A likely to be wrong claim: “Colorado River flows will keep shrinking as climate warms”

From the UNIVERSITY OF ARIZONA and the department of “we are in permanent drought in California… oh, wait” comes this claim that is surely little more than another modeling fantasy from Jonathan Overpeck.

Colorado River flows will keep shrinking as climate warms

The US Bureau of Reclamation estimates annual natural upper Colorado River flow based on data recorded from streamgages at Lees Ferry. At that location, Colorado River streamflow reflects water that has drained from the upper basin, which includes Colorado, Wyoming, Utah and New Mexico. CREDIT U.S. Geological Survey

The US Bureau of Reclamation estimates annual natural upper Colorado River flow based on data recorded from streamgages at Lees Ferry. At that location, Colorado River streamflow reflects water that has drained from the upper basin, which includes Colorado, Wyoming, Utah and New Mexico. CREDIT U.S. Geological Survey

Warming in the 21st century reduced Colorado River flows by at least 0.5 million acre-feet, about the amount of water used by 2 million people for one year, according to new research from the University of Arizona and Colorado State University.

The research is the first to quantify the different effects of temperature and precipitation on recent Colorado River flow, said authors Bradley Udall of CSU and Jonathan Overpeck of the UA.

“This paper is the first to show the large role that warming temperatures are playing in reducing the flows of the Colorado River,” said Overpeck, UA Regents’ Professor of Geosciences and of Hydrology and Atmospheric Sciences and director of the UA Institute of the Environment.

From 2000-2014, the river’s flows declined to only 81 percent of the 20th-century average, a reduction of about 2.9 million acre-feet of water per year. One acre-foot of water will serve a family of four for one year, according to the U.S. Bureau of Reclamation.

From one-sixth to one-half of the 21st-century reduction in flow can be attributed to the higher temperatures since 2000, report Udall and Overpeck. Their analysis shows as temperature continues to increase with climate change, Colorado River flows will continue to decline.

Current climate change models indicate temperatures will increase as long as humans continue to emit greenhouse gases into the atmosphere, but the projections of future precipitation are far less certain.

Forty million people rely on the Colorado River for water, according to the U.S. Bureau of Reclamation. The river supplies water to seven U.S. Western states plus the Mexican states of Sonora and Baja California.

Udall, a senior water and climate scientist/scholar at CSU’s Colorado Water Institute, said, “The future of Colorado River is far less rosy than other recent assessments have portrayed. A clear message to water managers is that they need to plan for significantly lower river flows.”

The study’s findings, he said, “provide a sobering look at future Colorado River flows.”

The Colorado River Basin has been in a drought since 2000. Previous research has shown the region’s risk of a megadrought–one lasting more than 20 years–rises as temperatures increase.

Overpeck said, “We’re the first to make the case that warming alone could cause Colorado River flow declines of 30 percent by midcentury and over 50 percent by the end of the century if greenhouse gas emissions continue unabated.”

The paper by Udall and Overpeck, “The 21st Century Colorado River Hot Drought and Implications for the Future,” went online Feb. 17 in the American Geophysical Union journal Water Resources Research. The Colorado Water Institute, National Science Foundation, the National Oceanic and Atmospheric Administration and the U.S. Geological Survey funded the research.

The team began its investigation because Udall learned that recent Colorado flows were lower than managers expected given the amount of precipitation. The two researchers wanted to provide water managers with insight into how future projections of temperature and precipitation for the Colorado River Basin would affect the river’s flows.

Udall and Overpeck began by looking at the drought years of 2000-2014. About 85 percent of the river’s flow originates as precipitation in the Upper Basin–the part of the river that drains portions of Wyoming, Utah, Colorado and New Mexico. The team found during 2000-2014, temperatures in the river’s Upper Basin were 1.6 degrees F (0.9 C) higher than the average for the previous 105 years.

To see how increased temperatures might contribute to the reductions in the river’s flow that have been observed since 2000, Udall and Overpeck reviewed and synthesized 25 years of research about how climate and climate change have and will affect the region and how temperature and precipitation affect the river’s flows.

Water loss increases as temperatures rise because plants use more water, and higher temperatures increase evaporative loss from the soil and from the water surface and lengthen the growing season.

In previous research, Overpeck and other colleagues showed current climate models simulated 20th-century conditions well, but the models cannot simulate the 20- to 60-year megadroughts known to have occurred in the past. Moreover, many of those models did not reproduce the current drought.

Those researchers and others suggest the risk of a multidecadal drought in the Southwest in the 21st century is much higher than climate models indicate and that as temperatures increase, the risk of such a drought increases.

Udall said, “A megadrought in this century will throw all our operating rules out the window.”

Udall and Overpeck found all current climate models agree that temperatures in the Colorado River Basin will continue rising if the emission of greenhouse gases is not curbed. However, the models’ predictions of future precipitation in the Basin have much more uncertainty.

Overpeck said, “Even if the precipitation does increase, our work indicates that there are likely to be drought periods as long as several decades when precipitation will still fall below normal.”

The new study suggests Colorado River flows will continue to decline.

