daly.com/solar/US-drought.htm

    In a more practical and empirical context, as Chair of the Assiniboine River Management Advisory Board and member of the Manitoba Water Commission I dealt directly with the implications of the pattern of drought on flooding (the Assibinoine is a tributary of the Red River of the north), water supply, agriculture and forestry. I also worked with farmers and agricultural communities in Minnesota and North Dakota as they swung between the wet and dry cycles. I recall giving a presentation in Hallock, Minnesota in 1989 when they were in a serious drought and telling them that flooding, especially at nearby Devils Lake, would become a serious flood problem within ten years.

    I wish these researchers, including the IPCC, would pay heed to what is already in the literature. As I have said many times, the IPCC has set climate research back 30 years.

    http://drtimball.com/2011/corruption-of-climate-science-has-created-30-lost-years/

    and

    http://drtimball.com/2011/weather-and-climate-data-water-the-ignored-variable/

  5. It’s not just the Dirty Drought get shot down.

    “New paper finds the highest storm activity is associated with cold periods”

    http://hockeyschtick.blogspot.co.uk/2012/03/simple-disproof-of-runaway-greenhouse.html

    “We find that high storm activity occurred periodically with a frequency of about 1,500 years, closely related to cold and windy periods diagnosed earlier”

    http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo1619.html#ref1

    “U.S. tornado activity near low point in modern record”
    (non peer reviewed / gray literature:)

    http://www.washingtonpost.com/blogs/capital-weather-gang/post/about-face-tornado-activity-near-low-point-in-modern-record/2012/11/14/9ee31a2a-2e86-11e2-89d4-040c9330702a_blog.html

  6. Now such uncomfortable facts getting in the way of a useful political hypothesis would certainly explain why the Club of Rome is pushing to shut down education that emphasizes binary logic in favor of approaches that push feelings and intuition.

    Emotionally driven mindless drones would never refute former Vice Presidents or heads of federal agencies with inconvenient facts like temps or actual rainfall amounts.

    Someone is just not on board with the philosophy of Theory in Action. Implement the theory in public policy so it can have the desired effect on people and economies.

  7. “…decreases in regional precipitation but also because of increasing evaporation driven by global warming. ”
    What goes up, stays up. Yup, the clouds will increase and the ground will be dry until the seas and lakes have all gone.
    However here in the UK all it does is precipitate water, day after day after day. We could export it and make a tidy profit – where are all those entrepreneurs?

  8. So were there droughts or not between 2000 and 2011? The uncertainty range is so high one could conclude anything. Which pretty much sums up Warmists data.

  9. rgbatduke;
    Wake me when somebody produces a curve with the error bars running from large to small the other way.
    >>>>>>>>>>>>>>>>

    The paper is behind a paywall, so can’t see if they have any explanation for this, but my recollection is that the world went from 7,000 weather stations down to 1,000 in about the time frame that the error bars start to increase on those graphs.

    I’m assuming also that they used weather station data from end to end rather than appending satellite data to the weather station records. Would be of interest to compare the two for the latter part of the record, doesn’t sound like they did.

  10. rgbatduke says: ” [bad word]
    Look at the curves, they are completely unbelievable. We know precisely what rainfall and areas in drought conditions were in the 1950s and 1960s, but we have only a crude idea with huge uncertainties what they were in the 2000s? ”

    Yea, the modern data is that bad, it has been stepped on so many times you would not recognize it. The lid from the rain gauge looks like some kid used it for a hockey puck and the basketball hoop on the stevenson screen tore of half the slats. We reallly do not know what the temperature has been fro the last 35 years. No kidding, 35 years of bad data.
    Wake up.

  11. If claims that global warming causes more droughts are 180° wrong, then if temperatures cool and we get more droughts there are still those who will say they were right all along.

  12. Thanks, David, but that doesn’t make the result any more believable, it merely reinforces the notion that it is unbelievable. They might as well just have published “we have no idea what global drought or the lack thereof are doing now because our current data suck.”

