Drought in California and Climate Change: They are linked

A paper just out now in PNAS by Noah Diffenbaugh, Daniel Swain, and Danielle Touma shows that "Anthropogenic warming has increased drought risk in California." From the abstract:

... We find that although there has not been a substantial change in the probability of either negative or moderately negative precipitation anomalies in recent decades, the occurrence of drought years has been greater in the past two decades than in the preceding century. In addition, the probability that precipitation deficits co-occur with warm conditions and the probability that precipitation deficits produce drought have both increased. Climate model experiments with and without anthropogenic forcings reveal that human activities have increased the probability that dry precipitation years are also warm. Further, a large ensemble of climate model realizations reveals that additional global warming over the next few decades is very likely to create ∼100% probability that any annual-scale dry period is also extremely warm. We therefore conclude that anthropogenic warming is increasing the probability of co-occurring warm–dry conditions like those that have created the acute human and ecosystem impacts associated with the “exceptional” 2012–2014 drought in California.

Michael Mann and Peter Gleick have written a commentary for PNAS to accompany that research. The graphic at the top of the post is from that study. They note:

California is experiencing extreme drought. Measured both by precipitation and by run- off in the Sacramento and San Joaquin river basins, 10 of the past 14 y have been below normal, and the past 3 y have been the driest and hottest in the full instrumental record. A plot of temperature and precipitation anom- alies over the full instrumental record from 1895 through November 2014 shows that the 3-y period ending in 2014 was by far the hottest and driest on record (Fig. 1). As of the publication of this commentary, the state appears headed into a fourth consec- utive year of water shortfall, leading to massive groundwater overdraft, cutbacks to farmers, reductions in hydroelectricity gen- eration, and a range of voluntary and man- datory urban water restrictions.

A number of studies have examined the California drought to try to determine if it was "caused by" (or otherwise affected by) human greenhouse gas pollution. These studies vary in their level of attribution, but increasingly it is becoming clear that anthropogenic global warming has a very big hand in this.

Mann and Gleick tackle the problem of defining drought. There are multiple ways to do so, and they relate to different causes. The plethora of definitions and relevant variables allows for a given study to miss any global warming effect by picking certain factors and ignoring others. Studies that look mainly at inputs to the hydrological system (i.e., rainfall) tend to miss the output part of the equation, including evaporation, which is exacerbated by a warming climate. Mann and Gleick point out that the Diffenbaugh study adds significant weight to the idea that anthropogenic climate change has increased the frequency, magnitude, and duration of California's droughts. Perhaps more importantly, the Diffenbaugh study suggests "the emergence of a climatic regime in which all future dry years coincide with warmer conditions."

Gleick told me, "The scientific evidence showing the growing influence of climate changes on extreme events around the world, including the ongoing California drought, continues to pile up. The clearest piece of this is the record high, and increasing, temperatures, which directly influence the availability and demand for water, but there is also growing evidence that climate change is influencing pressure dynamics and atmospheric circulation patterns that either bring, or divert, water from the west coast of the United States."

So, the current drought in California is linked to human induced climate change, and in the future, this will be a more common phenomenon than it has in the base, according to the best available science. But what about other effects of climate change? I asked Michael Mann about the relationship between California Drought and his recent study showing that we should soon be entering a period (over the next couple of decades) during which heat that has been hiding in the oceans will be leaving it's watery milieu and joining us up here on the surface. He told me, "Here is the linkage I think is most relevant: the “faux pause”, in our recent study, was closely tied to the predominance of La Nina-like conditions in the tropical Pacific for a large part of the past decade, and these same conditions are closely linked with California drought (La Nina years tend to be drought years in California, while El Nino years tend to be wet years—though this doesn’t necessarily hold true for every single event). So one might imagine that a return to a greater tendency for El Nino-like conditions in the tropical Pacific over the next decade or two (which would spell an end to the “Faux Pause”) could actually be a mitigating effect as far as California drought is concerned. A bit counter-intuitive, but that’s best assessment here."

