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Drought Factcheck

March 25, 2020

By Paul Homewood


One of the frequent claims about global warming is that it will lead to more severe droughts. For instance, the WMO were crystal clear in their latest Greenhouse Gas Bulletin:

The last five years have been the hottest ever recorded. The consequences are already making themselves felt in the form of more extreme weather events and associated disasters, from hurricanes to drought to floods to wildfires.

The Heartland Institute’s factcheck addresses this, with a particular focus on the US, for natural reasons as they are a US outfit.



Bullet-Point Summary:

  • The United States is benefiting from fewer and less extreme drought events as the climate modestly warms.
  • In 2017 and 2019, the United States registered its smallest percentage of land area experiencing drought in recorded history.
  • The United States is undergoing its longest period in recorded history with fewer than 40 percent of the country experiencing “very dry” conditions.
  • The U.N. IPCC reports with “high confidence” that precipitation has increased over mid-latitude land areas of the Northern Hemisphere (including the United States) during the past 70 years, while IPCC has “low confidence” about any negative trends globally. (See, p. 191.)

Short Summary: Real-world data show drought in the United States has become less frequent and severe as the climate has modestly warmed. Moreover, the United Nations reports “low confidence” about any negative trends globally. Droughts have always occurred, and they always will, so alarmists cannot claim that any droughts are necessarily caused by global warming. Instead, analysis of global and U.S. drought data show the droughts that have occurred recently are less frequent and severe than the droughts of the past several decades.

For example, the National Oceanic and Atmospheric Administration chart below shows that the United States is undergoing its longest period in recorded history without at least 40 percent of the country experiencing “very dry” conditions. Note also the peaks in drought around 1978, 1954, 1930, and 1900 are much larger than what the U.S. experienced in the 21st century and the late 20th century.

Figure 1: U.S. Wet and Dry Extremes

Figure 1: Percentage of United States experiencing “very wet” (in green) and “very dry” (in yellow) conditions. Source: National Oceanic and Atmospheric


Picking up on the IPCC link, SR15 also stated:




Regional variations can of course occur for all sorts of reasons, particularly multidecadal ocean cycles. Overall though it is abundantly clear that the WMO’s claim has no scientific basis whatsoever.


The case of the US is particularly interesting though. Just look again at the NOAA chart:

Taking national rainfall trends can be misleading, as they may cover up regional variations. However this tool measures the area of the country experiencing either extreme wet or extreme dry conditions. NOAA define “extreme” as:

Climate divisions with a standardized anomaly in the top ten percent (> 90th percentile) of their historical distribution are considered "very warm/wet" and those in the bottom ten percent (< 10th percentile) are classified as "very cold/dry".

It is abundantly clear severe droughts have become much less common in the last two or three decades, when measured this way.

Previous severe episodes stick out, including the 1910s and 1950s, in addition to the better known dustbowl years.

We can get a more exact picture from the regional precipitation trends:


U.S. Climate Regions


Generally speaking, most regions exhibit earlier periods of drought far more severe than anything seen in recent years. The only real exception is the West, which shows little in the way of any trends at all. (Contrary to wildly inaccurate claims about the recent Californian drought).

Interestingly though, earlier droughts don’t always occur at the same time in different regions. For instance, the worst drought in the Northeast occurred in the 1960s, while by far the worst drought in the South was during the 1950s, a time often ignored but arguably as bad as the 1930s.

  1. Broadlands permalink
    March 25, 2020 7:55 pm

    “Droughts have always occurred, and they always will, so alarmists cannot claim that any droughts are necessarily caused by global warming…”

    Back in the 1930s J.B. Kincer of the US Weather Bureau was interviewed: The Weather Bureau has no explanation for the persistency of dry weather in the southwestern plains or its occurrence in the Northeast, where droughts are uncommon. “Droughts,” said Mr. Kincer, “are weather incidents that just happen.”
    Presumably, he was not pestered about climate change and CO2.

  2. MrGrimNasty permalink
    March 25, 2020 8:21 pm

    Hallelujah. Oh no wait. Obviously doesn’t apply to climate models or the complete lack of quality climate data or the fact that most empirical current evidence disproves the doom narrative.

    • Broadlands permalink
      March 25, 2020 9:03 pm

      “It is not a question of whether models are flawed but in which ways are they flawed, and models can still be enormously valuable if their shortcomings are appreciated. As with other sources of information, however, they should never be used alone.”

      Except when ‘global warming’ is being projected as catastrophic and an existential threat. Then the flaws, pit-falls and shortcomings can be adjusted and corrected to make the narrative fit. It’s called climate forcing.

      • Phoenix44 permalink
        March 26, 2020 8:59 am

        At least they are grasping some of the issues with CV modeling. They claim the Imperial model is flawed but that hasn’t been proven yet.