Udall said, “I was surprised at the extent to which the uncertain precipitation aspects of the current projections hid the temperature-induced flow declines.”

The U.S. Bureau of Reclamation lumps temperature and precipitation together in its projections of Colorado River flow, he said.

“Current planning understates the challenge that climate change poses to the water supplies in the American Southwest,” Udall said. “My goal is to help water managers incorporate this information into their long-term planning efforts.”

###

 

One has only to look at Jonathan Overpeck’s Twitter Feed to realize that the man is little more than a doomsayer that will believe almost any claim associated with warming, especially his own.

“The first principle is that you must not fool yourself and you are the easiest person to fool.” – Richard P. Feynman

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152 thoughts on “A likely to be wrong claim: “Colorado River flows will keep shrinking as climate warms”

  1. Ugh UGH the “average” trick.

    “81 percent of the 20th-century average” is an utterly meaningless thing to say, and is crafted to create an imaginary cause.

    More cargo cult science

    • …and the 20th century is one hundred years. a mere 0.00000002222222 of geological time, and only about 0.00833333333333 of the period since the last glacial maximum. Herein lies a complete speculation, based on estimates that admit to knowing nothing about how the hydrological cycle affects climate model inputs…or outcomes. I wonder what their final expense tally was, for essentially blowing smoke up the collective patoot?

      • The figures could very likely be true though perhaps not for the reasons intoned in the report.
        While the Colorado River flows have been reduced over the last 15 years (21st century) by about 1/2m acre feet (or about 2m people) is this caused by heating and less precipitation in the watershed or is it from ever increasing .water usage needed to sustain an additional 2m people added to the region over the last 15 years.
        Further, the Mid Century and End Century figures could also come to pass simply through population increase and it’s inherent demand increase on the water source, without the need for a Heat load increase.
        If, as expected, the increasing sea surface temperatures bring about a (semi)permanent El Niño condition, would this not mean increasing atmospheric water and thereby increasing El Niño induced rain events?

    • There is a term for using averages (and more generally, statistics) like that. It’s called ‘statisticulation’. The term appears in ‘How to Lie with Statistics’.

    • “average” is the ultimate low-pass filter. Removes any hint of huge variability in actual precipitation and river flows and paints the past as some idyllic Garden of Eden. And fossil fuels which emit CO2 are the serpent that tempted and has destroyed the Garden.

      That sums up the climate change religion’s central dogma.

  2. “Those researchers and others suggest the risk of a multidecadal drought in the Southwest in the 21st century is much higher than climate models indicate and that as temperatures increase, the risk of such a drought increases.”

    So lets get this straight.
    A prediction based on half baked models may be worse than the prediction of other half baked models.

    Reading between the lines “we have almost no idea what will happen”. Pure obfuscation of that truth.

    • When your claim is about risk of drought at the 21 century, how the beep you can validate that claim? Climate science is incapable of doing any predictions that be useful. What you need are robust findings, things that will happen 99.9995% certain and happen sooner than in 100 years. If you predict just anything and far in future, you are always right and long dead before anybody can question you. There is a risk we run into problems by using alarmist policies! Prove me wrong!

      • tell that to the southern hemisphere… till now it’s cyclone season is really… a major drought of hurricanes…

    • Well you know the proof of this is that California is now in a state of permanent drought.

      Oh wait, it isn’t???

      Never mind.

  3. All territory that makes use of Colorado River water should be immediately evacuated for now and for all time. Problem solved. If no one makes use of the river water then It will not matter how much exists.

    • +1 You know, drought is defined by use exceeding resources.

      I’m quite certain the scarcity of usable water in California is a result of very complicated leftist thinking where your goal is not to get more water, but to not get any water. That way you can feel yourself important and do leftist policies which go into detail about how people use water for their good.

      As Wired said, the drought is forever, because it is not about water but people.

      • There are too many people in the entire Southwest due to dams and other systems. It is very dry most of history in these regions. Modern cities use a lot of water. A 100 year drought is not unknown in the deserts were millions of people now live.

  4. “Water loss increases as temperatures rise because plants use more water, and higher temperatures increase evaporative loss from the soil and from the water surface and lengthen the growing season.”

    Meanwhile, increased atmospheric Co2 will reduce the water required by plant life and growing seasons will increase.

    Extraordinary how these ‘scientists’ conveniently ignore/forget/are ignorant of, basic science even a layman like me recognises.

    Which doesn’t help the Colorado river levels, of course. What would help, however, is if ‘catastrophic climate change’ can’t be stopped (and whilst it’s unlikely to be catastrophic, it can’t be stopped) less people were using water from the river.

    Which plays neatly into the greens humanity hating nature. They can always cull all those nasty humans drinking water. That would help.

    Meanwhile, the American taxpayer will shell out shedfuls of dosh for this guy’s doom-laden predictions that have never come to pass over the last 40 years.

    • Easy to overlook where they mention that over 40 million people rely on a river that runs through a desert!
      When 40 million people live in a desert, and they all want green lawns, trees and hot showers a few times a day…Maybe that is the problem?
      Just guessing.