    The other problem is that distributing only 7000 stations around the surface area of the Earth is already a bit absurd, but given any sort of reduction from this already too small number — a number so small that the error bars on the left are still suspect — they should have done one of two things:

    a) Used only the 1000 sites that provided a continuous record, so that the error bars were apples to apples (and the location results ditto);

    b) Found other sources of data that either covered the entire interval or supplemented the “official” sources. If you look at e.g. the network of Weather Underground weather stations, it has an incredibly fine granularity across the US. Even though these are “amateur” sites and many of them have siting problems, it is pretty simple to use statistical techniques that reject embedded outliers and get an amazingly detailed coverage of at least the bulk of the US, no matter how many “official” sites — that have their own issues with outliers and siting — have disappeared.

    What the did instead is still bullshit and useless as the error bars come down to “we don’t know” in spades.

    Dear Andrew30,

    I had my coffee this morning and am adequately awake. Awake enough to rely on things like UAH LTT for my perception of things like global temperature over the last 33 years, not weather stations, so although I appreciate your eagerness to stomp on the reliability of weather stations contributing to e.g. GISS, Anthony has already done an admirable (and quantitative) job of that beyond that I, like Honey Badger, just don’t care.

    I also do not think it is even vaguely conceivable that the uncertainty in the weather data from all sources over the last decade could systematically increase relative to the sixties unless the work was stupidly done. That is why I started my reply with the terse term “Bullshit”. Are you suggesting that I’m incorrect, that the result presented is meaningful? Or are you trying to suggest that I should have written bullshit-SQUARED?

    To be frank, misrepresentation of errors (that is, error estimates that anybody that isn’t a complete idiot can see at a glance are wrong) is a horrendous problem in climate science, starting with Mann’s hockey stick and on. Always the curves, never the curves with error bars that systematically grow into the past to reflect poorer instrumentation and siting (yes, even poorer than now, count on it) and indifferent data collection plus the enormous method uncertainties of things like dendroclimatology where tree-ring thicknesses are somehow used at one and the same time to measure drought and temperature, when in fact one cannot tell if smaller rings reflect drought, temperature, other stresses, combinations of the above.

    I understand perfectly well why this is never done — if it were done, we’d all see at a glance that the correct answer to nearly any question concerning the climate more than 100 years ago is “we have no friggin’ idea”. Antarctica? No friggin’ idea. Most of the Arctic, most of Siberia and China? No friggin’ idea. The Australian outback? No friggin’ idea. Either the SST or temperature profile at depth of the ocean? No friggin’ idea. The climate of the Amazon, or most of central Africa? No friggin’ idea.

    By that I mean that an honest appraisal of uncertainties would result in error bars that are larger than the entire supposed difference in global temperature from (say) the mid-19th century to the present. From the predominant trend in the data we might conclude that it is reasonably certain that the world has warmed since then, but we couldn’t pin down the actual warming within a factor of two.

    rgb

  13. rgbatduke;

    I think that you misread the [bad word] graph; the error bars are the white part, the scratchy bits on the right hand side are just caused by the nervous trepidation of the [really bad word] artist

  14. I’d like to know the justification for why the error bars are broader in recent years than in the past.

    Also, if you include the 1930’s dustbowl in the period, it should be fairly obvious that droughts have probably *decreased* over time. Nothign like a cherry picked time period so they don’t disturb the climate journal compliance officers.

  15. Ok, I’m confused. Others have pointed it out, but I’ll phrase it as a question:

    Why are the error bars in the graph greater more recently? I would have expected there to be more uncertainty for the earlier values, and increased confidence in more recent figures.

    As usual, I expect I’m missing something. Can anyone enlighten me?

  16. Heh. The colder it is, the more dust you have in the atmosphere. Up to thirty times more when it gets really cold.

    That is, in a cold climate it gets dry & windy, in a warm one it is the other way around. It is a well known fact, supported by ample evidence. I don’t even understand how one can get a grant to rediscover lukewarm water. Much less how it was published. Even much less how previous claims of increased drought in a warm epoch, rebutted by the current study, but counterfactual from the beginning, got past peer review at all. What kind of peers one needs to accomplish such a deed?