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One huge positive step California could take is to increase the free contraception program: Norplant II and condoms to anyone and everyone who wants them regardless of age, with no idea "parental consent" laws. Step two would be to limit the number of people entering the state from other states and other countries. Step three should be the end of constructing new housing. These three steps are necessary to meet the future droughts and future lack of snow pack in the Sierra Nevadas. It will eventually be required in the future, so it should be planned now.

The alternative is to fix the problem, but the corporate sponsors of USA's senators and legislatures refuse to even discuss the problem let alone the solution. The longer the USA government waits, the more Draconian the measures required to fix it. The Department of the Interior has already seized most riparian areas in the American Southwest from the families who used to own them; there will be a time when people will not be allowed to just pack up and move where they wish to. This is a "is," not an "ought:" it will happen--- the issue is how soon.

Thirty years from now people will be outraged at their parents for allowing the disaster to happen unchecked. Many young people today are already irate at what is being allowed to happen while Congress does nothing to fix the crisis.

By Desertphile (not verified) on 23 Mar 2015 #permalink

I think they should just start building vast greenhouses to replace the open air farming in the valleys .They won't need much water, then, and can also reduce other costs. They are already growing a disproportionate share of high value first world crops, this should be affordable.

Which does bring up a major point. If California's agricultural industry crashes, it will be really bad for the California economy but as far as I can tell it won't have as big of an impact on the food supply as if certain similar size area went belly up.

OK, so tonight we had Almonds on our beans. We would have to not have the almonds.

Here's a recent year's summary of exports in percentage of dollars of total exports.

Dairy and products210%
Table Grapes5%
Oranges and products35%
Tomatoes, processed4%
Beef and products2%
Seeds for sowing22%
Dried Plums1%
Peaches and nectarines1%
Raspberries and blackberries4,51%

Which does bring up a major point. If California’s reservoirs & groundwater supply crashes, it will be really bad for the California residents...

By Brainstorms (not verified) on 23 Mar 2015 #permalink

"... it will be really bad for the California residents…."

That is why the human population needs to decrease: to ease suffering.

Two weeks ago I once again suffered through the yearly survey of East Mojave Desert groundwater. The survey covers more than East Mojave: Amargosa Desert and parts of the Great Basin were also surveyed. I was assigned my usual eight springs and seeps to survey, and a dozen other volunteers surveyed over 100 others.

One of "my" springs (Goldstone) used to produce one gallon of water every 68 seconds, 23 years ago when I first participated in the survey. A cement berm was formed at the spring in the 1930s, with an iron pipe protruding from the berm. Every March In the past five years I sat there with a stop watch and counted drops per minute--- the average was 50 drops per 60 seconds. At the spring itself most of the brush and the six trees are now dead, and the ground is dry.

The spring at Squaw Tit is completely dry, and an owl now lives in the hole (both of us were startled when I pushed my face into the hole). When I first surveyed the spring I had to dig a trench and insert a six-inch diameter pipe in which water could flow to get an accurate measure of volume per minute.

Pachalka Spring: the water used to span about 22 meters from where the water emerged from the ground; it now spans 4 meters, and the trees that were planted by the Shoshone hermit who lived there in the 1850s are now dead. Fresh water used to fill a 55 gallon barrel there and two concrete cache systems, but it's all stagnant now.

Ivanpah Spring is now 100% dry. That happened before the Ivanpah Valley solar project started pumping water out of the ground, so they are not to blame.

Humans can desalinate water is they need to; it's the non-humans that will suffer the most.

By Desertphile (not verified) on 23 Mar 2015 #permalink

In reply to by Brainstorms (not verified)

A lot of people are saying "this is the new normal, adapt to it". But, I don't think this is likely the case. Whats likely is we are currently sampling the drought end of the (new climate) spectrum. Also certainly we will still have wet periods. I.E. the current water shortage, isn't likely to be forever, we will probably have years of plenty as well. Its just the the frequency of droughts -and especially severe ones is very likely to be a lot higher than historically.