  5. So in only 15 years of data, they were able to deduce that temperature was a causation of lower water flow rather than simply a correlation?

  6. serious question:

    CERN’s cloud experiment has shown us a lot about cloud formation. Sulfuric acid pollution is (can be) a huge driver in cloud formation.

    Can’t we build industrial plants upwind of the western slope of the Rockies and thus trigger more rain/snow?

    • We need jobs here after 10 years of Democrat rule in the state house that cause 3000 families to leave our happy little valley. Any industry would be welcome.

    • Yawn. 30 years of Chicken-Little subsidized pronouncements are getting a touch boring. The warming has ended, but the malady lingers on.

      • The Southwest has been unusually wet most of the time during the entire 20th century. We know for certain there have been epic droughts in the past which destroyed for example, the Anasazi civilization hundreds of years ago.

      • Replaying snowstorms and storms from the CAGW playbook, ” see warm air holds more moisture “. If the planet is warming, how is it that there will be a mega drought? I’m pretty sure Griff is saying that about the rains in California. Before the rains were delicate, but now “it’s real time diaster played out before our eyes”.
        It’d be more believable if they had said it was going to be wetter with more flooding. Drought in the southwest is like predicting I’m very likely to loose my money in Las Vegas.

  7. In the late ’70s, I remember a reading an article about the Colorado River titled “The River That No Longer Reaches The Sea” (or something like that) for the Geography course I was taking in college. When I lived in SoCal in the early ’80s, I remember reading an article in the LA Times about how northern and southern California have historically squabbled over each other’s allotments of Colorado River water. Apparently, this issue is nothing new, and is simply a function of too many entities sucking it dry.

    • …Maybe they should buy the Aussies unused Desalination plants (that were built because of the coming permanent drought drought that didn’t happen) to save them from the permanent drought that probably won’t happen ??…Just in case..!

      • …A drought drought is three times as bad as a simple drought !! That’s my story and I’m sticking to it ! D’oh !

      • It was the droughtiest drought to ever drought a drought. Drought squared in other words. And they’ll never see a drop of water ever again, unless the Dam brakes. Them they’ll be drowning in drought.

        •¿●

      • No need to buy others’ white elephants. CA is building it’s own desalination plants. We knew the rains were coming when Santa Barbara decided to bring its desalination plant out of moth balls (it was built and finished just as the last big drought changed to flooding) and spend money on refurbishment to make it operational again. Seems like it will be placed into cold storage once again.

      • Rocketscientist:
        Santa Barbara was bypassed by the atmospheric rivers. That region is still in drought trouble.

      • That was true about Santa Barbara a month ago but the situation has changed over the last 3 weeks. Countywide they have now received 179% of average rainfall to date and 124% of the full water year rainfall. The reservoir levels have begun to respond and have gone from 20% of capacity to 40% of capacity.

    • When I was a child we would go to where the Colorado River exits to Baja California’s ocean in Mexico and a child could jump over the water there.

    • If anyone has access to the paper please let us know if they accounted for population growth and water consumption in the catchment area above the gauge. Any increase in irrigation or industrial use upstream?

  8. “Flows are 18% less than twentieth century average”
    ” one sixth to one half of decrease is due to warming”
    – gee I wonder what caused the rest? As much as 5/6 of flow decline was NOT caused by warming. But the study was about dueling computer models, not the actual river.
    ” … as long as humans continue emitting CO2 … blah, blah, blah, send money,blah blah”

    The party’s over dude – didn’t you get the text?

    • I ill go out on a limb here and guess that 50% of all 20th century readings were less than the 20th century average.

      I know, that’s crazy talk.

      • George Carlin had an amusing quip along the same thought: “Think of how stupid the average person is, and realize half of them are stupider than that.”

      • Absolutely completely nuts…

        I’ll go out on a limb here too, and guess that if the numbers were run again (with respect to the subject paper/article) at the end of this rain year, the referenced flows would not be ANY% below the 20th century average.

        The flows would be at or X% above the 20th century average. Then they would have to pretzel the data and themselves to assign a percent increase to the warming.

  9. Nonsense.

    Precipitation is a function of chaotic fluctuation of air mass motion.
    One could ostensibly project increased water vapour might lead to increased precip.
    But one cannot predict the weather of the future, beyond seven days or so.

    Drought might occur, but it also might occur with a constant or lower global temperature.

    This analysis is nonsense.

    • Note that the models, which they falsely claim replicate temperature changes well, rely on water vapor amplification for the projected levels of warming they incorrectly project.
      So more water in the air leads to drought?
      Yeah…sure it does.
      I wonder if they are taking into account the unusually high flow rates that occured in the early 20th century?
      Are they figuring those flows were “normal”?

      In any case, if history is any guide, all that need happen to increase river flows to record levels is for these always wrong lame-oids to declare a permanent drought. Works like a charm.

    • Even weekly forecasts can still be hit or miss, depending on the region.

      We have a quip here in Oklahoma: If you don’t like today’s weather, go back inside and wait 15 minutes.

