Guest essay by Larry Hamlin
The Orange County Register published a prior Denver Post article claiming that “climate change warming” had caused a 20% reduction in Colorado River flow since 1900 as shown below.
The Denver Post article (as published in the Orange County Register) notes:
“First, the river is drying as the West becomes warmer and more arid. Warmer temperatures speed evaporation, further reducing a lack of water from less precipitation. One report by the U.S. Geological Survey found the Colorado River’s flows have dropped by 20% since 1900 primarily due to warming.”
The U.S. Geological Survey report referenced in the Denver Post article then references a February 2020 study “recently published in Science” which notes:
“The sensitivity of river discharge to climate-system warming is highly uncertain, and the processes that govern river discharge are poorly understood, which impedes climate-change adaptation.”
“A Monte Carlo simulation with a radiation-aware hydrologic model resolves the longstanding, wide disparity in sensitivity estimates and reveals the controlling physical processes.”
This computer model simulation is then used to “estimate” the following outcome for Colorado River flows as:
“We estimate that annual mean discharge has been decreasing by 9.3% per degree Celsius of warming because of increased evapotranspiration, mainly driven by snow loss and a consequent decrease in reflection of solar radiation.”
Thus, the claim that “the Colorado River flows have dropped by 20% since 1900 primarily due to warming” is driven by a “computer model simulation” which was intended to reveal the “controlling physical processes” regarding Colorado River flows into Lake Mead.
The Denver Post article never addresses any measured data regarding Colorado River flows into Lake Mead with this data readily available from the U.S. Bureau of Reclamation covering the period from 1930-2019.
Additionally, neither data of the Upper Colorado River Basin Snowpack levels during this same period that feed the Colorado River nor data of the changing supply and demands from the Colorado River water’s many users during this period is addressed in the Denver Post article.
The peer review “study” published in Science assumes the lower levels of Lake Mead are caused by reduced flows from the Colorado River and then uses a “Monte Carlo simulation” computer model to determine how “climate change warming” caused this reduced flow of the Colorado that resulted in lower water levels in Lake Mead.
Climate scientist Dr. Roy Spencer evaluated measurement records of inflows of the Colorado River at Lees Ferry starting in the 1930s as well as measurements of snow levels at the upper Colorado basis over this period which is the primary source supplying Colorado River flows arriving at Lees Ferry.
Dr. Spencer’s study and analysis of measured data regarding the Lake Mead Elevation changes since 1940 and the Colorado inflows since 1930 is shown below.
Key highlights from the study are noted as:
- Contrary to claims that drought is causing Lake Mead water levels to fall, the Colorado River natural flows into Lake Mead show no long-term trend since 1930.
- Decadal time scale variations in river flow do occur, though, related to the Pacific Decadal Oscillation (PDO).
- Since about 2000, use of Lake Mead water has exceeded river inflow, causing water levels to drop. The negative phase of the PDO since that time has exacerbated the problem.
Data from the U.S. Bureau of Reclamation (USBR) establish that there has been no long term-term trend in the natural Colorado River flow into Lake Mead as shown in detail below from Figure 1 of Dr. Spencer’s study.
Data from snowmelt in the Upper Colorado River Basin Snowpack that feeds the water entering Lake Mead is shown below in Figure 3 of Dr. Spencer’s study which shows there is no long-term trend in snowpack measurements in the period 1938-2022.
Dr. Spencer’s study addresses the declining water levels of Lake Mead since about year 2000 by establishing that downstream water user demands have significantly exceeded water input into the lake as shown in Figure 2 below from a Bureau of Reclamation study published in 2012 that identified this excessive Colorado River water demand problem issue.
Dr. Spencer’s study addresses the impact of naturally occurring climate behaviors such as the Pacific Decadal Oscillation as contributing to changes that affect weather patterns over the Northeast Pacific which ultimately impact the long-term Colorado River snowpack levels of this region.
