Readers may recall that Dr. John Christy found that irrigation increases temperatures measured in the central valley. This study finds it also increases rainfall and storms due to the additional available moisture. CO2 is not listed as being part of the equation, which makes the ‘extreme weather’ meme being pushed by alarmists even less likely. – Anthony
Central Valley irrigation intensifies rainfall, storms across the Southwest
UCI study finds that doubling of moisture in air has positive, negative effects
Irvine, Calif., Jan. 28, 2013 – Agricultural irrigation in California’s Central Valley doubles the amount of water vapor pumped into the atmosphere, ratcheting up rainfall and powerful monsoons across the interior Southwest, according to a new study by UC Irvine scientists.
Moisture on the vast farm fields evaporates, is blown over the Sierra Nevada and dumps 15 percent more than average summer rain in numerous other states. Runoff to the Colorado River increases by 28 percent, and the Four Corners region experiences a 56 percent boost in runoff. While the additional water supply can be a good thing, the transport pattern also accelerates the severity of monsoons and other potentially destructive seasonal weather events.
“If we stop irrigating in the Valley, we’ll see a decrease in stream flow in the Colorado River basin,” said climate hydrologist Jay Famiglietti, senior author on the paper, which will be published online Tuesday, Jan. 29, in the journal Geophysical Research Letters. The basin provides water for about 35 million people, including those in Los Angeles, Las Vegas and Phoenix. But the extra water vapor also accelerates normal atmospheric circulation, he said, “firing up” the annual storm cycle and drawing in more water vapor from the Gulf of Mexico as well as the Central Valley.
When the additional waves of moisture bump into developing monsoons, Famiglietti said, “it’s like throwing fuel on a fire.”
Famiglietti, an Earth system science professor in the School of Physical Sciences, and colleague Min-Hui Lo, a postdoctoral researcher at the University of California Center for Hydrologic Modeling who is now at National Taiwan University, painstakingly entered regional irrigation levels into global rainfall and weather models and traced the patterns.
“All percent differences in the paper are the differences between applying irrigation to the Central Valley and not applying it,” Famiglietti said. “That’s the point of the study – and the beauty of using computer models. You can isolate the phenomenon that you wish to explore, in this case, irrigation versus no irrigation.”
Famiglietti’s team plans to increase the scope of the work to track how major human water usage elsewhere in the world affects neighboring areas too. A better understanding of irrigation’s impact on the changing climate and water availability could improve resource management in parched or flooded areas.
About the University of California, Irvine: Founded in 1965, UCI is a top-ranked university dedicated to research, scholarship and community service. Led by Chancellor Michael Drake since 2005, UCI is among the most dynamic campuses in the University of California system, with more than 28,000 undergraduate and graduate students, 1,100 faculty and 9,400 staff. Orange County’s second-largest employer, UCI contributes an annual economic impact of $4.3 billion. For more UCI news, visit news.uci.edu.
Source: http://news.uci.edu/press-releases/central-valley-irrigation-intensifies-rainfall-storms-across-the-southwest-2/
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philjourdan says:
January 29, 2013 at 9:40 am
Phil,
Less and less water is coming from the Colorado River into California. Historically, California used water that was actually claimed by Arizona. It has only been in the past few decades that Arizona has been able to make use of their share of the water.
Most of the irrigation in the San Joaquin Valley comes from reservoirs found in the Sierra Nevada mountains, mostly from Fresno north. There are two giant canals that suck water from the rivers and reservoirs in the north state and pump the water to the south. The Delta-Mendota canal is specifically for irrigation and terminates just west of Fresno. The California Aqueduct transports water from as far north as Oroville dam to areas south and east of Los Angeles.
So the net effect, if this study is in any way accurate, is to take Northern California rainfall and, in a very circuitous manner, deliver more rainfall to the Great Basin and the southwest deserts.
We often get remnants of the summer monsoons that hit Arizona and adjacent states clear up here in Idaho. By the time they reach us, the moisture is pretty much spent, but I’ve seen “monsoon rainfall” in Idaho. (We’re happy to get it whatever the source.)
groundbreaking….Arctic Oscillation, Pineapple Express
Re: the topic in hand. I would have thought one would need very large swathes of irrigated land to enable a significant evapo-transpiration effect. I was watching something the other day about the local climate (lake snowfalls?) due to the Great Lakes, and thats all water! I can imagine there are some effects, but given that irrigation has been a human ‘thing’ for many centuries, I don’t think we can call it significant compared to oceanic or natural lake evaporation?
@Anthony – re Ms Ravasio – IIRC, I’m fairly sure that I (and others) said in the very first thread she was posting in, that she was obviously only here to ‘troll’ even after we had welcomed her and tried to be helpful! FWIW – I think you (and us) have been too generous! just my view…
It’s probably a viable first approximation. A more refined analysis would probably show the sum total of irrigated areas throughout the SW are a key causal factor. However the Central Valley is a huge chunk of SW irrigated land.