  10. Once again climatism misinforms and misdirects on environmental hazards. Now fears of long-term drought in the US Southwest are put forward and blamed on “climate change”, code for burning fossil fuels. NASA: Megadrought Lasting Decades Is 99% Certain in American Southwest

    Unsurprisingly, when you read past the headlines, you find that the real issue is man-made all right: water and land usage by growing populations of residents in the region.

    https://rclutz.wordpress.com/2016/10/08/man-made-drought-in-us-southwest/

  11. “the man is little more than a doomsayer that will believe almost any claim associated with warming, especially his own.”

    whereas some websites consist entirely of finding studies which involve climate change and publicly ‘disbelieving’ them…

    (Research seems perfectly reasonable to me)

    • Geoff your definition of “reasonable” is a new one, known only to climate change true believers and fundamentalist bible thumpers.

      • Please don’t insult the fundamentalists. They will, at least, get you a bible on request. (Getting data from climate sciactivists, on the other hand…)

    • Reasonable on your home planet means believing two impossible things before breakfast of green eggs.

      Explain please how on earth more CO2 is supposed to increase H2O in the air, hence precipitation, yet also create droughts.

      Clearly this ludicrous pack of lies was perpetrated before the atmospheric rivers started drowning the SW and snow buried the NW basins of the Rio Colorado.

      • Chimp you will be surprised to know that there is such a thing as a green egg! Barred Plymouth Rock black hens lay green eggs. There is also a Chilean egg layer that also does so. See also pink, chocolate brown, Rose and blue eggs – google them.

    • Here’s why it is nonsense –

      the press release states, in direct contradiction of the implications:

      “In previous research, Overpeck and other colleagues showed current climate models simulated 20th-century conditions well, but the models cannot simulate the 20- to 60-year megadroughts known to have occurred in the past. Moreover, many of those models did not reproduce the current drought.”

      This is not at all surprising – droughts are the result of precipitation deficit, and precipitation is the result of chaotic fluid flow which is not predictable past 7 days or so.

      Chaotic fluid flow can yield drought with higher, lower, or just about the same global temperatures because global temperature does not determine fluid flow.

      • In most of the world, if your model fails to reproduce mega-droughts that are known to occur, you would conclude that there is something wrong with your model and attempt to fix the model, or scrap it if it can’t be fixed.
        In climastrology, you declare that this proves that future droughts are going to be worse than we thought.

    • In Griffies world, it’s all about belief or disbelief. There is no room for actual data or even thinking.

      Notice how Griff’s “seems perfectly reasonable” trumps actual data and logic presented by others.

    • Yet another contentious post, uttterly content-free and purely designed to provoke a reaction.

      Skanky, you’re just a sad, patronising little clown dancer extracting the urine, aren’t you?

      You think it’s amusing to taunt people who are so much more scientifically knowledgeable and literate than you that you can’t even concieve of how superior they are, by telling the same lies about the same things over and over again, even after you’ve been told how and why you’re wrong, complete with chapter and verse.

      You do this because anyone who believe anyone who doesn’t share your quasi-religious belief in AGW is intellectually and morally inferior to you and you sanctimonious Guardianista clique, so you can insult the informed AGW sceptics with a clear conscience, you can lie about the professional qualifications of experts in climate science fields, and you can repeat your egregious windup games over and over and over againsmirking to yourself over how you’ve got one over on the silly den1ers – and what is more you even get paid to do it.

      What a truly unpleasant, conscience-free, pathetic specimen of humanity you are.

  12. The drought is permanent. The recent flooding is just a statistical anomaly. Probably experimental error. We can adjust the gauges and measure again. Probably just a calibration problem.
    Loads of houses get recalibrated into rubble. Ignore it. Nothing to see here.

  13. Meaningless drivel designed to scare the population. Of course a megadrought will cause water problems. I would have come to that conclusion without all of the prestige building titles thrown in.

  14. Surely their funding body should be asking serious questions about why they have wasted their money on such stupid research, the results of which seem to have been created just to justify the funding.

  15. So we can take this mega drought to the bank? So is this an offical policy statement or wishful thinking? I was thinking that in light of a dam collapse from lack of maintance due to continued and very vocal advocacy about a mega drought, that if my property was adversely impacted, I might want to haul some of these people into court.
    Now, when it comes to weather/climate anybody can be wrong. However, in recent memory water was overflowing the top of Hoover Dam. The Army Corp of Engineers were highly criticized for the down stream flooding that occurred. So are they drawing down the lake levels in response to when the dam might be filled to capacity again or are they playing into the hands of the warming activists? Every piece of water in the western US is owned by somebody. I think they have a really good idea of how much water will be out there. They just don’t know when.
    It’s really easy to claim a mega drought in an arid to semi arid environment. That could happen. That’s why they built the dam in the first place. Tell me something useful, like when a severe drought will hit the Delaware River basin, like 1963 when it was literally a trickle. Which I’m sure will be a direct cause of global warming and has never happened before or been this bad. I’m waiting for a prediction on that. The last semi drought in New Jersey, I didn’t see the Passaic Valley Water Authority remove any of the silt from their reservoirs.
    California isn’t green in parts because of delicate rains. It’s green from irrigation. Otherwise it’s brown, dry, and desert like.