The conclusions form Dr. Spencer’s study are noted as follows:
“The popular narrative that drought due to climate change is causing Lake Mead to have less water available to it is incorrect. Since 1930, there has been no long-term change in the Colorado River flow upstream of what is now Lake Mead.
The latest climate models do not even predict a reduction in precipitation in the upper Colorado River watershed. (Dr. Spencer utilizes CMIP6 model predicted average yearly precipitation 1930-2050 over an area approximating the upper Colorado River watershed to establish this finding)
Multi-decadal changes in river flow do occur, though, and are related to the Pacific Decadal Oscillation, a natural fluctuation in weather patterns over the northeast Pacific. Recent record-low water levels in Lake Mead are primarily due to record high water demand from the lake, since approximately 2000. The problem is being made somewhat worse by the negative phase of the PDO, also since approximately 2000.”
The Denver Post article’s claim of “climate change warming” impacts being responsible for the declining water levels of Lake Mead as determined by a “computer model simulation” are unsupported and completely contradicted by readily available measures of Upper Colorado River Basis snow levels and USBR water inflow data for the Colorado River flowing into Lake Mead.
Colorado River Flow Data Disproves “Climate Change Warming” Computer Model Flow Reduction Claims
Guest essay by Larry Hamlin
The Orange County Register published a prior Denver Post article claiming that “climate change warming” had caused a 20% reduction in Colorado River flow since 1900 as shown below.
The Denver Post article (as published in the Orange County Register) notes:
“First, the river is drying as the West becomes warmer and more arid. Warmer temperatures speed evaporation, further reducing a lack of water from less precipitation. One report by the U.S. Geological Survey found the Colorado River’s flows have dropped by 20% since 1900 primarily due to warming.”
The U.S. Geological Survey report referenced in the Denver Post article then references a February 2020 study “recently published in Science” which notes:
“The sensitivity of river discharge to climate-system warming is highly uncertain, and the processes that govern river discharge are poorly understood, which impedes climate-change adaptation.”
“A Monte Carlo simulation with a radiation-aware hydrologic model resolves the longstanding, wide disparity in sensitivity estimates and reveals the controlling physical processes.”
This computer model simulation is then used to “estimate” the following outcome for Colorado River flows as:
“We estimate that annual mean discharge has been decreasing by 9.3% per degree Celsius of warming because of increased evapotranspiration, mainly driven by snow loss and a consequent decrease in reflection of solar radiation.”
Thus, the claim that “the Colorado River flows have dropped by 20% since 1900 primarily due to warming” is driven by a “computer model simulation” which was intended to reveal the “controlling physical processes” regarding Colorado River flows into Lake Mead.
The Denver Post article never addresses any measured data regarding Colorado River flows into Lake Mead with this data readily available from the U.S. Bureau of Reclamation covering the period from 1930-2019.
Additionally, neither data of the Upper Colorado River Basin Snowpack levels during this same period that feed the Colorado River nor data of the changing supply and demands from the Colorado River water’s many users during this period is addressed in the Denver Post article.
The peer review “study” published in Science assumes the lower levels of Lake Mead are caused by reduced flows from the Colorado River and then uses a “Monte Carlo simulation” computer model to determine how “climate change warming” caused this reduced flow of the Colorado that resulted in lower water levels in Lake Mead.
Climate scientist Dr. Roy Spencer evaluated measurement records of inflows of the Colorado River at Lees Ferry starting in the 1930s as well as measurements of snow levels at the upper Colorado basis over this period which is the primary source supplying Colorado River flows arriving at Lees Ferry.
Dr. Spencer’s study and analysis of measured data regarding the Lake Mead Elevation changes since 1940 and the Colorado inflows since 1930 is shown below.
Key highlights from the study are noted as:
- Contrary to claims that drought is causing Lake Mead water levels to fall, the Colorado River natural flows into Lake Mead show no long-term trend since 1930.
- Decadal time scale variations in river flow do occur, though, related to the Pacific Decadal Oscillation (PDO).
