Climate change could revive medieval megadroughts in US Southwest

Study picks apart factors that caused severe, long-lasting droughts and suggests increased risk for future

Earth Institute at Columbia University

About a dozen megadroughts struck the American Southwest during the 9th through the 15th centuries, but then they mysteriously ceased around the year 1600. What caused this clustering of megadroughts — that is, severe droughts that last for decades — and why do they happen at all?

If scientists can understand why megadroughts happened in the past, it can help us better predict whether, how, and where they might happen in the future. A study published today in Science Advances provides the first comprehensive theory for why there were megadroughts in the American Southwest. The authors found that ocean temperature conditions plus high radiative forcing — when Earth absorbs more sunlight than it radiates back into space — play important roles in triggering megadroughts. The study suggests an increasing risk of future megadroughts in the American Southwest due to climate change.

Previously, scientists have studied the individual factors that contribute to megadroughts. In the new study, a team of scientists at Columbia University’s Lamont-Doherty Earth Observatory has looked at how multiple factors from the global climate system work together, and projected that warming climate may bring a new round of megadroughts.

By reconstructing aquatic climate data and sea-surface temperatures from the last 2,000 years, the team found three key factors that led to megadroughts in the American Southwest: radiative forcing, severe and frequent La Niña events — cool tropical Pacific sea surface temperatures that cause changes to global weather events — and warm conditions in the Atlantic. High radiative forcing appears to have dried out the American Southwest, likely due to an increase in solar activity (which would send more radiation toward us) and a decrease in volcanic activity (which would admit more of it) at the time. The resulting increase in heat would lead to greater evaporation. At the same time, warmer than usual Atlantic sea-surface temperatures combined with very strong and frequent La Niñas decreased precipitation in the already dried-out area. Of these three factors, La Niña conditions were estimated to be more than twice as important in causing the megadroughts.

While the Lamont scientists say they were able to pinpoint the causes of megadroughts in a more complete way than has been done before, they say such events will remain difficult for scientists to predict. There are predictions about future trends in temperatures, aridity, and sea surface temperatures, but future El Niño and La Niña activity remains difficult to simulate. Nevertheless, the researchers conclude that human-driven climate change is stacking the deck towards more megadroughts in the future.

“Because you increase the baseline aridity, in the future when you have a big La Niña, or several of them in a row, it could lead to megadroughts in the American West,” explained lead author Nathan Steiger, a Lamont-Doherty Earth Observatory hydroclimatologist.

During the time of the medieval megadroughts, increased radiative forcing was caused by natural climate variability. But today we are experiencing increased dryness in many locations around the globe due to human-made forces. Climate change is setting the stage for an increased possibility of megadroughts in the future through greater aridity, say the researchers.

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From EurekAlert!

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120 thoughts on “Climate change could revive medieval megadroughts in US Southwest

  1. In the context of understanding climate change drivers this is interesting research on a very complicated topic. To ask the bleeding-obvious question, however, as it is clear that the “magic molecule” had pretty much zero influence over these historic climate events, why are the authors so keen to hypothesise that CO2 will drive such changes in future? What evidence do they have for such a giant and fundamental leap of faith?

    • Faith. That’s all they need. CO2 is the only thing they think can change or control climate. So it’s the only thing relevant.

    • “why are the authors so keen to hypothesise that CO2 will drive such changes in future? ”

      physics known for over 100 years.

      • A doubling of CO2 concentration may, according to Arrhenius, in theory lead to a 1.2°C rise in temperature. In the real world, as opposed to the theoretical one observations are calling that theory into question.

        And any warming in excess of that 1.2° relies on the application of a range of hypothetical forcings, feedbacks and other mysterious ingredients for which there is as yet no physical evidence or justification.

        But don’t let such minor matters get in the way of some good policy-based evidence-making.

      • Thanks for giving me such a good laugh on a grim, wet Saturday morning in “climate emergency” Surrey Mr Mosher. The physics is very much more complicated than CO2 being the primary control knob over the climate, as well you know I am sure.

      • You funny man Steven. Hope you got your IRS re:Bitcoin letter. That’s not so funny.
        Death and taxes, the only sure thing.
        Climate change due to the MagicMolecule… not so much.

      • See

        https://www.mercurynews.com/2014/01/25/california-drought-past-dry-periods-have-lasted-more-than-200-years-scientists-say/

        “…Through studies of tree rings, sediment and other natural evidence, researchers have documented multiple droughts in California that lasted 10 or 20 years in a row during the past 1,000 years — compared to the mere three-year duration of the current dry spell. The two most severe megadroughts make the Dust Bowl of the 1930s look tame: a 240-year-long drought that started in 850 and, 50 years after the conclusion of that one, another that stretched at least 180 years.

        “We continue to run California as if the longest drought we are ever going to encounter is about seven years,” said Scott Stine, a professor of geography and mental studies at Cal State East Bay. “We’re living in a dream world.”

        It looks more like the west over the last couple of centuries was unusually wet compared to the last couple of millennia.

        • There *is* a reason why much of the American Southwest is classified as desert and much of inland CA is classified as semi-arid desert.

          Deserts have droughts! Sometimes short, sometimes long.

          Your use of the word “unusually” is appropo!

        • Alan
          I think that you should have put “mental studies” in single quotes. You had me going there for a moment because I’m starting to get used to absurd academic programs.

      • Steven Mosher – July 27, 2019 at 12:33 am

        physics known for over 100 years.

        As usual, you are confusing the application of “fuzzy math” with the hypertheoretical “claims” of a wannabe physicist.

      • Physics knew no such thing. What a blantantly obvious exaggeration and lack of scientific knowledge. It does support “you just gotta have faith” to believe in the magic molecule, however.

      • You put a life size bronze statue of Steven Mosher knee deep in a tub of boiling water with a thermometer in its mouth and physics tells him what will happen to the thermometer. Steven suddenly ditches his simple physics meme when invited to substitute for the bronze statue because he doesn’t trust the Climastrologists telling him it’s OK because they’ve computer modelled the same outcome eventually from first principles. Ringing in Steven’s ears is’ We can’t explain the decline and it’s a travesty for Steven that we can’t.’

      • Climastrologists might have a future in the comic book business after the hoax is over.

      • Mosher
        Why am I NOT surprised by you providing a simplistic answer to a complex question?

        Lord Kelvin infamously said that heavier-than-air craft would never be able to fly. He also was off by orders of magnitude on the age of Earth, based on the thing that he was famously an expert on, thermodynamics. The problem for both of those failed predictions was what he didn’t know.

        Similarly, Arrhenius performed simple laboratory experiments that really only demonstrated that CO2 could absorb IR. What he didn’t have an appreciation for was the myriad forcings that are a part of feedback loops.

