From the University of California – Irvine and the “Environmentalists are never happy” department comes this amusing quandary.
The cause? Increased high-elevation plant growth fueled by climate warming
Irvine, Calif. — Freshwater runoff from the Sierra Nevada may decrease by as much as one-quarter by 2100 due to climate warming on the high slopes, according to scientists at UC Irvine and UC Merced.
Accelerated plant growth at higher elevations caused by increasing temperatures would trigger more water absorption and evaporation, accounting for the projected runoff declines, the researchers add.
A diminished river flow will only add to the burden of providing resources to the thirsty farms and homes that rely on it. The state is currently experiencing a severe drought, and some reservoirs and groundwater levels are at all-time lows.
The study findings appear this week in the early online edition of Proceedings of the National Academy of Sciences.
“Scientists have recognized for a while that something like this was possible, but no one had been able to quantify whether it could be a big effect,” said UCI professor of Earth system science Michael L. Goulden of the decreased runoff. “It’s clear that this could be a big effect of climate warming and that water managers need to recognize and plan for the possibility of increased water losses from forest evaporation.”
According to the researchers, runoff from mountain ranges is vulnerable to temperature hikes that lengthen growing seasons and result in more vegetation growth at high elevations. Snow-dominated mountain forests that are currently dormant in winter with cold temperatures have lower vegetative density and less evapotranspiration than downslope forests in the snow-rain transition zone, which have year-round growing seasons. Evapotranspiration is the combination of water evaporation from land and the loss of water through plant-leaf transpiration.
Goulden and UC Merced’s Roger C. Bales investigated the potential influence of a warming climate on evapotranspiration in the Kings River Basin in California’s Sierra Nevada and found resulting changes in the amount of freshwater mountain runoff available to serve surrounding communities.
They gauged water vapor emission rates and combined those measurements with remote sensing imagery to determine relationships among elevation, climate and evapotranspiration. According to the data, freshwater mountain runoff is highly sensitive to expanded vegetation growth.
The authors found that greater vegetation density at higher elevations in the Kings basin with the 4.1 degrees Celsius warming projected by climate models for 2100 could boost basin evapotranspiration by as much as 28 percent, with a corresponding 26 percent decrease in river flow.
Further, the relationships among evapotranspiration, temperature and vegetation density were similar across a broader area of the Sierra Nevada, suggesting that the impact of climate change on evapotranspiration and freshwater availability could be widespread.
“Most people have heard about the giant forests around Yosemite and Sequoia national parks, but these areas have not been a focus of this type of research. Understanding of Sierran hydrology has improved recently with the National Science Foundation’s Critical Zone Observatory, and data collected there allowed us to look at the problem from several perspectives,” Goulden said. “All of our analyses pointed in the same direction: An upslope expansion of forest with warming would cause a large increase in evaporative water loss and lead to reduced water availability.”
Bales is a professor of engineering and director of the Sierra Nevada Research Institute at UC Merced. The research was supported by the NSF, through the Southern Sierra Critical Zone Observatory (EAR-0725097) and a major research instrumentation grant (EAR-0619947), and by the U.S. Department of Energy’s Terrestrial Ecosystem Science program.
Peter asks if any of us dispute this article…. Hell no! More trees are another benefit of CO2, and I could list dozens. There are no concerns with increased levels since the next 10,000 ppm’s could not match the very first 100 ppm’s in warming effect.
More trees mean less uncontrolled runoff. The water still reaches the lakes, or sinks into the aquifers, and less floods out into the Pacific. The additional trees will hold the snow longer and release it slower.
There is no current downside to increased CO2, and only computer climate video games believe in the science fiction of dangerous warming.
Any natural increase in forest area is an enormous threat – to their “catastrophe” myth.
Those pesky trees! They’re always getting in the way of our solar panels and wind turbines, always trying to sneak back onto our bio-fuel farms too. You’d think they be too afraid to try after what was done to their parents. http://www.individual.utoronto.ca/william_s/images/homer_computer.gif
Any possibility that the increased evapotranspiration will result in greater rainfall further down wind? Seems to me I’ve read that increased forest cover often leads to increased rainfall. Maybe not here, but has the question been studied?
W^3
Well gee — there’s a solution to that “problem”. All that is needed is to load some airplanes with herbicides and spray away.
Ah, I see their problem; they plugged in a fantasized increase in temp of 4.1 degrees Celsius. When you start with a fantasy, it’s no wonder that’s where you end up. If my granny had wheels she’d be a wagon. If I had a granny, that is.
Shipping ice from the burgeoning Great Lakes to California Sierras. Or…desalination. Or …capture water from SUV exhaust. Or…move out of California. Whatever happened to ingenuity and industrialism?
If there is in fact more warmth, that means more vapor and clouds. More trees means more precipitation from capturing the vapor/clouds. It also means the snow and ice is more likely to melt intot heground and not sublimate. The assumptions of this study appears to be a zero sum game.But of course the clear intent is to raise yet more faux climate hysteria.