- Since about 2000, use of Lake Mead water has exceeded river inflow, causing water levels to drop. The negative phase of the PDO since that time has exacerbated the problem.
Data from the U.S. Bureau of Reclamation (USBR) establish that there has been no long term-term trend in the natural Colorado River flow into Lake Mead as shown in detail below from Figure 1 of Dr. Spencer’s study.
Data from snowmelt in the Upper Colorado River Basin Snowpack that feeds the water entering Lake Mead is shown below in Figure 3 of Dr. Spencer’s study which shows there is no long-term trend in snowpack measurements in the period 1938-2022.
Dr. Spencer’s study addresses the declining water levels of Lake Mead since about year 2000 by establishing that downstream water user demands have significantly exceeded water input into the lake as shown in Figure 2 below from a Bureau of Reclamation study published in 2012 that identified this excessive Colorado River water demand problem issue.
Dr. Spencer’s study addresses the impact of naturally occurring climate behaviors such as the Pacific Decadal Oscillation as contributing to changes that affect weather patterns over the Northeast Pacific which ultimately impact the long-term Colorado River snowpack levels of this region.
The conclusions form Dr. Spencer’s study are noted as follows:
“The popular narrative that drought due to climate change is causing Lake Mead to have less water available to it is incorrect. Since 1930, there has been no long-term change in the Colorado River flow upstream of what is now Lake Mead.
The latest climate models do not even predict a reduction in precipitation in the upper Colorado River watershed. (Dr. Spencer utilizes CMIP6 model predicted average yearly precipitation 1930-2050 over an area approximating the upper Colorado River watershed to establish this finding)
Multi-decadal changes in river flow do occur, though, and are related to the Pacific Decadal Oscillation, a natural fluctuation in weather patterns over the northeast Pacific. Recent record-low water levels in Lake Mead are primarily due to record high water demand from the lake, since approximately 2000. The problem is being made somewhat worse by the negative phase of the PDO, also since approximately 2000.”
The Denver Post article’s claim of “climate change warming” impacts being responsible for the declining water levels of Lake Mead as determined by a “computer model simulation” are unsupported and completely contradicted by readily available measures of Upper Colorado River Basis snow levels and USBR water inflow data for the Colorado River flowing into Lake Mead.
I sorta think conscious or unconscious bias was present in the computer model. As the writer “knows” there is dread global warming, a result that agrees with that is “right”.
Who cares that the Colorado River is overallocated between the users?
In my part of Colorado (Boulder Front Range area), 2023 is the wettest in my recollection. The irrigation ditches are still running to some extent, although there was some freezing this past weekend. Typically, they dry up in July around here.
Clearly your observations are correct. We are using Colorado river water at a rate similar to the past but the levels remain constant. If we get snow fall like last year it will be a new ball game.
https://powell.uslakes.info/Level/
https://mead.uslakes.info/Level/
It’s been the same in Cheyenne. In June we had 12″ of rain, which is 5x times “normal,” if there even is such a thing as “normal”.
Funny. I looked up Boulder snowfall records, and 4 of the 10 highest snowfall years of the last 120 years were in the last decade. Must be the global warming; of which we evidently need more.
Interesting background fact. When the Colorado Compact water use agreement was set, it was based on past decades that were wetter than ‘normal’. That alone dooms it. Never mind the population explosion since in a known semiarid region.
The only question is, will Phoenix (at least it’s water thirsty golf courses) eventually go the way of Chaco Canyon or Mesa Verde? (Both Amerindian settlements were abandoned during the last SW megadrought, long before AGW became a factor.)
John Wesley Powell had the advantage of exploring before political correctness, and accurately blamed the cliff dwellings and their vacancy as due to the “prowess of the Navajos” who invaded from the north. If climate had anything to do with it most likely involved freezing these Athabaskans out of Canada.