        Your bias (and unwarranted arrogance) is showing!

        • CAGW is based upon a flawed understanding of physics, first promulgated by Svante Arrhenius back in 1896, before we even had a firm grasp on particle physics.

          It was before the discovery of the photon, before the discovery of the electron, before the discovery of the proton, before the discovery of the neutron, before the discovery of atomic nuclei, before the Planck blackbody formula, before Special and General Relativity, obviously long before we discovered exactly why atoms and molecules emit at specific spectra, and a full decade before Einstein fully explained the discrepancies up to that date between Equipartition Theorem theory and empirical observation, ushering in a new quantum theory of matter.

          Arrhenius didn’t even know enough about particle physics to call it “CO2”, he called it “carbonic acid”! Further, his experiment failed to account for water vapor, used 9.7 µm radiation (while CO2 absorbs mainly at 14.98352 µm) and he over-estimated the absorption coefficient of CO2 by 253%, forcing him to later revise his estimate (which was still wrong) of temperature forcing from CO2.

          Yet his flawed experiment is still touted by the climate alarmists as their basis for alarm and hence their basis for tearing down our modern society, deindustrialization and depopulation of the planet.

          • LOL@Klimate Katastrophe Kooks

            I was unaware that Arrhenius used the wrong wavelength for CO2.

            I do hope that Mosher reads your excellent response. However, I doubt that he has the intellectual integrity to respond to your points.

      • “why are the authors so keen to hypothesise that CO2 will drive such changes in future? ”

        physics known for over 100 years.

        Didn’t drive it the past. No reason to think it will in the future.
        For crying out loud, get a grip.

      • According to mainstream climate scientism, CO2 is higher now than at any time for millions of years.
        In fact, starting in the late 1800’s, the story goes, CO2 went above the highest levels previously seen in these prior ages.
        So if CO2 is going to, according to physics, force megadroughts to occur in the SW US, we ought to expect to see the period from the late 1800’s until now be an increasingly dry one in tis region, drier than it has been in millions of years, if indeed it is any sort of well known physics that says it must be so.
        But we do not see that pattern.
        At all.
        Instead and in fact, we see pretty much the opposite: This period of time of elevated CO2 has been the wettest period, and the most stably wet period, in over 1000 years!
        Someone doing actual science would conclude that CO2 and or warmth leads to wet and stable conditions in the regions in question.
        El nino periods are known to cause a temporary global warming, and are also associated with wet years in the SW US.
        The hottest period in the US in the past 140 years was the 1930s, and yet people fled dry conditions in the middle of the US and moved en mass to CA, where plenty of rain meant plenty of work for these people.
        And the entire 140 year period marks a warmup from the previous cold of the LIA.
        And this warmup coincides wit the wettest and most stably moist period.
        The 1970s was the coldest period in the US in the past 100+ years, and for several of the coldest years of the 1970s, CA was in a terrible drought. Which was blamed on global cooling at the time.
        The only way to make a case that CO2 and or warming cause drier weather in CA and the SW US in general is to just say it, with zero evidence.
        People who make such baseless assertions are most properly described as cranks.

        • “This period of time of elevated CO2 has been the wettest period, and the most stably wet period, in over 1000 years!”
          ..
          Do you have a citation to the data that shows your assertion?

      • Isn’t it “proven”, and don’t 97% of all scientists (the Kafkaesque definition anyway) agree, that CO2 is a “trailing” indicator of a rise in temperature?

      • BTW…California had a drought busting water year in 2017-2018, which defied predictions and turned out to be the wettest year in the documented history of the state.
        At the time, the ENSO was in the la nina phase, IIRC.
        These guys should really start being scientists and admit it when they do not have enough knowledge or information to be able to say how much rain will fall in any given area…until it actually happens.
        Their predictions are worse than a drunken blindfolded monkey throwing blunt darts.

      • Among the physics known for the last 100 years is the exponential decay of the GHG effect of CO2, recognized by Arrhenius. 50% of its GHG efffect is in the first 20ppm, with exponential decline. We are in the fifth half-life of that decay, so the next doubling, to 800ppm, will increase its GHG effect by less than 2%.

        CO2 at this time at these levels is not a driver unless it has an awful lot of help. It is not in control. And we are not in control of CO2.

      • You mean the particle physics which shows that above ~288 K, CO2 is a net atmospheric coolant?

        What’s the stated average global temperature again? Oh yeah… 288 K.

        ———-
        All radiative emission to space is, by definition, a cooling process. The only way our planet can shed energy is via radiative emission to space.

        N2 and O2, comprising ~99% of the atmosphere, are homonuclear diatomics and therefore have no net magnetic dipole, rendering them unable to effectively emit (or absorb) IR. Thus the only way they can cool is via conduction by contact with a cooler surface, or via transfer of their translational mode energy to the vibrational mode quantum state energy of radiative molecules.
        ———-
        The radiative cooling of air via solely translational mode energy converting to radiation
        CO2{v20(0)} (at 288K+) + CO2{v20(0)} (at 288K+) -> CO2{v20(0)} + C02{v21(1)} -> CO2{v20(0)} + CO2{v20(0)} + 667.4 cm-1

        You’ll note the above interaction is a direct conversion of translational mode energy (which we perceive as temperature) to 14.98352 µm radiation. This directly cools the air, and the effect is significant, since nearly all the translational mode energy is converted to radiation, leaving the CO2 molecules at a very low temperature, whereupon they absorb energy by colliding with other atmospheric constituents. The effect begins taking place significantly at ~288 K, the temperature at which the majority of the molecules will have sufficient translational mode energy to convert to vibrational mode energy.

        288 K also happens to be the stated average global temperature… that is not a coincidence, it is a mechanism long known, partly a result of CO2 radiative emission ramping up at ~288 K. As CO2 concentration increases, this effect will become more pronounced, increasingly damping any temperature excursions above ~288 K by increase of radiative emission via this interaction, and below ~288 K by reduction of radiative emission via this interaction.

        It is not necessary for CO2{v20(0)} to collide with another CO2 molecule for this interaction to take place, any other molecule will do… the Equipartition Theorem dictates that all atmospheric constituents at the same temperature will have the same translational mode energy. So in reality, the above interaction could be represented thusly:
        X (at 288K+) + CO2{v20(0)} (at 288K+) -> X + C02{v21(1)} -> X + CO2{v20(0)} + 667.4 cm-1
        where X is any atmospheric molecule.