Peter, the American Southwest is in the DESERT! This is headshakingly stupid. Do you know where else is in the middle of a “mega-drought” – CHAD, EGYPT, LYBIA, ETHIOPIA, DJBOUTI, SAUDI ARABIA, ATACAIMA, NAZCA, and the rain-shadowed MOJAVE. These areas have been in multi-millenial droughts. It is because – wait for it – they are DESERTS! Just because California, Nevada, New Mexico, Arizona, Southern Utah, and Southern Colorado decided to urbanize in the middle of one does not make it any less of a desert. The San Fernado Valley is only useful because of three factors – irrigation, warm climate, and volcanic soils. BUT – it is still desert! Diverting irrigation to allow some silly chub or salamander to live is not a moral arguement that I wish to have.
If you are that worried about having enough fresh water to drink, move to Sierra Leone, Liberia, or Ghana: I hear they have plenty this time of year.
Now they are going to want to clear cut those areas to save the runoff rate? No! Here’s a perfect chance to move people out of the areas lacking water. Everybody to the cities! Let’s pack ’em in there.
Peter is all in. He’s worried. Every time he reads some climate article he get more convinced and alarmed.
He’s advocating the full Monty of climate action and is simply incapable of recognizing how mendacious the entire movement is.
We have 1000s and 1000s of Peters in Oregon.
Everyone of them thoroughly convinced earth and mankind are at grave risk.
The phenomenon is quite impressive in it’s cult like or parasitic nature.
There are simply too many millions of eco/green/sustainable/habitat invested activists who have hitched their causes to the AGW movement to make them ever let go.
California droughts come and they go. In the 1990s there was a 7 year drought. It ended and water increased. This current one will end too. Carlsbad is building after 12 years of Enviro Impact Studies, and various challenges in courts by enviros group, a major league desal facility. Will cost about a billion or so.Details can be found on the web. A dozen or so other similar projects litter the the cost North of there, but the Carlsbad is the first to actually break ground and employ people.
In the late 1800s some smart and industrious guys built a dam and a pipeline bringing Hetch Hechy water to SF Bay Area. Greening the Bay for generations to come. John Muir protested that action. Hence the heritage of the Sierra Club. Now 35 million claim California home, By Asian standards, this is rural. I expect this population to double in the next 50 years. Where will the water come from ?
I moved out and live in Nevada. I own a grape vineyard in the central valley. When we bought it the first thing I did was to expand the well water output. Our grapes are happy and will be harvested in about 4 weeks.
Michael Sphar,
You make sense. Your comment reminds me of the Auburn dam, back in the day. It was close to completion, after the state spent more than a billion dollars on it [at a time when $1 billion was a lot of money].
Then the enviro crowd got involved, and managed to shut it down completely. Now the water runs straight to the ocean.
Is there anything that these eco groups do that is good for the state, or the country? The net result of their meddling always seems to leave people worse off than before. But the snail darters are happy, I guess.
So that means the oceans will drop right?
If more of the water that comes to the land in the form of rain stays here, that means less is flowing back into the ocean. Plus, all the increased tree growth will capture more carbon.
So nature really is a self regulating system, who’d a thunk.
It gives a whole new wiev on the campaign to plant a tree in Africa!
More vita filler material here, try trans fat, wood paste, or pink slime next time.
I drive a couple of SUVs to compensate but they are still pretty effecfive (the enviros). Too bad about that Auburn dam. The California Water Resources system could use a few more dams. I’m not asking for 150 years of foresight like the Hetch Hetchy project, just another 50 years of scraping by so that the majority can shift towards a more conservative and pragmatic base (think more Chinese immigrants).
The authors found that greater vegetation density at higher elevations in the Kings basin with the 4.1 degrees Celsius warming projected by climate models for 2100 could boost basin evapotranspiration by as much as 28 percent, with a corresponding 26 percent decrease in river flow.
What models predict a 4.1C increase in temperature?
If there is an increase in the evapotranspiration of H2O, does that reduce the amount of temperature increase?
Will the increased rate of growth of plants reduce the increase of CO2 concentration?
Just in case you have not clicked the link here are the abstracts.
Such foolishness. A little controled harvesting and this isn’t just a non-problem but a side benefit.
I was watching ‘Location, Location, Location Australia’ last night. (my wife controls the remote.) They were looking at a shell of a house, all the internals removed because of the Brisbane floods. They pulled down a piece of mud left in the bones from the 1974 flood, that was about 3 foot higher than the latest one.
It has happened before. Brisbane is built on a flood plain.
Has anyone suggested increasing the amount of wood allowed to be harvested? Two birds with one stone.
I guess you can also ask about the effect of cutting them all down??
Increased avalanches in winter, increased topsoil loss during heavy rainstorms, more likelihood of flooding during the spring/early summer snowpack melt etc etc.
Swings and roundabouts, me thinks……
YAY!!!!
Count me in…I’d like some new furniture too.
“Defend your water rights from arboreal theft! Buy a chainsaw now! Special this week, 30% off!”