“All percent differences in the paper are the differences between applying irrigation to the Central Valley and not applying it,” Famiglietti said. “That’s the point of the study – and the beauty of using computer models. You can isolate the phenomenon that you wish to explore, in this case, irrigation versus no irrigation.”
No data… just models!
[Reply: Use angle brackets. — mod.]
May I suggest those who doesn’t belive in problems caused by irrigation, and for that other causes of erosion due to changes in microtopical biotops without first analysing the ground, to go to the Library. Recommended book Haggett, Peter; Geography a Modern Synthesis, Harper International 1983. Might be a bit old, but it takes care of all questions a scholar or a teacher might need to know in order to analyse and/or teach others!
philjourdan: … the Imperial valley…is irrigated through a series of canals, fed by – the Colorado River.
You are certainly correct here. And the All American Canal gets its cut after the Colorado Aqueduct has already diverted substantial amounts to our coastal cities. But the Imperial Valley is well removed from and has no connection with the San Juaquin (Central) Valley which is the subject of the post.
Actually the Imperial Valley is almost entirely below sea level and was covered with the waters of Lake Cahuilla just a few hundred years ago. Here’s the link again from my comment above:
http://www.sci.sdsu.edu/salton/AncientLakeCahuilla.html
@juanslayton – I read your link. Fascinating. I was aware of the pre-historic lake (as most residents are), but not all the eye witness (many times removed) accounts of it. It is indeed mostly under sea level, as you can ride around and see marks high up on towers with the label “Sea Level”.
My problem was in the nomenclature. I guess technically, the Imperial Valley is the imperial valley and not the “central valley” but the folks down there call it the central valley as well. However, the authors probably were referring to the “official” central valley, so that clears up my confusion.
Thanks for the link and the correction.
Jackson was right, it’s a poor mind can think of but one way to spell a word. But “San Joaquin” will satisfy the spelling police (not San Juaquin).
Believe it or not but there is much water going into the atmosphere in WA, OR, and ID. Once mostly flood-irrigation, there is a great amount of investment in center pivot systems. The former lost water to depths beyond the root zone while the new systems spray water, thus adding directly to atmospheric humidity (evaporation) and indirectly (photosynthesis).
Images:
http://industrial-landscape.com/FG-image-gallery/source/image/plymouth_wa_center_pivot.jpg
Coordinates from Google Earth for WA along the Columbia River:
46.3075, -119.0191 Zoom out, slowly; note circles. Near Kennewick.
47.1603, -119.9446 Wine grapes; much land in this area is still rill irrigated.
Just south of these vines is the “Ancient Lakes” area, a result of the Ice Age Floods and a western part of the ‘Channeled Scablands”.
its like complaining about the farmer that feeds the entire village, but whose fields draw a few birds and rats and their subsequent droppings.
“We could get rid of these here droppings if we just shut this d@mn farmer down and run him outta town”
philjourdan says:
January 29, 2013 at 9:40 am
****
Yet, at least in the southern Valley, virtually all the water comes from the Colorado river Basin (I am unfamiliar with the northern and mid central valley water sources). …
This is totally, completely, unequivocally wrong – pure, unadulterated baloney in fact. There is no Colorado River water used in any part of the Great Valley. That would require pumping water from the Colorado, across the Mojave Desert northward and over the Tehachapi Range or Southern Sierra Nevada to be used. That simply doesn’t happen, nor are there any infrastructural systems in place that could make it happen. Water in the Great Valley moves from Northern California southward, running in two majors canals from the Sacramento-San Joaquin Delta along the west side of the San Joaquin Valley until it reaches pumping stations just west of I-5, where it is then shipped south for use in L.A. swimming pools. This one of the major reasons that Northern Californian’s keep hoping that So. Cal. will slide off the state and into the Pacific.
Colorado water IS used in the Imperial Valley, and urban areas along the Southern California coast. I’m not sure, but I believe that the urban use of Colorado water is from Orange southward, or south of Orange. L.A. and points north grab water off the Central Valley and Owen’s Valley projects.
@Duster – You probably should have read the entire comments before posting yours. The issue was resolved as a simple misunderstanding of the nomenclature. The Colorado does indeed irrigate the central valley, just not THE Central Valley. As Juan Slayton pointed out, I was talking about the Imperial valley (the southern part of the California central interior, and a valley), while the authors were talking about the northern stretch.
My comment was not wrong. My nomenclature was.
This appears to be the biotic pump in action.
Generally the biotic pump is associated with forests “pumping” moisture perhaps 1000’s of kilometres inland, or the reverse where deforestation along coastal areas stops that moisture reaching inland thus changing the regional climate. It is thought such effect began to first have a noticeable effect historically when the large scale building of wooden boats began.
Anthony Thank you, just spent 45 minutes reading reference mentioned by buckyworld. Patricia has so missrepresented this report, It was written 2000-2001 and the 1981 climate change reference could only have been global cooling. Thank you for keeping the less than honest off WUWT. chuck
So Death Valley won’t be if we keep this up?