        Further, you’ll note that if a CO2 molecule is already in the CO2{v21(1)} vibrational mode quantum state, a collision at just 0.1 K higher temperature (ie: ~288.1 K) can excite it to the CO2{v22(2)} state, whereupon it can emit a 14.97454 µm photon to de-excite to the CO2{v21(1)} state, and a 14.98352 µm photon to de-excite to the CO2{v20(0)} state.

        Even further, you’ll note that if a CO2 molecule is already in the CO2{v22(2)} vibrational mode quantum state, a collision at just 0.1 K higher temperature (ie: ~288.2 K) can excite it to the CO2{v23(3)} state, whereupon it can emit a 14.96782 µm photon to de-excite to the CO2{v22(2)} state, a 14.97454 µm photon to de-excite to the CO2{v21(1)} state, and a 14.98352 µm photon to de-excite to the CO2{v20(0)} state.

        This implies that for temperatures above ~288 K, more of the translational energy of atmospheric molecules will flow to CO2 vibrational mode quantum state energy, rather than vibrational mode quantum state energy of CO2 flowing to translational energy of other atmospheric molecules, simply for the fact that at and above that temperature, the combined translational energy of two colliding molecules is sufficient to excite the CO2 vibrational modes. This increases the time duration of CO2 vibrational mode quantum state excitation and therefore the probability that CO2 will radiatively emit, breaking LTE. Therefore the energy flow is to CO2, not from it.

        In other words, at and above ~288 K, the combined translational mode energy of two molecules is higher than C02{v21(1)} vibrational mode energy, and therefore energy will flow to CO2 from other atmospheric molecules’ translational mode energy during molecular collision, simply because CO2 can radiatively emit that energy and break LTE, rather than that energy flowing back to other molecules.

        You’ll note that’s diametrically opposite to the claimed mechanism by which CO2 purportedly causes global warming. Liberals tend to invert reality, and rely upon the low standard of education to sustain that inversion’s claims.
        ———-
        Satellites see CO2 and (a bit of) water vapor radiating at the temperature of the lower stratosphere (at the ‘characteristic-emission surface’ altitude, or just less than one optical depth from TOA for any given wavelength) all over the planet. This is because ozone (O3, excited by incoming solar radiation) and collisional processes excite nitrogen (N2) to its {v1(1)} (symmetric stretch) vibrational mode, and N2 then transfers energy to the {v3(1)} (asymmetric stretch) mode of CO2 via collision as shown in the image, whereupon the vibrationally excited CO2 partially de-excites by dropping from the {v3(1)} (asymmetric stretch) mode to either the {v1(1)} (symmetric stretch) mode by emitting a 10.4 µm photon, or to the {v20(2)} (bending) mode by emitting a 9.4 µm photon.

        This is the same method by which a CO2 laser works… the laser filling gas within the discharge tube consists of around 10–20% carbon dioxide (CO2), around 10–20% nitrogen (N2), and a few percent hydrogen (H2) and/or xenon (Xe), and the remainder helium (He). Electron impact vibrationally excites the N2 to its first vibrational mode quantum state {v1(1)}, the N2 collides with CO2, the CO2 becomes excited in the asymmetric stretch vibrational mode quantum state {v3(1)}, and de-excites to its {v1(1)} or {v20(2)} vibrational modes by emission of 9.4 µm or 10.4 µm radiation (wavelength dependent upon isotopic composition of the CO2 molecules) as described above. The helium is used to fully de-excite the CO2 to the {v20(0)} ground state after it’s radiatively de-excited to maintain population inversion (which is necessary for stimulated emission), but this is unimportant to the process of energy transfer from vibrationally excited N2 to CO2 in the atmosphere. The process by which the N2 becomes vibrationally excited (in the case of a CO2 laser via electron impact; in the atmosphere via translational-to-vibrational collisional processes and via vibrational-to-vibrational collisional processes with solar-excited O3) is similarly unimportant… the concept of energy flowing from N2 to CO2 is the same. Laser wavelength can be tuned by altering the isotopic ratio of the carbon and oxygen atoms comprising the CO2 molecules in the discharge tube, with heavier isotopes resulting in longer wavelength emission.

        The Boltzmann Factor shows that ~10.26671% of N2 molecules are in the N2{v1(1)} excited state at 288 K due to collisional (t-v) processes. That’s 195 times more excited N2 molecules than all CO2 molecules (vibrationally excited or not).
        ———-

        Yeah… physics known for over 100 years completely and utterly disproves the CAGW hypothesis.

        Physics isn’t your friend, Mosher. LOL

  2. Same old, same old. In the past there were natural factors causing climate change. Since the industrial revolution, nature has stopped working and humans took over. This mindset places a question mark behing the value (if any) of the research and the conclusions.

    • “Same old, same old.”

      It doesn’t really matter if we know for sure why the Western US is potentially subject to prolonged droughts. The evidence that they can and have occurred is pretty strong. It might be a REALLY good idea to divert some of the energy being poured into quite possibly misguided climate change concerns into worrying about water management in Western North America. In point of fact the available water South of the Columbia River is pretty much at least 100% committed in normal years. I’m pretty sure that not one drop of Colorado River water has reached the Gulf of California in decades. The Rio Grande and Sacramento-San Joaquin aren’t much better. Where and what is the plan for dealing with a decade or longer drought in the West?

      • One place to start would be not flushing a years supply to the ocean to supposedly save a few buckets full of minnows, which in all probability need no saving.
        But the fact is you are correct that they have no plan for such as you describe.
        They are preoccupied with the idea that the solution is to grant more money and power to politicians.
        They waste billions on trains few will use.
        They speak inanely about tearing down dams, instead of building new ones.
        In normal years and dry ones, their may not be much if any extra water, but that is the whole point of dams: The amount of excess water in wet years is tremendous. If saved in reservoirs or by some other means, such as recharging aquifers, then I think the excess water in wet years is more than enough to make up for the shortfall in dry years.
        In entire dry decades, it is almost for sure than adjacent regions will be abnormally wet. In fact this pattern is nearly absolute, with the caveat that the adjacent region getting excess rain may be over the ocean.
        In every year where a drought is existing somewhere in the US, some other are is getting excessive rain and flooding. The amount of water that rushes unused into the sea during these times and in these places is incredibly huge: There have been individual flood events in recent years in which excess river flows to the sea are greater than all the water used in the entire US for any purpose.
        Imagine a pipeline system on the scale of the interstate highway system. Imagine it accompanied by man made water retention areas that would become vast lakes in wet years, and diverted water that could minimize flooding.
        It may take a lot of energy to move the water around, but if planned well, much could be done with gravity via the siphon effect, even moving water over mountains and across entire continents.
        Creating lakes large enough to do the job would require land set asides, but these lakes would become recreation and wildlife refuges.
        Another plan would be to make use of Great Lakes water during times when the lakes are high, like it has been in recent years.
        Of course, another possibility is that the hundred plus year earthquake deficit in California will soon come to an end and trigger a large outmigration of people.
        Geologists estimate that as many as 8 destructive earthquakes are well overdue in CA, and that is just along the three fault segments with the largest amount of yearly slip.

