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 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.”
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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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One acre-foot will serve a family of four for a year…yeah, but where they gonna’ put it?
From my two winter visits to Phoenix much of it is stored in swimming pools and waterholes on golf courses.
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.
“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.
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.
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.
Being right for the wrong reason doesn’t count.
The ag and population are mainly downstream anyway.
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.
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.”
So when we cool, flows are reduced. And when we warm flows are reduced. OKEE DOKEE!
When nothing happens, flows are reduced.
When flows increase, flows are reduced.
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?
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.
This translates to 2.9×14 is 40.6 million acre-feet in 14 years.
This means 0.5 million acre-feet in 14 years.
Which one is correct ?
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.
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….
whoops, 17 reservoirs and 17 diversions.
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.
Edit
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
Actually the native cottonwood is almost as bad a ‘water-hog’ as the tamarisk.
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.
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?
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.
This one is fun too. (You can click on the triangles for more data.)
https://www.cbrfc.noaa.gov/lmap/lmap.php?interface=esp
Sorry, I thought the picture would show. That link is to a map of the Colorado watershed with indications of expected river flow. A LOT of blue triangles indicating over 130% of average. Would be interested to know just how much over average this year is likely to be. 130% is the top of the scale…
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?
Bradley Udall of CSU, are you unaware that Colorado River Water helps keeps your campus nice and green?
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!
Upper Colorado Basin snowpack is already at 104% compared to the average peak snowpack date of April 15. All the western drainage basins are quite full, in the warmest year evah!
http://snowpack.water-data.com/uppercolorado/index.php?getall=1
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.
This is not what they claim.
So the complete scenario is: High temperature increase vapor + plants need more water from soil and then it suck more water from the river?
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”
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.
15 years of river flows tells us nothing about future river flows.
“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?