BTW. So far temperature wise this year is far above last years record breaking pace.

By Omega Centauri (not verified) on 23 Mar 2015 #permalink

There's another important link between the drought and climate change. Hydro is an important source of California's electricity. Less water means less hydroelectricity, and a greater need for the fossil fuels that contribute to the lack of water. Desalination is a nice sounding solution, but it requires energy and resources. So does the production of renewables like wind, solar, and geothermal. And all solutions need time, money, and political will.

Moreover, the situation in California is just one example of how vulnerable the US has become. Not only has the US population increased, but much of the increase has occurred in water stressed states. By the time the Colorado River reaches the sea, it's been reduced to a trickle. Aquifers are being emptied, and in many quarters American exceptionalism has become the preferred term for pulling a bag over one's head and shutting out reality. In North Carolina and Florida head bags are now a political requirement.

By cosmicomics (not verified) on 24 Mar 2015 #permalink

@Desertphile: The elephant in the room here, to which Greg alludes @2, is agriculture. California agriculture is currently configured for a much wetter climate than they actually have, or are likely to have in the future. Currently, more than 80% of California's water goes to agricultural use, and much of that--probably more water equivalent than is used for residential purposes statewide--is exported. Any solution to California's problems must include adjustments to agriculture.

That means the rest of us will have to adjust, too. Almonds will become a luxury, since there aren't many other places in the US with a suitable climate, and it takes several years for an investment in an almond grove to pay off. Fresh winter vegetables will have to be greenhouse-grown--but then you don't have to grow them in California, but save on transport costs by growing them closer to your markets. Beef and dairy operations are probably better off in places like Wisconsin or Vermont, which aren't so constrained by water availability. Florida and South Texas can take up some slack on citrus fruits, although they have water issues of their own.

To some extent, market forces are already cutting into the desirability of moving to California. Bay Area real estate prices, especially the more desirable towns, are flat out ridiculous--of other US markets, only Manhattan comes close. (I know people who have bailed out of California for exactly that reason.) LA and San Diego aren't as bad, but still quite pricey compared to most US markets. And a lot of people will leave the Central Valley as its economic base, agriculture, literally dries up. California did not gain any additional US House seats from the 2010 census compared to what it had after the 2000 census--IINM that was the first time since becoming a state that California's Congressional allotment did not increase in size following a census.

By Eric :Lund (not verified) on 24 Mar 2015 #permalink

I am not sure transport costs will outweigh benefits of growing in a very sunny environment when it comes to greenhouses, but it is a factor.

#7 Eric Lund:

"market forces are already cutting in to the desirability of moving to California"

"real estate prices, especially the more desirable towns, are flat out ridiculous"

You do see the contradiction there, right? In terms of the most fundamental principle of markets?

As several people have commented, ag uses four times are much water as all the people in the state. We don't have an overpopulation problem as much as a water seniority rights problem.

We don’t have an overpopulation problem as much as a water seniority rights problem.

Attempts to solve that political problem have mostly failed. One failure was the series of sabotage, years ago, of new gold courses in the deserts (destroying water pumps mostly) after legal attempts failed.

Some people still have no idea there was even a Water War between California and Arizona, where armed soldiers from both states' National Guards were sent out to oppose each other to use violence to resolve the conflict. There is a brief, and badly written, Wikipedia article on the subject that perhaps this coming winter I'll improve.

By Desertphile (not verified) on 26 Mar 2015 #permalink

In reply to by Phil (not verified)


Ag is only about 3% of the CA economy.

Even in a worst-case megadrought, ag will be far from wiped out.

Even in a worst-case megadrought, there will be plenty of water for urban uses (currently about 20% as noted) and still some left over for irrigation.