    • Hoover dam never over topped but that huge spillway was used about 20 years ago and eroded the structure. Downstream flooding was an issue.

      • I think the lake has only been 100% 2 years during its entire existence. Isn’t the “planned maximum” something like 65%?

      • I can’t find it, so you may be right about spilling over the Hoover Dam. But it seems I was there when the road across the dam was closed. It seems I have a picture in my mind of how the water looked flowing over it. I never thought I’d have a need to document such things or at least for myself and where I saw it.

  16. By applying the Gore effect we can predict in the next rainy season or two the Colorado river watershed will experience “record” rains and flooding risk. Climate/CO2 obsessed people are basically nearly always wrong.

  17. My goodness, I doubt such a paper and conclusions would past muster in high school!

    Model based basics then overlayered with statements about uncertain precipitation levels, perhaps it will rain more (warmer planet, means an overall wetter planet), perhaps it won’t. Evaporation from soil, where does that moisture go and when and where does it come down?

    Plants use more water! Have they not heard that plants use far less water in face of increased CO2 levels, not more. This lot need to redo their high school education and come back in a few years.

  18. We need to think ahead before it’s too late. In 5 billion years, the sun will turn into a red giant and vaporize ALL water on the planet. This must not happen. Think of the fish! That’s why I’m starting a kickstarter fund to solve it once and for all. Join me. Together we can extinguish the sun.

  19. It is truly sad that after thirty years of failed predictions that the alarmists and doomsters seem to be unable to apply their own precautionary principle to avoid yet again making an absurdly unverifiable claim and making themselves openly and obviously unable to learn from experience.

    • When making random predictions, some must happen to be correct. That’s what they are doing, hoping to get a correct prediction – excuse me, these days they don’t make predictions, they make projections. The only problem is that they can’t tell which projection is the correct one. Out of an abundance of caution, they treat all of them as correct.

  20. From the interview: Udall said, “I was surprised at the extent to which the uncertain precipitation aspects of the current projections hid the temperature-induced flow declines.”

    Interesting. So there is a temperature-only component that can be separated from the precipitation. The only one that comes to mind is the possibility of increased rate of evaporation as the temperature soars by 0.02 degrees per year.

  21. How much deadly CO2 emissions would be saved if all climate scientists stopped their work, stayed at home, and sat very still? They would be doing their part. Just a thought.

  22. “Water loss increases as temperatures rise because plants use more water, and higher temperatures increase evaporative loss from the soil and from the water surface and lengthen the growing season.”

    This may be true for a hot day, but is it not true for a generally, globally, warmer climate. When the entire system is warmer the humidity rises. The evaporation rate depends on the humidity of the passing air. If the entire system warms and the absolute humidity follows, then the evaporation rate remains the same.

    If the mountains are significant as precipitates, like the BC Coast, then rainfall will tend to increase with higher water vapour as the delta T from sea level to the top of the atmosphere increases. This the mountain will produce more condensate than when the delta T is lower and the air less humid.

    The prediction is conceptually flawed. With increased global temperatures the rain will increase at high altitude and it will penetrate further into the dry interior.

  23. How can any scientist who was involved in Climategate show his face in public ever again? Have we such short memories ?
    .

    • Cuz no one in guvmint, academia or the media has held the c0nspirators accountable for their crymes.

  24. Increased use of water for agriculture or just form population rise will slow the flow of the Colorado river.

    That seems like a plausible trend.

    This prediction may well come true.

      • Oh yes. I quite agree with you.
        But if it does come right for the wrong reason we will find there are many loud voices in the media who won’t care about little things like causality, reason or truth.

  25. “Current climate change models indicate temperatures will increase as long as humans continue to emit greenhouse gases into the atmosphere, but the projections of future precipitation are far less certain.”

    Sums up as, Overpeck telling his crew:
    “Okay guys and gals, lets take the failed circular logic GCM supercomputer outputs, throw in completely uncertain, highly variable precipitation scenarios, and then collaborate to write a manuscript with the outcomes we want to drive multi-trillion dollar policy. And then we’ll use the alarm to scare-up more grant monies for our (over-staffed and over-stuffed) environmental center.”

  26. Did they take into account that the Moffat Tunnel diverts nearly a million acre feet of water per year from the Colorado River basin to supply Denver and Englewood, east of the continental divide?

  27. there are other factors contributing to the decline of flow on the colorado:
    1. loss of aspen trees which have a higher runoff potential than conifers, 2.5 million acres lost to conifer encroachment.
    2.reservoirs and diversions – 2200 on the utah side, 485 diversion, on the colorado side 11000 reservoirs and impoundments and nearly 33,000 water right diverions and 7000 wells. management on these are not consistent thru time.
    3. accuracy of measurment – inflow to lake powell is gaged at +/- 15% accuracy
    4. changes in land management, grazing, logging, contour trenching to prevent runoff and flooding, etc.
    5. mining practices that were also logging practices – cutting timber, removing trees for mines, making charcoal for smelting in the 1800-1940’s. less trees = more runoff
    6. smokey bear – the agent of greatest environmental/watershed change in history. putting out fires has led to forests of conifers that used to have 10-20 trees per acre to upwards of 50-200 per acre. more trees=less runoff.
    so you have agriculture, mining, diversions, dams, fire, logging, grazing, aspens, groundwater withdrawals, and watershed restoration all going on and every change in streamflow is attributable to climate change to a level barely detectable by the measurement accuracy of the gage?
    its convenient to forget a lot of little things if your objective is the one big thing.