The south west of Western Australia is in a similar situation. Half the Perth water supply is used for irrigation (almost all residential), plus there are 60,000 irrigation wells.
We have nothing like the Sierra Nevada, but if this paper is correct we should see increased rainfall inland and down wind from Perth. We don’t. Rainfall has decreased in these areas over the last 60 years (a period during which Perth roughly tripled in size). But rainfall has increased substantially in the monsoon zone which starts about 500 Kms north east of here.
My interpretation is Perth irrigation has no effect on inland rainfall and the increase in monsoon rains is due to shifts in climatic patterns. I suspect the same is true for the US southwest.
http://www.clw.csiro.au/publications/waterforahealthycountry/swsy/pdf/Effect_of_climate_change_on_SWWA_hydrology.pdf
Um, we irrigate during the summer when it doesn’t rain… So that evaporated water just blows away. Are they asserting that it causes a bit more rain in the desert in the summer? (most everything down wind of us is desert. Nevada, Arizona, etc.)
So cooling and making bloom the Great (Central) Valley, and adding a tiny amount of summer water to the deserts of the Western States is somehow bad? I can think of no way at all that it can be anything but spectacularly good. We’re talking places that get less rain in a year than most of the nation gets in a month. Add 20% to that (an outrageous overstatement) and folks would still be in a desert.
So I have no doubt that irrigation puts more water in the air, that must come out as precipitation somewhere. Just not seeing how that will in any way be a problem given California and the Western States being so dry to start with.
Brief Geography Lesson:
California has a Great Valley, often called the Central Valley, that reaches from ‘near’ Oregon down to about 2/3 of the way to Mexico. The State Capital of Sacramento is in the middle of it, about the same latitude as San Francisco. From Sacramento north is named The Sacramento Valley. From Sacramento south is called the San Joaquin Valley. (Each named for the main river down the middle of them). That, together, is one giant drainage basin for the Sierra Nevada mountains to the East, the Cascades to the North and the side of the Tehachapi mountains in the south end that faces north. On the OTHER side of the Tehachapi mountains faces toward the Los Angeles basin. See map here:
The California Aqueduct sucks up enormous quantities of water from the Sacramento Valley and ships it south to the Los Angeles basin Along the way a lot slops out in the deserts of Kern County and related areas in the more southerly parts of the San Joaquin Valley (used to grow things like cotton. A very water intensive crop. In a desert….)
The Imperial Valley is ‘way south’ of Los Angeles. It is basically on the Mexican Border. Colorado River water naturally goes there. In fact, it made the Salton Sea (after a bit of an oppsy with a canal sprung a big leak…)
No Colorado River water goes to the Great (Central) Valley. We export water south…
Anything that causes more water to fall as rain anywhere in the dry Western States is a welcome help.
Speaking of “Exteme Weather”, last weekend was the 35th anniversay of “The Blizzard of ’78” in the Midwest.
http://www.erh.noaa.gov/iln/research/Blizzard1978/blizzard78.php
I lived in west-central Ohio at the time, a little over an hour north of Dayton. We got more snow that Dayton did. The pictures don’t do it justice. I think most were taken after the roads were cleared. Where I was it took a backhoe and a city-type plow 8 hours to make it a quarter mile down a local road.
(Did we have “Global Warming” back then?)
Thinking about how the monsoon process works, I think irrigation does contribute to monsoon rainfall but not directly (primarily) as the authors assume.
Monsoons are driven by near surface heat that drives convection, which in turn pulls in moist tropical air on near continental scales.
Increase atmospheric water vapour and you get an increased greenhouse effect, warmer near surface temperatures and increased convection, and more tropical air drawn in, faster. Which would be the main cause of increased monsoonal rainfall. Although the WV from irrigation would make a contribution.
Gunga Din says:
January 29, 2013 at 2:10 pm
“Speaking of “Exteme Weather”, last weekend was the 35th anniversay of “The Blizzard of ’78″ in the Midwest.
(Did we have “Global Warming” back then?)”
Yes, indeed. “Global Warming” began on January 29th, 1976 at 10:30 A. M.. I thought everybody knew this.
If these are primarily conclusions based on computer modelling then they are hypothesis and not direct observation. Experience dictates that the conclusions could be as much a product of the assumptions and calculations built into the model as of any real world phenomenon. Confirmation will require real world data.
Ok so for weeks now we have been arguing that there is no statistical increase in “extreme weather” now there is and it’s caused by irrigation – whichissit? I know this is somewhat localised but we can’t have our cake and eat it unless we bake an extra cake labelled “regional (local?) weather phenomenon, in which case this is not about global climate.
This doesn’t make sense: water is well-known moderator of temperatures. Irrigation should result in fewer extremes. What gives?
Oh, groan. Computer models again. Can we PLEASE get back to SCIENCE (experiments and observations) to determine the way things work?
@John Hultquist
That would be Zulu time, right?
juanslayton says:
“That would be Zulu time, right?”
Details. But, yes. Reminds me of a fellow looking for a weather station with Lat./Long. coordinates in the middle of a water body. Minor detail!