  3. “During the time of the medieval megadroughts, increased radiative forcing was caused by natural climate variability.” So what caused the climate variability? The authors cop out on that one. THERE IS NO PROOF OF INCREASED SOLAR ACTIVITY SENDING MASSIVE AMOUNTS OF MORE SOLAR RADIATION TO THE EARTH at any time. There is the natural cycle from 1361 -1366 W/m^2 TOA figures but that is it. The only cycles of significance are the 147 million year ice age cycle and the 113000 yr Milankovitch glacial cycle , but the correlations of these with temperature changes are poor. Even if there were massive increases in solar activity, that doesn’t necessarily lead to droughts. The fact is we don’t know what causes droughts. Until we know what causes droughts, we can’t even to begin to pretend that we understand climate.

    • I have not seen any data for such but I was always curious about the impact of the thermosphere as the solar cycles change in intensity? When the sun is very active it bulks out and heats up to a couple thousand degrees. If this bulking out of the thermosphere happens – is it possible that less surface radiative outgoing radiation makes it through and more is reflected back as downwelling radiation? I realize this is rarified air – but if the thickness bulks out with high solar activity – it might make that few watts per meter difference that causes these dramatic warming pulses.

      It also seems like the jetstream is more often zonal when the solar cycle is high and meandering when low. The meandering Rosby waves might function as a greater heat pump allowing blobs of warm air into the arctic where it dumps heat into the ice which slowly radiates it out. The cooled surfaces that were under the adjoining cool blob might decrease the melting of winter snows — which leads to less surface heating overall because of snow albedo. Over time that might be what leads to warming and cooling variability outside of co2.

      • When solar activity is low, TSI drops, and a higher proportion of the Sun’s output is in the far UV bands.
        It is this UV that is intercepted by the thermosphere and makes it hot, and not just during periods of low solar activity, but all the time. So what is happening is that less of the incoming solar is even making it past the upper layers of the atmosphere.
        So the opposite is true…low solar activity is thought to result in net global cooling.
        Even the warmista organization called NASA believes that the ongoing period of low solar activity and reduced TSI will result in global cooling:
        https://wattsupwiththat.com/2018/09/28/nasa-the-chill-of-solar-minimum-is-being-felt-in-our-atmosphere-cooling-trend-seen/

        At this point, TSI is the lowest ever measured, and appears to still be dropping fast:

        http://woodfortrees.org/plot/pmod

        So, the answer to your question, will low solar activity lead to warming due to thermosphere heating up and impeding outgoing radiation (?): All signs point to no.

    • The only “Milankovich cycle” close to 113,000 years is apsidal precession. Which was in fact not studied by Milankovich. Hard to see that as strong climate driver. In fact it only modulates the period of axial precession between 23,000 and 28,000 years.

      • Eccentricity is around 100,000. But it is not one parameter that matters, it is several parameters lining up together to change the insolation at the Earth’s surface.

    • That was my immediate reaction. How could they conclude that changes in radiative forcing was a contributing factor when they have absolutely no evidence that any such changes took place?

      They might as well conclude that lack of Indian rain dances during that time was a contributing factor.

      • How could they conclude …“?

        1. Megadroughts were caused by natural factors.
        2. In the climate models, CO2 is far more powerful than natural factors.
        3. Therefore CO2 can give us even worse megadroughts.

        The logic is so straightforward that there is no need to know what the natural factors were or how they worked, and there is no need to model them. If you think otherwise, just check the logic. It’s watertight (a completely useless attribute, BTW, because there won’t be any water).

  4. That sounds a reasonable suggestion. The present warm period is likely to continue for another couple of hundred years, if history is a guide – perhaps even a bit longer thanks to increased atmospheric CO2. We should know about year 2200. Watch this space.

    • The human population on earth in 2200 is likely to be around 2 billion, the result not of disease, famine, or climate change, but rather of sustained below-replacement fertility.

      No one will be worried about carbon emissions at the point.

      • Good and valid point. We human beings are not like rats or lemmings (though some of us haven’t got much better brains!)
        And, you are right : people then will look back at our befuddled age and laugh.

      • Certainly the UN’s own projections are that population will stabilise around mid-century and start to decline around 2100.

        Yet again — for the how-many-umpteenth time?— the neo-Malthusians have it wrong. We are perfectly capable of feeding a population of 11 billion (given a bit of determination, honest effort, and technology) and the surest way of limiting population is not by culling or contraception but by alleviating poverty.

        It is amazing how often clever people can identify a potential problem and unerringly choose as a remedy the one thing likely to make the problem worse. I’m thinking of calling it Newminster’s Law and applying for a research grant.

      • I suspect you are right. I doubt if the UN or any other forecasters considered this type of societal response resulting from using technology to reinforce culture:
        “Authorities in a northern India state launched an investigation this week to uncover why no girls were born in 132 villages in three months. The reasons for the skewered sex ratio are widely known but there’s little will to tackle the problem.”
        https://www.france24.com/en/20190724-india-northern-women-sex-ratio-violence-birth-rights

        If you want to reduce the population, getting rid of females is very effective (the number of males does not matter).

  5. During the time of the medieval megadroughts, increased radiative forcing was caused by natural climate variability. But today we are experiencing increased dryness in many locations around the globe due to human-made forces.

    We have been warming out of the Little Ice Age since the mid 1800s. Even the alarmists have to admit that began as natural variability. So, the question is how much of the recent warming is due to natural variability and how much is human caused.

    The reason Dr. Mann tried to wipe out the Medieval Warm Period is that it shows that the warming since the mid 1800s is likely entirely natural. His hockey stick makes it look unnatural and therefore points to a human cause.

    It’s a big problem for the alarmists to say things will return to the way it was before, when it was caused by mother nature, but this time it will be our fault.

    Here’s how the logic works: There have been traffic accidents at the intersection in front of my house. The neighborhood strange lady says that any subsequent accidents will be my fault because I planted roses in my back yard.

    Alarmist logic is witch doctor logic.

    How about: No dragons have devoured maidens in our neighborhood since I started keeping cats. The grateful neighbors should subsidize my vet bills.

    • “We have been warming out of the Little Ice Age since the mid 1800s. Even the alarmists have to admit that began as natural variability.”