  17. You can actually click through to the first page of the paper (actually all three pages, but the others are scrambled). Go to the bottom, and click on the picture under “Readcube Access.” This comes with restrictions on printing and sharing. It looks like once you’ve gotten the first page once, you can’t get it again, so be careful about closing the window. After that, you can “rent” it for $2.99, or “buy” it for $5.99. Presumably, that’s for the whole article, presumably, still with restrictions.

    The red-and-blue graph is on the first page. The caption, more detailed than in the preview, says in part, “Uncertainty in precipitation is estimated by forcing the PDSI_Th and PDSI_PM by four alternative global precipitation data sets. Uncertainty from net radiation is estimated by forcing the PDSI_PM with a hybrid empirical-satellite data set [31] and an empirical estimate.” So, for precipitation, perhaps the four datasets diverged recently, or perhaps they have different starting years. For net radiation, the satellite records only go back so far, before which time they can’t be used to estimate uncertainty. One would hope that they discuss this further in the text; for $3 you could find out.

  18. Global cooling expands mid latitude and semi tropical deserts. Warming shrinks them. Look at the Sahara.

  19. rgbatduke,

    You are assuming that the lighter colored areas around the line in more recent times is a depiction of error bars. Without access to the paper this is an unsupported assumption.

    Another interpretation of this is that they only have smothed data prior to 1960 and post 1960 they are showing both the smothed data plus the full range of volitility in the raw observations.

  20. JazzyT;
    One would hope that they discuss this further in the text; for $3 you could find out.
    >>>>>>>>>>>>>>>

    Yeah, well, if I spent $3 every time I was trying to figure out where some result in some climate paper actually came from, I’d be bankrupt.

    rgbatduke is, at day’s end, correct. 1,000 stations isn’t enough and neither is 7,000. But itz worse than that. Even if all 7,000 stations were still around, what would we get from the data? The technologies vary widely, siting standards are all over the map. Worse, over the course of their history, any given station might have changed from one location to another (and several times at that), and had different operators with different procedures (time of observation, etc).

    They couldn’t calculate a proper error range even if they wanted to!

  21. rgbatduke says:
    November 16, 2012 at 9:25 am

    Thanks, David, but that doesn’t make the result any more believable….
    _______________________________
    You echo my thoughts. The error bars make most of the “Run in Circles Scream and Shout” response to the various data laughable if they were not reaching for my wallet at the same time.

    Of course good ole’ Al can be relied on to add a couple zeros to make everything even more ludicrous. (I wonder if he used the step ladder again this time)

    About the only data I have seen down played is TSI, the solar energy curve which keeps getting flattened. First Lean and Fröhlich stomp on it and then Svalgaard.

  22. “calculations of the Palmer Drought Severity Index (PDSI) show a decrease in moisture globally since the 1970s “
    Someone please explain this to me. I thought water vapor had increased. If the decrease is the case, it could be one reason for no warming in 16 years, as water vapor is a many times better GHG than carbon dioxide. Does anyone have quantitative data and calculations?

  23. “Unusually high amounts of rainfall favored an increase in food production and an explosion in the population between AD 450 and 660,” said Douglas Kennett, lead author and professor of anthropology at Penn State. “This led to the proliferation of cities like Tikal, Copan and Caracol across the Maya lowlands. The new climate data show that this salubrious period was followed by a general drying trend lasting four centuries
    ==========
    Must have been those Mayan SUV’s changing the climate. Didn’t the Noble Scientists at State Penn already prove climate didn’t change for thousands of years before humans invented CO2? The Mayan’s must have died out because they invented the hockey stick.

  24. Thank you fred berple November 16, 2012 at 11:36 pm
    Uncyclopedia the content free encyclopedia. Wonderful. LOL INDEED. I still am.
    That’s one web site I’ll visit often.

  25. rgbatduke says:

    Always the curves, never the curves with error bars that systematically grow into the past to reflect poorer instrumentation and siting (yes, even poorer than now, count on it)

    Anthony could use that argument in his 2012 Draft Paper, which has been objected to by a denizen of SkS on the grounds that it can’t be known that poor quality stations NOW were poor quality stations THEN.

  26. Surely everybody knows that climate change in the time of the Mayan civilisation was linked to human sacrifice? Have modern climate scientists incorporated that variable into their models?