  28. From 2000-2014, the river’s flows declined to only 81 percent of the 20th-century average, a reduction of about 2.9 million acre-feet of water per year.

    This translates to 2.9×14 is 40.6 million acre-feet in 14 years.

    Warming in the 21st century reduced Colorado River flows by at least 0.5 million acre-feet,

    This means 0.5 million acre-feet in 14 years.
    Which one is correct ?

    Forty million people rely on the Colorado River for water, according to the U.S. Bureau of Reclamation. The river supplies water to seven U.S. Western states plus the Mexican states of Sonora and Baja California.

    Forty million people would require 10 million acre-feet as per this Paper.

    The actual water for an average U.S. family of four is 400 Gallons per day which is about one eighth of what is claimed here.

    • “The actual water for an average U.S. family of four is 400 Gallons per day which is about one eighth of what is claimed here.”

      He may be counting agricultural and industrial uses on a per capita basis.

    • Water use is around around 100 gpcd (gallons per capita day) including domestic, commercial, and light industrial (industry that does not use water in process). Irrigation is not included,not ag nor city lawns. Wet process industries are also not included in that amount. The number is a design number and is therefor slightly high to reflect a peak day rather than an average.

      • I checked my local city website and it showed 2016 water use was 106 gallons per day per capita. It also showed residential use was only 61% of that amount.

  29. im also not sure what streamflow record was used and how it was derived – if they used the ‘official’ adjusted streamflow record that is used by the national weather service and the Natural resources conservation service for streamflow forecasting – used by the bureau of reclamation for dam management, that record is adjusted for 17 major diversions and 17 major diversions. thats all. note in the comment above how many reservoirs and diversions there actually are. they may have done their own adjustments but i doubt the encompassed them all….

  30. So we have a guy whose prof of geosciences and hydrology AND atmospheric sciences AND environment and… Looking at a river gage doesn’t make you a hydrologist. I wonder if he’s ever read and understood Tolman, or has burnt midnight oil over the Navier Stokes equations, or the chemistry and biochemistry of soils, seawater, aerosols, ecology…. In the grant industry, I guess casting your net as wide as possible is the game and what a combo when you can join forces with ‘a senior water and climate scientist/scholar’!

    Steve McIntyre was correct when he remarked that from the quality of the work of most of these university profs and researchers in climate science, they would have been lucky to have obtained a job as a high school science teacher in an earlier generation (I would say maybe two or three generations ago). A bloody Colorado River mud ‘scholar’ indeed. The North American education system is turning out designer brains in preparation for the international neomarxbrothers show.

  31. Edit

    The actual water for an average U.S. family of four is 400 Gallons per day which is about one eighth of what is claimed here.

    The actual water for an average U.S. family of four is 400 Gallons per day which is less than half of 893 Gallons per family per day ( One acre-foot of water will serve a family of four for one year ) claimed here.

  32. In 1998, I was part of a field seminar (geologically related) that spent a lot of time around the Green and Colorado Rivers. There were these beautiful trees all along the bank(s), with the most amazing and delicate flowers.

    I learned that these trees are called tamarisk. They were originally imported as their root systems had the characteristic of binding soil very tightly, and reducing or eliminating erosion. They were planted along parts of the Colorado in an effort to stabilize the shorelines.

    They also consume a phenomenal amount of water each day (I forget the exact figure, but it may be ten times the fastest rate of our domestic or native varieties). As with all exotics, which are lacking a natural ‘predator’ to control the population, the tamarisk quickly wiped out native species, and efforts to control or eradicate the infestation have not been successful. Our guide commented that the reductions in the flow of the Colorado/Green/Yampa systems finds a significant part of the cause as the tamarisk itself.

    I’m certainly not opposed to making an effort to stabilize the banks of the Colorado drainage, but from what the guide was telling us, it sounds like it was a great idea that did not take into account the ‘unintended consequences’ of introducing a non-native species into the area.

    Where I live (Wyoming), it is illegal to bring a tamarisk into the county in which I reside, because they are ‘water-hogs’, and we have enough issues trying to keep enough water for the people, let alone some invasive species. If anyone is able to supply any additional information, such as who the ‘usual gang of suspects’ is (i.e., those who instigated this exotic species idea along the Colorado), I know I’d appreciate it.

    My sincere regards to all,

    The Most Deplorable and Mostest Despicable Vlad the Impaler

      • But cottonwoods don’t spread like tamarisk. Once established, tamarisk drives out the native willows and forms a nearly impenetrable wall along a river bank.