      It has recently occurred to me that firewood smoke may have had a far more toxic cloud/smog forming potential than SO2. Cloud/smog reflect sunlight and therefore cause cooling, it’s it looks certain to me the reduction in SO2 after the clean air acts of the 1970s was responsible for the short term “rebound” of temperatures from 1970-2000. As such, there may have been an initial warming (or reduced cooling effect) when coal burning became widespread.

      So, can you put me down as an agnostic on man-made warming from the little ice-age?

    • “commieBob July 26, 2019 at 11:15 pm

      Alarmist logic is witch doctor logic.

      Bingo! Well summarized,

      “commieBob July 26, 2019 at 11:15 pm
      How about: No dragons have devoured maidens in our neighborhood since I started keeping cats. The grateful neighbors should subsidize my vet bills.”

      By what method do you know you have maidens in your neighborhood?

      It is possible that cats distract you during dragon feeding times.

      • I think dragons are afraid of cats the way elephants are afraid of mice. They don’t have to do battle to repel dragons, also, I haven’t noticed any charred hair.

        During my residence here, several girls have been born, grown to adulthood, and left home for post secondary education or marriage. I am sure that at some point the majority of them could have been counted as maidens.

        I don’t know if the cats distract me during dragon feeding times. They are, however, reliably distracting during cat feeding times.

        Usually, if a maiden gets devoured by a dragon, the parents go postal. I’m pretty sure I would have noticed the commotion.

  6. And what happened in the parts of the world where there was history recorded at the time?

    • hush your mouth! it doesnt agree with their theory so it will be ignored..nothing to see here…etc

    • The period in question seems to overlap the MWP and LIA. It would take some work to correlate specific droughts with events in Europe, Africa and Asia. Or maybe there’s no correlation.

      • It seems that it can be dry in CA and the SW US when it is a warm period, and when it is a cool period, and when it is a cool period within a warm period, and when it is a warm period within a cool period.
        And vice versa.
        There is no correlation.

  7. Wait about, this implies that a medieval global warming caused medieval draughts ?

    Medieval global warming. Say that twice indeed.

  8. Because they don’t understand the “why” of the past, they magically pretend they can forecast the future. The only ones they are deceiving are themselves and their cult followers.
    That’s the very definition of Feynman’s Cargo Cult Science.

    And the Left arrogantly likes to smugly think it’s the Conservatives who are anti-science. The intellectuals on the Left are the real idiots; Taleb’s IYI. And they are too stupid to realize it.

    • To be clear:
      The “why” of ENSO eludes us today it terms of predictability, it is pseudorandom phase to phase, and also on longer terms of more dominant El Nino or La Nina periods. No one can say with any certainty what next summer’s June-July-August ENSO 3.4 value will be. We know not the mechanism. To say what the mechanism was 400 years ago for a dominant La Nina cooling period is preposterous. Knowing something happened in the past is far, far different than understanding the “why.”

      And if it unpredictable in the present or past, it is surely “unpredictable” as to any cause-effect state in the future.

      • Several years ago on this forum a geologist advanced a theory that linked plate tectonics ring of fire activity to generate the energy necessary for ENSO development. Unfortunately this website’s search engine can’t resurrect it due to my shortcomings. Does anyone else recall this article? If so please mine it from the archives to have Joel O’Bryan look at it and comment. I don’t think Joel was commenting at the time.

        • Bigfoot: don’t know about the article you reference, but here is a link to a website that may have been the source of the article. The author puts forth a ENSO theory similar to the article you mentioned.
          http://www.plateclimatology.com/ I listed it as a comment on another article hoping to get some commentary but got zilch. I think the theory is interesting, but no one seems to agree.

      • Joel O’\Bryan:

        You said “To say what the mechanism was 400 years ago for a dominant La Nina cooling period is preposterous”

        No, it is not preposterous. This was during the depths of the Little Ice Age, which was caused by increased volcanism, and the cooling from their SO2 aerosol emissions was responsible for the La Ninas of that period.

        Conversely, the warming from 950 to 1600 that is mentioned in the paper spans the Medieval Warm Period, where volcanic activity was greatly diminished, with few SO2 aerosols in the atmosphere to cause any cooling.

        Without exception. all La Ninas are coincident with increased levels of SO2 aerosols in the atmosphere, and all El Ninos are coincident with decreased levels of SO2 aerosols in the atmosphere.

    • Pfft, climate science is easy; past climate change was natural and modern climate change is all man made, so now that we have our conclusions we can start gathering data.

  9. Disappointing to read again of scientific investigation seeking to find disasters, rather than making a study of the usual condition, with the chance of detecting both favourable and favourable unusual conditions.
    It is like the overall case in climate work, where the usual natural condition should have been researched and understood, before hurrying off to name a disaster agent, CO2, whose understanding is severely limited by lack of knowledge of the usual condition. Thus, the difficulty in separating natural from anthropogenic effects. There can be no validation of control knob speculation until we can attribute events/effects to natural or anthro, let alone a mixture of them. Geoff S

    • Geoff Sherrington: “It is like the overall case in climate work, where the usual natural condition should have been researched and understood, before hurrying off to name a disaster agent, CO2, whose understanding is severely limited by lack of knowledge of the usual condition.

      Geoff, you are right of course, but you can’t raise taxes, eliminate fossil fuels, and form a One-World government going about it your way.

    • Parallels the position I have held since the start of this nonsense:
      IF additional CO2 pushes temperatures up, the most you can say is it should be x degrees warmer than it would be OTHERWISE, but WE HAVE NO IDEA WHAT THAT TEMPERATURE WOULD BE.

      Unfortunately, this gives the climastrologists an out. If temps level off or go down, they can claim we are in a natural cold period, made warmer because of us, but when the natural cold period become a natural warm period, our emissions are going to destroy life on earth. It will be worse than we thought!

      We should start seeing climate models reconstructing what the recent past climate would have been without CO2 warming, to further validate CO2’s climate impact (yeah, circular logic).

      • They can’t say that anymore… look at my comment further up.

        If they try that tactic, they’ll get chewed to bits by practitioners of the hard sciences.

        CAGW is well and truly dead. The climate alarmists refuse to bury its corpse in hopes they can tear a little more of the meat from its bones before it turns rancid. Little do they know, they’ve been eating rotten meat for quite some time.

        Now that we know the particle physics of the atmosphere, we can start prosecuting the climate fraudsters for their data manipulation, scare-mongering and waste of taxpayer dollars.

        “All radiative molecules play the part of atmospheric coolants at the temperature at which the combined translational mode energy of two colliding molecules exceeds the lowest vibrational mode quantum state energy of the radiative molecule. Below this temperature, they act to warm the atmosphere via the mechanism the climate alarmists claim happens all the time, but if that warming mechanism occurs below the tropopause, the net result is an increase of Convective Available Potential Energy, which increases convection, which is a net cooling process. So the alarmists, as usual, are wrong yet again, on every count.”