  27. Not so long ago we were told about more drought in the UK and permanent drought in Australia. The good news is that Warmists were shamed by the wet facts on the ground. The UK had record rain this year and as for Australia they had Biblical floods last year. What did Warmists do?: blame global warming. They have no shame and simply ignore their earlier pronouncements as if no one was looking.

    “Freak storms, flash floods, record rain – and there’s more to come”

    http://www.guardian.co.uk/uk/2012/jul/08/summer-unending-rain

    “‘Biblical’ floods hit Queensland and leave tens of thousands homeless”

    http://www.guardian.co.uk/world/2011/jan/02/queensland-biblical-floods-australia

  28. You are assuming that the lighter colored areas around the line in more recent times is a depiction of error bars. Without access to the paper this is an unsupported assumption.

    Another interpretation of this is that they only have smothed data prior to 1960 and post 1960 they are showing both the smothed data plus the full range of volitility in the raw observations.

    Sure, if you like. I’m just interpreting the caption of the figure above in the most reasonable way.

    But no matter how the light shading is interpreted, it isn’t reasonable that it would be less “uncertainty” in the 60s than today, given improvements in the instrumentation and the enormous amount of money that has been funnelled into climate research in the meantime. The instrumentation today is surely better. It is supported by radar, collected electronically, produced from standardized and tested apparatus that can screw up, I’m sure, but in general is likely to screw up LESS and be recorded MORE CONSISTENTLY than whatever was used in the 50’s. Even if the number of stations decreased from 7000 to 1000, that should do no more than roughly double the statistical uncertainties (square root of N, not N).

    Under no circumstances is this indicative of a believable result. It is a pointless result, that boils down to “using the stations and methods we included in this study, we haven’t the foggiest idea if drought increased or decreased over the period indicated, or if (most likely) it remained about the same”. Which is the null hypothesis in the first place. This study does nothing to change that.

    So I reiterate: a) Bo-ring. b) Probably wrong or based on poor methodology if modern uncertainties are larger than pre-satellite uncertainties from the 50’s.

    rgb

  29. Surely everybody knows that climate change in the time of the Mayan civilisation was linked to human sacrifice? Have modern climate scientists incorporated that variable into their models?

    Modern data correlates it with the fractional population of the Earth consisting of pirates, not human sacrifice. Sorry. Fewer pirates equals more global warming. Ar.

    rgb

  30. Hmmm, during the end of the LIA, the southern Great Plains and southern Rocky Mountains endured 15 or so years of severe drought (1850 – 1865). The mid-1890s were also grim, and apparently less than optimal precipitation during the period from 1450-1550 caused regional depopulation before the arrival of Europeans and European diseases.

    Alas, I have yet to find the PDSI records kept by the Antelope Creek, Rio Grande Pueblo, or Athapaskan (Diné) peoples of the region in order to make an apples-to-apples comparison.

  31. TXRed says:
    November 17, 2012 at 11:33 am
    ….Alas, I have yet to find the PDSI records kept by the Antelope Creek, Rio Grande Pueblo, or Athapaskan (Diné) peoples of the region in order to make an apples-to-apples comparison.
    ___________________________
    You forgot the Tree Rings. Those magical mannian tree rings that can tell us anything and everything about climate.

  32. Basically, this paper is saying the Palmer Drought Severity Index is an old too simplified model that should be updated now that there is more data available to calculate dought conditions more accurately.

    If that is done, there is little change in drought conditions.

    The paper and new release also questions why the PDSI remains in use and is still used by the IPCC for example since this could have been fixed long ago. They say it is a “curiousity” that it is still in use.

    —————-

    This is something that is becoming more common now. Some climate scientists feel more free now to correct the inaccurate vestiges of the science. Not long ago, they would have been drummed out of the field and/or fired for trying to do so.

    Its a good development.

  33. Let me recall that the wet climates are equatorial, and the dry climates are polar. Ask a penquin about drought. Never have seen a forecast that a “cold wet arctic air mass …” and how about those tripical storms…no water in those? Is there any simple obvious observation of common sense left?

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