Our local leftist papers have covered the Great Salt Lake’s decline a little more scientfically than this Colorado paper, generally blaming growing agriculture while acknowledging nearly constant precipitation.
Don’t worry, Rud. Water flows toward money.
Perhaps the Tom Nelson interview of Mike Wallace (https://www.youtube.com/watch?v=Hyi2wXUDpv0), and Wallace’s work on Western Streamflows (https://www.tandfonline.com/doi/full/10.1080/02626667.2019.1567925) provide some additional insight. From my worm’s eye view, Spencer and Wallace conclusions may be in agreement. At least, it seems to me that they might agree that the Register/Post’s article statement “the river is drying as the West becomes warmer and more arid. Warmer temperatures speed evaporation” is just not true.
For years I have assumed that the falling water flow is caused by more and more people living in the areas which use the Colorado as a source of domestic water supply.
Definitely. When the Anasazi suffered through their multi-century drought period, their population started out at something like less than 1% of today’s.
There has also most likely been considerable new agriculture developments since 1940 that use the water for irrigation. I suspect data is available to confirm or deny that hypothesis but my hunting for it won’t change anything.
AndyHce:
Yes, here in the Phoenix metropolitan area ~70% of our water is for agriculture,
22% residential, and 6% for industry [Examples: Intel has several Fabs, & Palo Verde nuke plant]. The golf courses are almost all fed by reclaimed water. Yet we could be more efficient like our neighbor Tucson which doesn’t allow grass on private property [only schools and parks]. Our water sources are ground water, lakes, & the Colorado River via the Central AZ Project: See http://www.cap-az.com
And to comment on pumped hydro as storage from a prior comment: our local power company [SRP] runs the 5 lakes to the east of Phoenix. They say our pumped hydro is maxed-out, so no further increase is likely.
The greatest use of water from Lakes Poweil and Mead is for electricity generation. Without that daily draw, managed to meet Southern California’s daily demand, there is more than enough storage to supply drinking and irrigation water.
Not so. The water used for generation is then used for irrigation downstream.
If your supposition was correct the outflow of the Colorado to Mexico would be much larger.
SO, the water can be used for more than one thing, it is not a zero sum game.
The daily outflow is reported at pretty high resolution
(at Page https://waterdata.usgs.gov/monitoring-location/09380000/#parameterCode=00065&period=P7D&showMedian=true
at below Hoover https://waterdata.usgs.gov/monitoring-location/09421500/#parameterCode=00065&period=P7D&showMedian=true)
Historically, water release goes up as the lake level goes down, due to reduced head pressure at the turbines. This is inconsistent with water conservation, but entirely consistint for dispatchable power to the grid.
Historically also, you can see where the growing seasons demand is low, the withdrawal for elecgtical load remains high.
The system is nearly at the maximum average daily discharge for multi-annual recharge.
Conservationists agree that the Colorado is overcommitted for the storage available. One of those commitments is a treaty with Mexico that guarantees a flow rate. So long as the flow continues at a rate that is equal to the average daily elecgtrical production, there is no problem. But if there was no electrical generation, the rate of flow to Mexico would remain the same. Unless the lakes are below “dead pool” Mexico will get the no less than the treaty obligation. Only in oversupply siturations at the dams will they get more.
Downstream of Hoover, the hourly flow rate can vary greatly, but the montly average flow remains the same.
The maximum demand for electricity in Southern California is during the summer months for air conditioning, when there is little precipitation upstream, and the mountain snow has already melted.
Water is necessary for both human life and plant life (for food), but it doesn’t burn very well, and it can only flow over a dam once.
So, in a dry climate, why not use something that does burn well, even if it’s non potable, to generate electricity? Like maybe oil or natural gas?
No arguement from me. But you may receive an argument from a pumped hydro evangelist.
Much (most?) of the water used by cities in the Colorado River watershed is returned via wastewater plants after treatment. The amounts taken for water plants and returned via wastewater plants would be metered. The amount returned should be subtracted from the amount taken.