  10. Sorry to undermine two of your sacred cows Bob but the latest research shows the both the LIA and the MWP were weak localised events compared to modern AGW.

    Abstract
    “…we use global palaeoclimate reconstructions for the past 2,000 years, and find no evidence for preindustrial globally coherent cold and warm epochs. This lack of spatiotemporal coherence indicates that preindustrial forcing was not sufficient to produce globally synchronous extreme temperatures at multidecadal and centennial timescales. By contrast, we find that the warmest period of the past two millennia occurred during the twentieth century for more than 98 per cent of the globe. This provides strong evidence that anthropogenic global warming is not only unparalleled in terms of absolute temperatures5, but also unprecedented in spatial consistency within the context of the past 2,000 years.

    https://www.nature.com/articles/s41586-019-1401-2

    • Did you read the reference list by any chance? It is just the usual PAGES2K gang citing each others’ statistical fakes.

      • Why do most scientist agree that climate change is real though? It isn’t like all climate scientist are liberal, or are they?

    • The fact that this latest research disagrees with the vast bulk of research showing the warmth was worldwide suggests it’s designer research, e.g., “Get the look you want with Climate by Mann”. Now I better understand @ClimateOfGavin.

    • I just got that reference indirectly through Sigma Xi, a scientific (?) society that seems to get more than half its information from secondary sources like this.
      https://www.nbcnews.com/mach/science/climate-scientists-drive-stake-through-heart-skeptics-argument-ncna1033646 https://www.nature.com/articles/d41586-019-02179-2
      “ Consistent multidecadal variability in global temperature reconstructions and simulations over the Common Era”

      That’s quite a lot for the eleven references to cover in their advertisement for the paper which had a figure of a house at L’Anse aux Meadows in Newfoundland. Poking around I somehow got this one– “No evidence for globally coherent warm and cold periods over the preindustrial Common Era” https://www.nature.com/articles/s41586-019-1401-2

      Awful lot to read to check out all the references, especially at $9/ paper. (Rent or buy same price?)

    • “By contrast, we find that the warmest period of the past two millennia occurred during the twentieth century for more than 98 per cent of the globe.”

      So the warmest period of the past millennia happened last century. They must be talking about the 1930’s.

      The 1930’s would be before CO2 was a significant factor with regard to temperature, according to the IPCC. So the warmest period was in the 1930’s and current-day temperatures are actually cooler now than the 1930’s so CO2 cannot be a significant factor with regard to current-day temperatures, either, since the temperatures today are no warmer than the 1930’s and could be caused by Mother Nature just like the temperatures in the 1930’s were caused by Mother Nature.

      Mother Nature is the cause of past and current warming until proven otherwise. That is the default position everyone should assume.

    • The global climate is not uniform but there are some indicators of whether the average is up or down.

      Sea level lowered during the Little Ice Age. Glaciers generally advanced.

      With the modern warming, the sea level has started rising again and glaciers generally are retreating.

      With a plethora of studies based on all kinds of proxies, it’s good to have something reasonably reliable to provide context.

      Dr. Mann turned me into a skeptic because of his crappy science. It contradicted my knowledge of history. That provided my context. If you don’t know enough to have any kind of context, you will believe anything. That’s the goal of totalitarians everywhere.

    • Hmm lots of arm-waving but no one posts anything to refute the findings – like an abstract and a link to it.

      The LIA and the MWP obviously occured and had serious effects in some places at some times. But COMPARED to modern warming the areas affected and the timing are all over the place.

      Get used to it.

      • The observations about sea level and glaciers are well accepted. That does indicate that the global average temperature was lower during the LIA. That’s not arm waving. It’s just simple. If you insist on long impenetrable explanations, that probably means you are an easy victim for pseudo profound BS.

        The second mechanism relates to a potential inability to detect bullshit, which may cause one to confuse vagueness for profundity … link

        It’s up to you, personally, to counter my point. Just referencing someone else’s paper and saying “It’s in there” isn’t convincing, and certainly not worth our effort.

        • “That does indicate that the global average temperature was lower during the LIA.”

          No, it indicates that some ice, somewhere melted. It is not evidence of anything “global”. Africa , Australia and Asia might have been boiling hot at the same time.

          Modern warming dwarfs anything in extent, scale and rate of change since the Younger Dryas.

          • Loydo:

            “Modern warming dwarfs anything in extent, scale and rate of change since the Younger Dryas.”

            What modern warming? Do you mean maximum temperatures going up? Do you mean minimum temperatures going up? Do you mean both are going up?

            You are basing your statement on a global “average”. Do you have even the slightest understanding of what is actually happening? How can the average tell you anything?

          • No, it indicates that some ice, somewhere melted.

            LOL

            You have it exactly backwards. If sea levels go down and glaciers advance it means that water is freezing.

  11. There is a phenomenon called regression to the mean.
    A lot of speed cameras were installed at sites where there had been a run if accidents. They subsequently reduced in number and this was put down to the presence of the cameras.
    What nobody admitted to was that accidents had also reduced where there were no traffic cameras.

  12. The ice-age was one huge megadrought. In contrast, the peak of the inter-glacial caused greening of the Sahara and the end of the megadrought.

    Those who remember the 1970s famines and the “spreading desert” that used to occur before CO2 fertilisation reversed that effect, no doubt saw what was potentially the beginning of the next huge mega-drought aka ice-age.

    I’m not familiar with the droughts in the area of this research – nor even do I recognise what “American South West means”unless it off the coast of Chile, but it does seem to be putting the known evidence on its head.

    • Right. Technically, everyone from the western hemisphere is American. Should’ve specified “US southwest”.

  13. So this means either way, humans will suffer, be it from the magical CO2, which no government is stopping, even though companies like carbon engineering ltd can produce a replacement ultra low carbon fuel, for all our transport needs including planes and jets, and at the same time draw in massive amounts of co2 from the air. Or we allow the sun and mother nature to do what it does.

  14. and since when??? is a 10yr drounght a megadrought ffs! these idiots should have asked some aussies and saved shitloads of time n money
    but as soon as I saw eureka alert i started laughing
    wonder how the “modellers feel about the vid clip on adelaidenow.com.au last night sorry i couldnt bring it up to get a link(the clip)
    stating using Ai to run models for something used tonnes of energy co2 emissions were around 17cars worth etc
    had me grinning widely.

    • Megadroughts happen now once a year, previously they were rare and lasted for 200 years. /sarc

  15. The biggest contributor to mega droughts will be loss of soil, loss of vegetation covering soil and as a result a substrata incapable of supporting extensive plant ecosystems.