    • Interesting point, many wildlife refuges have been trying to eradicate these, often called salt cedar because they are alkaline and salt tolerant, for this reason. They also seem to provide erosion protection along some estuaries and sometimes are used as a excuse to install bulkheads. However, they were also considered valuable for shade and windbreaks which you might expect to slow evaporation. Native cedars (actually junipers) in the Texas Hill Country have had a similar reputation producing similar eradication attempts. Read something recently questioning this. The water they all consume has to be accounted for.

      For some time we have had an “exotics are bad” program which has made impartial analysis difficult. While they can cause serious problems, if you want to get in trouble ask how you identify an exotic if you did not know where it came from in the first place.

      • H. D. Hoese and tty:

        Thanks for the info. It always helps to have complete information!

        Vlad

    • Tamarisk is also called “salt cedar” and thrives along streams degraded by agriculture. It de-salinates the soil. Clean the stream and restore the flood cycle and Cottonwoods dominate, with tamarisk as understory. Tamarisk, along with other so-called “invasive species” such as arundo donax, has been transformed into yet another environmentalist guilt trip whose decimation provides profitable employment for government rent seekers.

      scientists “rationalized scapegoating of Tamarix as an agent of change because of its ability to thrive in anthropogenic habitats.”

      The Thirsty Tree
      http://www.terrain.org/articles/27/lamberton.htm

      Is it coincidence that the self-righteous haters of foreign flora are typically Climatastrophists?

  33. When this year resembles 1983 and Powell and Mead fill up he’ll look even more foolish.
    Snow pack and flows are looking like it may happen.

    Looks to me like Wettest may soon be reality in all of the West with a likely cyclical return to the same kind of wet years of the 70s to the 90s.
    And it’s not just the west coast. Inland upstream water basins are way up and feeding Lakes Powell and Mead in ways that may fill both as was the case in that earlier era.
    As sure as the Texas drought ended so is the rest of the west coast drought.
    https://www.wired.com/2015/05/texas-floods-big-ended-states-drought/

    http://www.sacbee.com/news/state/california/water-and-drought/article126087609.html
    “When the snowpack is way above normal and the Sierra Nevada precipitation index is above ‘82-’83, it’s time,” he said. Northern California has received so much rain this year that the region is on pace to surpass the record rainfalls of 1982-83.

    http://lakepowell.water-data.com/

    Rivers feeding Lake Powell are running at 149.52% of the Feb 22 avg. Click for Details

    http://lakemead.water-data.com/

    https://en.wikipedia.org/wiki/Lake_Mead
    Multiple wet years from the 1970s to the 1990s filled both lakes to capacity,[10][11] reaching a record high of 1225 feet in the summer of 1983.[11] In these decades prior to 2000, Glen Canyon Dam frequently released more than the required 8.23 million acre feet (10.15 km3) to Lake Mead each year, allowing Lake Mead to maintain a high water level despite releasing significantly more water than for which it is contracted.

  34. Definitely cherry-picking the natural variation in precipitation. If the proxies for moisture in the watershed are anywhere near accurate, the area is prone to long term droughts and floods, and the 20th Century was a relatively wet period. So if CO2 is the cause, where was the CO2 coming from before the Industrial Revolution?

  35. Warming in the 21st century reduced Colorado River flows by at least 0.5 million acre-feet…

    Bradley Udall of CSU, are you unaware that Colorado River Water helps keeps your campus nice and green?

    Utilities from across the East Slope transfer about 475,000 acre-feet of water from the Colorado River basin to the East Slope each year. On average, Denver Water customers use about 125,000 acre-feet of West Slope water per year.
     — http://www.denverwater.org/SupplyPlanning/WaterRights/

    More than half of Fort Collins water is diverted from the Colorado River.

    Approximately 40% of Fort Collins water is used for landscaping.

    Bradley Udall, put that water back where it belongs!

  36. The team began its investigation because Udall learned that recent Colorado flows were lower than managers expected given the amount of precipitation.

    So the conclusion is that all the lacked water is vapored due high temperature?
    Sorry. I’ve no time to verified such a conclusion, but where can I go to see the data?

    • I seem to remember that it has been somewhat dry, and that groundwater levels are low. This means that flow will be less than normal for a given amout of precipitation since more water soaks into the ground.

  37. This means that flow will be less than normal for a given amout of precipitation since more water soaks into the ground.

    This is not what they claim.

    Water loss increases as temperatures rise because plants use more water, and higher temperatures increase evaporative loss from the soil and from the water surface and lengthen the growing season.

    So the complete scenario is: High temperature increase vapor + plants need more water from soil and then it suck more water from the river?

  38. Just in case it comes as a shock to anybody here, southwest Arizona and southeast California really are in a state of permanent drought. After all, those regions are low altitude deserts. In fact, El Centro is as much as 61 feet below sea level and the highways get down to 300 feet below it as you travel toward the Salton Sea.

    The real reasons for a drop in river levels south of Hoover dam are huge population growth along the river and increased agriculture. The population of Yuma in 1975 was just over 32,000. Today it is over 130,000 and growing yearly. Yuma County-wide there are somewhere near 250,000 water using residents.