(Of course the amount taken by California for cities like LA would not be returned.)
As a matter of fact, downscaled flobal climate models to regional projections (as here) perform very poorly irrespective of which regional downscaling technique is used. Covered in essay ‘Last Cup of Coffee’ in ebook Blowing Smoke.
Yes Rud, I miss the edit function as well.
We can never trust those flobal climate models.
he probably meant “flubal climate models”. 😎
flub
[ fluhb ]SHOW IPA
https://www.dictionary.com/0b29c1db2f0b1c9452c7.svg
See synonyms for: flubflubbedflubbing on Thesaurus.com
verb (used with or without object),flubbed, flub·bing.
noun
See the Mike Wallace (the live hydrologist, not the late CBS broadcaster) interview linked above. His paper seems to have survived peer review for some time, and he offers an opinion of climate modeling that doesn’t seem all that different from yours.
Look, you could go out and make a bunch of measurements. Or you could write a computer program. Now which of these gets funded?
It’s actually worse than you think. People are already making measurements. You can’t get funding to make more, that’s considered redundant. So either make a model, or look elsewhere for funding.
Only been 3 times to the Canyon and not since 2005 but every time it was indicated to us that the reduced flow through the Canyon and final outflow were because of peeple needing/wanting/taking more and more water, Klimut change was never mentioned, how things change when you have not been somewhere for a few years.
I was there recently and the same comment was made to me by a local guide.
So the people on the ground know more than the computer? What is this world coming to. Can’t trust models any longer.
Build a bunch of nuclear power plants to power desalination facilities. Modern SMRs are ideal to the task.
The solution is available but we, as a civilization, lack the will to do it.
There you go again, facts instead of feelings.
NO! James’ comment is based on feelings. There are no SMRs to deploy.
Where do they come up with this nonsense?
Everyone with an understanding of basic physical chemistry, as well as the geologic history of the planet knows that a warmer planet is a wetter planet … and conversely, a colder planet is a dryer planet. There is a fixed amount of water on the planet’s surface, mostly contained as liquid in the oceans … the warmer the ocean temperature, the higher the vapor pressure of water, thus the higher the relative humidity in the atmosphere. Plus the higher the air temperature, the higher the absolute water content of the atmosphere at any given relative humidity. And of course the world was far wetter, in terms of air humidity and vegetation density, in ancient times prior to the ice ages when the atmosphere was warmer.
Apparently these goombas think they can snooker the average non-scientifically educated civilian who incorrectly associates dry deserts with high temperatures, without also understanding that deserts are not hotter as a daily average than wet areas, and in fact swing very low in temperatures at night or in winter as compared to humid areas. Deserts are simply more subject to extreme diurnal and seasonal temperature swings, but are not hotter than humid areas.
In this day and age with the government’s attempts to manage misinformation, I would dearly like every paper, article, or news story that is based on a computer model to carry a disclaimer in the first sentence.
The premise of linking river flow to climate change is supported via application of NGSS (next generation science standards) which negates actual data in order to generate the desired results. Junk “ Science”!!!
It seems to me that the “all-time inflow” into Lake Powell is a bit better view and assessment of the Colorado River historical trend. https://graphs.water-data.com/lakepowell/
Click on selection “all time inflow”
Additionally illuminating is the historical record for air and water temperature at Lake Powell.
https://lakepowell.water-data.com/index2.php?as_of=2023-11-02 Select “Averages by calendar year”
There is essentially no change in water inflow, air temperature or water temperature in the records kept.
Certainly there is no AGW signal to be found. It can only be concocted.
AKA Finding AGW data where none exists.
The models got it wrong because they are the result of assumptions ofpeople that don’t know enough, at the key boards.
My goodness no! This was a horrid article, poorly put together and repetitively rambling.
All the information that one could possibly use, or need, appears on two graphs (that should have been one) and then, what, three thousand words saying the same thing over and over?
Boo!