    If you look at wadis in deserts, they form courtesy of flash floods causing huge erosion due to no ability to absorb the moisture in organic matter. You can have significant rainfall having no useful outcomes due to lack of soil building capacity. As a result, air moisture through transpiration disappears and you get the dry desert heat by day and cold by night. That helps high pressure to dominate….until the next flash flood.

    That is how mega droughts establish and become entrenched.

    Of course, this requires a period when vegetation is denuded and dies/disappears. This can include actual droughts, but it can also simply include destruction of habitats through land clearance, loss of ecological balance through hunting etc. you only have to read the stories of what the first Europeans encountered to see that California had major wetlands in the San Joaquin river basin, extraordinary salmon runs, extensive forests and enormous bird migration routes. The ecology was vastly different and water retention was clearly vastly superior.

    If you watch how a small ecosystem evolves, firstly you get ground cover, then miners with deep tap roots and mineral-rich foliage to create soil, then bush and bramble emerges, before trees grow strongly through to create a mature system. So regeneration starts either promoting ground cover, tap roots and soil retention, with water diverted to regenerating areas to have some adequately watered areas rather than all areas getting insufficient water to make a difference.

    As for actual droughts: mega high pressures directing rainfall north, south and East. Is the evidence that SW mega droughts correlates with very wet forests in Washington, higher rainfall through the Mississippi/Ohio basin? The rain has to go somewhere after all. And these mega droughts were at the time of the ‘Medieval Climatic Optimum’, so other parts of the world may have been doing rather well.

    All in all, sounds like ‘California in Little Ice Ages, Europe in Climatic Optima’ would be a modern hunter-gatherers mantra?

    • “As for actual droughts: mega high pressures directing rainfall north, south and East. Is the evidence that SW mega droughts correlates with very wet forests in Washington, higher rainfall through the Mississippi/Ohio basin? The rain has to go somewhere after all. And these mega droughts were at the time of the ‘Medieval Climatic Optimum’, so other parts of the world may have been doing rather well.”

      I think you are on the right track. Let’s say a high-pressure system sets itself up centered on California. What will happen is the high-pressure, if it’s strong enough, will prevent storm systems from entering the area underneath the high-pressure system and will instead force the storms north up over the top of the high-pressure system or sometimes south of the high-pressure system, so those areas north and south and east of the high-pressure system get storm fronts coming through and get lots of rain, while those underneath the high-pressure system swelter in the heat.

      The year 1936 was one of the hottest on record in the United States, but it was also one of the coldest years on record in parts of the U.S., too. This can happen because a high-pressure system sits over the western two-thirds of the U.S. and keeps that area extremely hot, and when winter rolls around the very cold air up north can still get down into the United States by the north winds being pushed south and east around the high-pressure system boundary and into the Eastern U.S..

  16. History repeats itself .
    With all the supercomputers in the world today , it would not be too difficult to project future climate predictions on historical evidence rather than dubious climate modelling .

  17. Climate change could revive medieval megadroughts in US Southwest
    And?
    In other words the weather/climate that has happened before can happen again.

    • Well it’s like the aircon in the lab except you just need a bigger thermostat knob and more hands to turn it. What part of that irrefutable logic don’t you get with these climate changers?

  18. “today we are experiencing increased dryness in many locations around the globe due to human-made forces.” Wow, what a doubly-absurd claim, based on zero evidence. “Human- made forces”, eh? From which human-made orifice did that ridiculous phrase come?

  19. Funny, I’ve never heard it called to ‘American Southwest’, it’s always been the ‘Desert Southwest’. Their “Megadrought” is the norm for the 90% of the time earth is glaciated, and just normal variation in weather patterns in the interm.

  20. Well …. IF …. and I mean a big IF ….. the Magic Molecule theory is correct, then there should be an increase in evaporation and precipitation, thus making droughts less severe and frequent.

    Kids in California aren’t going to know what droughts are outside of scary history books.

  21. The American Southwest is a lowland desert with alpine forests. It receives the vast majority of its rain in the middle to late summer monsoon. How many times did they mention monsoon in their paper? Did they even study the North American Monsoon? Meh, it’s just climastrology, conclusions come before formulating hypotheses out of good ideas.

    At least their mechanism sounds plausible, strong and repeated La Ninas result in drought over much of North America. It’s convenient that the working [/s] hypothesis of man made climate weirding covers all possible outcomes, including more La Ninas, thus we are “stacking the deck” for more droughts…as soon as this period of relatively increased rainfall ends.

  22. Meh. Standard piece of research boiler-plate scare-mongering. Keywords: Could, might, maybe, perhaps, possible, plausible, etc, etc, and we have a model to “prove” it might.

  23. The Warm Blob that established itself off the coast of California a few years ago would seem to me to be a perfect study subject for these scientists.

    The Warm Blob was a persistent high-pressure system that sat off the California coast for a long time and caused the temperature of the water underneath it to become warmer than the surrounding ocean. A Heatwave on the ocean, if you will.

    If they can figure out why this happened, it would go a long way, I would think, towards understanding this phenomenon.

    If this high-pressure system had established itself over California instead of out in the ocean, then California and surrounding areas would have experienced a serious heatwave.

    • Actually the so called blob was only an area of anomalous warmth…IOW normal than what has been measured to be average for the areas in question.
      A look at the actual temps of the water showed no such blob of warm water at all.
      If one was just looking at a map of sea surface temps…there was no blab whatsoever.

      • “Actually the so called blob was only an area of anomalous warmth…IOW normal than what has been measured to be average for the areas in question.
        A look at the actual temps of the water showed no such blob of warm water at all.”

        https://en.wikipedia.org/wiki/The_Blob_(Pacific_Ocean)

        “In February 2014, the temperature of the Blob was around 2.5 °C (4.5 °F) warmer than what was usual for the time of year.[8][11]

        A NOAA scientist noted in September 2014, based on ocean temperature records, that the North Pacific Ocean had not previously experienced temperatures so warm since climatologists began taking recordings”

        end excerpt

        Contrary to the information in Wikipedia, the warmer water was only a few meters deep, not 90 meters.

        When the Warm Blob first popped up, the thinking was it must be being driven by underwater volcanic activity but it was later found the higher-temperature water was only a few meters deep which ruled out heat coming up from the ocean floor.