Historical megadroughts still saw wet years.

As we are seeing now, the idling of ag capacity in a megadrought will be progressive, not abrupt, based somewhat on reduced surface supplies but increasingly on groundwater that becomes too expensive to pump or too salty/contaminated to use.

If this is a megadrought, expect groundwater basin damage (subsidence and contamination) to get much worse before it's reined in. Such damage is essentially permanent.

By Steve Bloom (not verified) on 26 Mar 2015 #permalink

A climate change related article is refreshing to see, however is this evidence enough to assume the droughts are as a result of climate change? And not just the regular cycle of water surplus and lack of water that every area goes through?

By Dean Carlisle (not verified) on 29 Mar 2015 #permalink

No, droughts are not the result of climate change. No one said they are.

By Desertphile (not verified) on 29 Mar 2015 #permalink

In reply to by Dean Carlisle (not verified)

Climate change will always be a major cause of droughts.Solutions to combat droughts have to be implemented.I can't say that they should harvest rainwater and recycle water as there is less precipitation.


By Maria Moreroa (not verified) on 02 Apr 2015 #permalink

The Washington Post and The New York Times have had good and extensive coverage of the drought. Some of the articles use the drought to question American assumptions of endless resources and endless growth.

As West struggles with drought, complicated water politics loom

California is hotter than ever, she said. She feels it every day.
“When I moved here nearly 10 years ago, we actually had a change of seasons through the winter,” she said. “It was lovely. Now it feels like summer all the time, and it never rains. It has just gotten hotter over time.”


California Drought Is Worsened by Global Warming, Scientists Say

Endless Growth
A punishing drought is forcing a reconsideration of whether the aspiration of untrammeled growth that has for so long been the state’s engine has run against the limits of nature.

California snowpack fades to shocking record low as water restrictions ordered

In most cases reality is stronger than ideology. In Denmark people are more concerned about the environment than they were a few years ago. It looks like the same thing is happening in the U.S.

By cosmicomics (not verified) on 05 Apr 2015 #permalink

Governor Brown has announced ways people can stop wasting water in the state.The drought really has to end .Farms,homes and business are badly affected.

By Thembi Moloko (not verified) on 06 Apr 2015 #permalink

Climate change opens our eyes to conserve our environment.This is a lesson to humankind to stop wasting water.I saw pictures of one of California's lake.The change is evident.

By Prudence Masufi (not verified) on 06 Apr 2015 #permalink

Population growth and climate change, particularly high pressure temperatures causes droughts. I have learned that severe droughts affected most of California from 1987 until early 1993, where groundwater and surface reservoirs rapidly decreased to their lowest levels in 15 years. There are methods in which California can implement to save water; firstly develop irrigation processes to save water, building dams, drilling wells, building artificial reservoirs, harvesting rain water when they good rainfall etc. Question is, how is drought linked to human induced climate change? In that aspect, I would be honored if I can get clarity.

By P.M Bestenbier (not verified) on 07 Apr 2015 #permalink

Population growth and climate change, particularly high pressure temperatures causes droughts. I have learned that severe droughts affected most of California from 1987 until early 1993, where groundwater and surface reservoirs rapidly decreased to their lowest levels in 15 years. There are methods in which California can implement to save water; firstly develop irrigation processes to save water, building dams, drilling wells, building artificial reservoirs, harvesting rain water when they good rainfall etc. Question is, how is drought linked to human induced climate change? In that aspect, I would be honored if I can get clarity. u14248043

By P.M Bestenbier (not verified) on 07 Apr 2015 #permalink

I did a back of the envelope calculation (in my head). If LA were to cut its water use 25 percent it is the same as ag cutting its use 2.5 percent. I have to say this does not sound like an overpopulation problem to me. It sounds like a water misuse problem by agriculture. Though of course your point is taken is that having a large population in the desert is counter intuitive.