    As an avid follower of the weather in this region I can say that, if anything, high temperatures have declined here since I moved here in 1989. El Niño events have caused an increase in precipitation in our region during the same period to the extent that it is as green as grass in late summer here. In fact, nearby low hills north of Yuma get covered in grass from time to time during the year.

    • My understanding of the late summer rains is the monsoon season that is a constant in the US Southwest.

      But your right of course, the area is essentially a large desert for a good reason – the persistent lack of rainfall. So what else is new.

    • Interesting satellite view of Yuma. Where DID all that green come from? Multiply this explosion of agricultural use by the dozens of cities and thousands of massive farms that flank the Colorado River all the way to Mexico, and it’s no real surprise that river drainage is declining each year.

      Gaww! I wonder how quickly Dr. Overpeck can make this year’s record 13 million acre-feet inflow into Lake Powell disappear? That, boys and girls, is the highest inflow to Mead in the last 50 years, excepting a few years in the 80’s!

      It’s easy to see by the spread of green from satellite imagery where most of the water is going: 90% of the water used in Colorado is for growing stuff; Arizona uses 85% (mainly Colorado River water) … and so it goes throughout the arid West, from its northernmost drainages and tributaries, like Wyoming’s Green, on down the Colorado River Basin, and far out into its hundreds of water-scarce settlements along its diversions. The Colorado hasn’t run its course to the Gulf since the 60’s, and every year its progress is foreshortened by new crop-plantings… all to the ubiquitous susurration of mammoth farm irrigation sprinklers.

      • the highest inflow to Mead in the last 50 years… Make that “the highest inflow to Lake Powell in the last 50 years”

  39. In a similar vein, the Sunday NYT had an extensive story about Mexico City and its climate-related problems. The city has millions and millions of people and an extremely limited and uncertain water supply. The city is sinking due to groundwater pumping, and millions of residents relying on water tanker trucks to deliver water to their homes. The outdated sewer system is overwhelmed.

    The article’s author places a good part of the problem on climate change, but the overall discussion supports the view that most of the problem is due to explosive population growth on top of water shortages that have been the rule for decades.

    Climate change would appear to have little to do with their ills, but public officials blame cc as an apparent excuse not to make major improvements – i.e. we’re all gonna die anyway so why spend money. There’s some discussion of temperatures going up “several degrees” in this century and the usual drought predictions.

    This story is vintage NYT, with otherwise good reporting tainted by the de rigeur armageddon cc scenario. Chief among the inevitable consequences is international destabilization due to the flight of millions of climate refugees.

  40. “From 2000-2014, the river’s flows declined to only 81 percent of the 20th-century average ….” Is this data utilized with respect to the paper conclusions?

    If so, how do things change with respect to 2000-2016 data?

    Do the authors care?

  41. No one ever wants to hear that the correct answer is “no one knows.”

    “…I see how they get their information and I can’t believe that they know it…”

  42. So build some nuclear power stations on the coast and put in desalination plants for the unnaturally unsupportable population of the Californian Desert. Stop damming the Colorado River and losing water into the soft sandstone , and abstracting water from where it was never meant to be taken from to water the unsupportable hence artificial and ecologicaly unsustainable population of LA and Las Vegas, for example. The LA Viaduct and the draining of the Owen’s Valley is a Sierra long obscentity, unrecognised by the SIerra club, of course, who would rather suck everywhere dry while closing Diablo Canyon on utterly spurious grounds. Not that we in the UK know anything about California, of course. Just more than most Californians appear to.

  43. That’s America :

    “This paper is the first to show the large role that warming temperatures are playing in reducing the flows of the Colorado River,” said Overpeck, UA Regents’ Professor of Geosciences and of Hydrology and Atmospheric Sciences and director of the UA Institute of the Environment.”

    and that’s what it is:

    https://www.google.at/search?q=amerikam%C3%BCde&client=ms-android-samsung&prmd=imvn&lr=lang_en&sa=X&ved=0ahUKEwjp1bfm3KTSAhXJiywKHRTeBWUQuAEIFg&biw=360&bih=559

  44. It is simply false that the Colorado River basin has been in a drought since 2000. We have probable had at least two dry periods and two wet periods during that time. If I remember correctly, Lake Powell water levels rose faster than anytime in history during the spring run-off season a few years ago. This year (2016 – 2017) snow season finds all of the drainages in the state, including the Colorado River drainage at nearly 200% of average for this time of the winter. I stopped reading the paper when I got to the part ‘what the models show’ . A habit I developed a few years ago, saves a lot of brain pain.

  45. If higher flow was concidered a concern, i am certain he would predict higher flow in a warmer climate.
    Find anything that may be harmfull in some circumstances, then a climateer will predict that exacly this will happen because of climate change.
    Have you ever heard a climateer say that some conditions could improve because of climate change?
    These peoble are conservatives to the bones. Every change will make all worse than it was. The earth should be as they remember it from childhood. Every change is a threat, because they can not predict the outcome, even if they say they have that skill.

  46. Udall said, “A megadrought in this century will throw all our operating rules out the window.”

    Maybe the operating rules for Oroville Dam had concluded that spillway maintenance was unnecessary, due to the assumption of a permanent megadrought in the area. Oops.

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