        • I do not doubt it.
          But what I was referring to is somewhat different: If one looked at a map of actual SST at the time the blob was extant, it was no where to be seen.
          It only showed up on anomaly maps.
          IOW, it was not “and caused the temperature of the water underneath it to become warmer than the surrounding ocean.”
          I can recall at the time that the articles on the blob were being published and discussed, looking at SST maps and thinking, “Huh? Where?”
          There was no sign or indication of a blob of warm water…just not as cold as is typical for the time of year and location in question.
          The isotherms were not in the shape of any closed blobs, and there was no actual warm water.
          I am also trying to understand how warm water was said to decrease rainfall downwind, or cause a rise in atmospheric pressure.
          Warm water adds moisture to the air more so than cooler water, and warmth causes air to rise from the surface, which is associated with low pressure.
          IMO, the whole thing was likely a non-issue.
          We have seen the same sorts of weather anomalies in the adjacent land areas with water temp conditions in every possible state.
          It seems to me that when thousands of people are looking at, and billions of dollars are being thrown at, what is in fact a non-existent problem, then those people will use those dollars to find something to show or to say, whether or not there is anything to be shown or said.

          • Here’s a link to a good article on the Warm Blob;

            https://www.sciencemag.org/news/2019/01/ocean-heat-waves-pacific-s-deadly-blob-could-become-new-normal

            The article names several possible sources of warm water and how everything interacted.

            What I find the most interesting about the Warm Blob is the high-pressure system associated with it was in the area for over three years.

            Think about the calamity that would happen if that high-pressure system sat over the western U.S. for that long. It would be another Dust Bowl-type disaster.

            California has had very long droughts in the past and a weather pattern like what fostered the Warm Blob could also be responsible for longterm droughts in the U.S. We need more study on those weather patterns.

          • Personally, unless and until the present paradigm remains in place, where every thought or study that is not intended to back up the CAGW narrative is blocked or ignored, then there is little reason or sense in doling out more money to study such things.
            At this point every study seems to make people stupider.
            The state of knowledge is not advancing, it is being torn to shreds.
            Besides, is anyone going to be able to prevent or alter such weather patterns?
            I doubt they are even forecastable given present knowledge and skill, either in advance, or as to when they will end once they have begun.

  24. In satellite imagery, Stratospheric Intrusions are identified by very low moisture levels in the water vapor channels (6.2, 6.5, and 6.9 micron). Along with the dry air, Stratospheric Intrusions bring high amounts of ozone into the tropospheric column and possibly near the surface. This may be harmful to some people with breathing impairments. Stratospheric Intrusions are more common in the winter/spring months and are more frequent DURING LA NINA PERIODS.
    https://www.cpc.ncep.noaa.gov/products/stratosphere/strat_int/

  25. “The authors found that ocean temperature conditions plus high radiative forcing — when Earth absorbs more sunlight than it radiates back into space — play important roles in triggering megadroughts.”

    For the same reason Europe enjoyed/suffered a Medieval Warm Period/Little Ice Age due to ocean temperatures in the Atlantic, the USA west suffered droughts due to Pacific Ocean temperatures; therefore, citing the alleged involvement of the devil’s molecule for future droughts is unnecessary.

  26. If you boil this post down you get:

    If scientists can understand … A study … provides the … theory …
    The study suggests … due to climate change.
    scientists … projected … may bring …
    By reconstructing … likely due … conditions were estimated .
    … events will remain difficult for scientists to predict. … future … remains difficult to simulate.
    Nevertheless,… climate change … in the future.
    … in the future … it could lead to
    … Climate change … increased possibility … in the future ..

    next step:

    theory … suggests … due to climate change … projected … may bring … likely … estimated … difficult … to predict. … future … difficult to simulate. … in the future … in the future … it could lead to … Climate change … possibility … in the future ..

    I conclude that this is the Seinfeld show. A show about nothing.

  27. This pattern goes back millenia, not centuries. The climate of the American Southwest is simply returning to its normal oscillation after a little over a century of abnormally high precipitation. Wild oscillation is the historic (or rather pre-historic) normal for the area. The average Southwest precipitation over the past 2000 years is 2/3 of what the wet 20th Century made us think was normal. A real drought by Southwestern standards is 1/3 of what we think is normal.

    And mega-droughts (really long periods of real Southwestern drought) can last for centuries.

    http://www.amazon.com/gp/product/B00D4EWHPU/ref=oh_aui_d_detailpage_o02_?ie=UTF8&psc=1, The West without Water: What Past Floods, Droughts, and Other Climatic Clues Tell Us about Tomorrow, Ingram, B. Lynn, and Malamud-Roam, Frances, 2013, University of California Press

    http://ngm.nationalgeographic.com/2008/02/drying-west/kunzig-text, Drying of the West, (February 2008), National Geographic, Kunzig, Robert

  28. A mega drought (which is presumably the reciprocal of a micro drought) has to last for a long time, right?

    Longer than the existence of Los Angeles, which has no right to continue existing with insufficient local rainfall to support such a large population? Funny how humans find a way to circumvent natural obstacles.

    With appropriate application of cheap nuclear power, Los Angeles could easily double in size and yet still provide ample water for its inhabitants via desalination plants. No sacrifices needed, apart from the abandonment of the green gods.

  29. Yet another “But this time it’s different!” argument.
    We’ve accumulated knowledge, but we haven’t gotten smarter in the last 10,000 years.

  30. It is going to get so warm that we will be growing pineapples in Alberta year round. The far north will become the new Florida and Canadians will head north instead of south for winter heat. That said , I have a terrific piece of oceanfront that has great potential once the ice is gone. I will sell it at a real good price.

  31. “Nevertheless, the researchers conclude that human-driven climate change is stacking the deck towards more megadroughts in the future.

    “Because you increase the baseline aridity, in the future when you have a big La Niña, or several of them in a row, it could lead to megadroughts in the American West,” explained lead author Nathan Steiger, a Lamont-Doherty Earth Observatory hydroclimatologist.”

    And now this “researchers” hopefully work on a practical solution to show how “human” produces more than 2 observable La Niñas in a row.

  32. “There are predictions about future trends in temperatures, aridity, and sea surface temperatures, but future El Niño and La Niña activity remains difficult to simulate. Nevertheless, the researchers conclude that human-driven climate change is stacking the deck towards more megadroughts in the future.”
    _________________________________________________________

    Wie verursachen diese Menschen “Duerreperioden” – kippen sie ueberschuessige Feuchtigkeit den Bach runter?

    How do these people cause droughts? They empty excess humidity down the rivers?

    Comment ces personnes provoquent-elles la sécheresse? vider l’excès d’humidité dans les égouts?

  33. There’s only ONE way how man could get rid of unwanted excess humidity aka “water” on Planet Earth: send buckets full of water to outer space, e.g. Mars or Moon.

    Do this “researchers” know about high secret activities of NASA in one or the other way?
    _________________________________________________________

    In the real world it’s the other way round: everyday meteors und dust rain water down to planet Earth in unknown quantities.

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