    • Phoenix44 permalink
      March 26, 2020 8:55 am

      There’s nothing wrong with virus models. The problem lies with the assumptions. If you get those right, the models are very accurate. But the assumptions are really hard to get right, and because you start with a very large number (population) and much of the model multiplies that number, you end up with vast ranges in your output caused by relatively small changes in your assumptions. As I e been saying for a while now, that means the UK modelling of CV is useless. Unless you can realistically bound your inputs to produce a narrow range of outputs, there’s no point running the model.

      By contrast, GCMs don’t work, even if you get most of the assumptions right.

  3. March 25, 2020 11:20 pm

    A few years ago they had determined that the wholw of the US Southwest had been pushed into drought by human caused climate change.

  4. March 26, 2020 4:36 am

    Droughts are a regular feature of the Australian climate. I have recently looked at long-term rainfall records at eight locations in inland Eastern Australia and have identified seven major droughts since 1880. The duration and severity of individual droughts varied with location but the “Federation Drought” of approximately 1895-1906 affected all of the inland region of Queensland and New South Wales. There was no evidence of recent droughts being more severe than those of a century ago.

  5. March 26, 2020 7:55 am

    Before Europeans arrived Australia had two seasons, the wet and the dry.

  6. Phoenix44 permalink
    March 26, 2020 8:49 am

    The claim is utter nonsense. The last five years may have been “hottest ever” but by very small amounts. Why would a few tenths of a degree cause a measurable increase in extreme weather, either frequency of events or their severity? It’s just not possible that we can pick out any increase over and above natural variability. Which us why the IPCC says it can’t .

    This is once again non-science masquerading as science.

  7. March 26, 2020 9:31 am

    Bored at home due to the virus?

    BBC: Help needed to rescue UK’s old rainfall records
    By Jonathan Amos
    Science correspondent
    7 hours ago

    The UK has rainfall records dating back 200 years or so, but the vast majority of these are in handwritten form and can’t easily be used to analyse past periods of flooding and drought.

    The Rainfall Rescue Project is seeking volunteers to transfer all the data into online spreadsheets.

    You’re not required to rummage through old bound volumes; the Met Office has already scanned the necessary documents – all 65,000 sheets.

    You simply have to visit a website, read the scribbled rainfall amounts and enter the numbers into a series of boxes.

    • Russ Wood permalink
      March 29, 2020 12:44 pm

      Retailing this to my wife, she raised an alarming concept – “What if a bunch of dedicated ‘warmists’ signed into the site and loaded the spreadsheets with garbage data?” I DO hope that there will be some form of cross-checking!

  8. March 26, 2020 9:43 am

    One of the frequent claims about global warming is that it will lead to more severe droughts.

    But average rainfall figures are usually higher in summer months 🤔

  9. dave permalink
    March 26, 2020 10:23 am

    On extreme events:

    Ryan Maue has updated his Accumulated Cyclone Energy series. The Southern Hemisphere has been well below normal this season:

  10. The Man at the Back permalink
    March 26, 2020 11:02 am

    A Groupon message today offered me a heavily discounted selection of courses I could take to fill my time, while locked down. I larfed loud at –


    An article I saw a few days ago suggested that we don’t do Risk Management any more – Only Precautionary Principle.

    Most of those who visit Paul’s shop know where that has got us in respect to CO2.

  11. Bloke no longer down the pub permalink
    March 26, 2020 11:37 am

    If everyone is following the UK Govt directions to wash your hands frequently for 20sec at a time, and if half of those people leave the tap running while they do so, will the UK announce a water shortage before August?

    • Gerry, England permalink
      March 26, 2020 1:28 pm

      Only the other week the incompetent Environment Agency was predicting water shortages in England by 2025 due to global warming and so we must change our ways. As you might well expect there was no mention of the government’s immigration policy causing our population to soar especially in the driest part of the country – the South East. Or that the recent Liberal government blocked expansion of water storage.

  12. Coeur de Lion permalink
    March 26, 2020 11:39 am

    btw coal three per cent, wind five per cent

  13. Ewing Caldwell. permalink
    March 27, 2020 5:39 am

    The consequences are already making themselves felt in the form of more extreme weather events and associated disasters, from hurricanes to drought to floods to wildfires.

    Oh dear. And here I was happily thinking that hurricanes, typhoons and tropical cyclones were caused by the Solar Wind and the strength of the more extreme ones were modulated by Solar Flares.

    It seems I’m wrong and they’re all caused by CO2.
    Or the authors of that haven’t read the literature:

    P Prikryl, L Nikitima, V Rinsin: Rapid intensification of tropical cyclones in the context of the solar-wind-magnetosphere-ionsphere-atmosphere coupling. Journal of Atmospheric and Solar Terrestrial Physics. 2018.

    Prikryl et al, Tropospheric weather influenced by solar wind through atmospheric vertical coupling downward control . Journal of Atmospheric and Solar-Terrestrial Physics 2017

    Prikryl et al. A link between high-speed solar wind streams and explosive extratropical cyclones. Journal of Atmospheric and Solar-Terrestrial Physics 2016

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