A car sits in dried and cracked earth of what was the bottom of the Almaden Reservoir on January 28, 2014 in San Jose, California. (Justin Sullivan/Getty Images)
A car sits in dried and cracked earth of what was the bottom of the Almaden Reservoir south of San Jose on Jan. 28. (Justin Sullivan/Getty Images)

California’s current drought is pretty exceptional — like the driest in about a millennium — according to an article published today in the journal Geophysical Research Letters by scientists with the University of Minnesota and Woods Hole Oceanographic Institution in Massachusetts.

But how could they know that? There weren’t a lot of rain gauges in California in 800 A.D. — at least, not the plastic kind.

So authors Daniel Griffin and Kevin Anchukaitis looked to tree-ring samples from California blue oaks.

Pencil-like tree-ring cores are collected non-destructively using a Swedish increment borer in May, 2014. (Daniel Griffin/University of Minnesota)
Pencil-like tree-ring cores are collected non-destructively using a Swedish increment borer in May, 2014. (Daniel Griffin/University of Minnesota)

“California’s old blue oaks are as close to nature’s rain gauges as we get,” said Griffin, a NOAA Climate and Global Change Fellow with Woods Hole Oceanographic Institution. “They thrive in some of California’s driest environments.”

The researchers collected their own blue oak tree-ring samples from south and central California, giving them a pretty good idea of yearly precipitation in the area back to 1293. They then augmented their samples with data from the North American Drought Atlas and the National Oceanic and Atmospheric Administration Palmer Drought Severity Index.

The result: The study estimates that in the past 1,200 years, there have been 66 dry periods lasting three-to-nine years and 37 more-severe, three-year droughts. But not one of them has been as extreme as the one beginning in 2012, despite some years in the past seeing similarly low precipitation.

It’s not only lack of rain that makes a drought, though. Record-high temperatures added to California’s strife to make this dry spell the worst in more than 1,000 years, according to the study. The researchers estimate high temperatures have intensified the drought by about 36 percent.

UC Berkeley geology professor and researcher Lynn Ingram said the study’s findings appear solid.

“The tree-ring records provide the highest resolution as they have annual growth layers,” she said, adding the study provides a “cautionary lesson” about how human-caused warming “may already be impacting climate and water in California.”

Watch the California drought progress from the beginning of 2011 to the end of 2014 below. The NOAA U.S. Drought Monitor released the latest outlook today, up-to-date as of Dec. 2. More than half the state is now in “exceptional drought,” defined as “exceptional and widespread crop/pasture losses; shortages of water in reservoirs, streams, and wells creating water emergencies.”


Click on the legend for a description of each drought category.
Click on the legend for a description of each drought category.

This animation shows California’s drought through its development, from January, 2011 through early December 2014, as expressed by NOAA’s U.S. Drought Monitor. (Olivia Hubert-Allen/KQED)

Study: California Drought Most Severe Dry Spell in at least 1,200 Years 5 December,2014Alex Emslie

  • azaredaniel

    California we are in trouble, aside from the crisis drought, we should also keep in mind Fracking, how much water have we used to Frack ? and the companies that use California Water to fill their plastic bottles, how much water, our they taking, each year ?

    California currently has a Feed in Tariff that does not allow home owners to participate in the State mandated goal of 33% renewable energy by 2020.

    California also does not allow the homeowner to oversize their R.E systems, as of now, your local utility has allowed only 80% homeowner generation from your R.E system.

    California has 2 different Energy policies Net-metering and a Feed in Tariff.

    Net metering the energy policy for homeowners, allow you to bank excess electricity from R.E systems for future credits. The credits you accumulate

    are at the retail rate, and are reviewed at the end of the year. It will be written off with a thank you from the utility and no payment to the homeowner for producing more than what you use.

    Net metering has allowed third party leasing companies to replace one utility with another.

    A California Residential Feed in Tariff would allow homeowners to sell their R.E. to the utility, protecting our communities from Poison Water, Grid Failures, Natural Disasters, Toxic Natural Gas and Oil Fracking. It would also create a new revenue stream for the Hard Working Taxpaying, Voting, Homeowner.

    “Examples of Net-metering slow down Renewable Energies:1. Renewable Portfolio Standards (RPSs) which create de facto caps on the deployment of renewable energies (the Germans do not have any RPSs, their Feed in Tariff has no caps.

    2. Net-metering caps, most states only allow a small percentage of one to two percent of peak load to be net metered.

    3. Third party leasing companies like Solar City, Sun Run, Verango and others fight tooth and nail to protect scarce capacity carve outs (from the States RPSs) so as to bolster their chosen business model.” Bob Tregilus

    No one is fighting for the Hard Working, Taxpaying, Voting, Homeowner, we can change that with a Ca. Residential Feed in Tariff Energy policy that allows everyone to participate. Homeowner’s, Small and Large Businesses, Small and Large farmers, and Industries, have the right to sell Renewable Energy electricity back to the utility.

    We need sustainable and successful energy solutions now and a Residential and Commercial Feed in Tariff is sustainable and will help ensure our survival.

    Vote Solar Initiative is a Sierra Club and Solar Leasing Companies platform to ensure that One Utility will take the place of Another through the continued use of Net Metering.

    We need a Policy that will enable Hard Working, Voting, Tax Paying Citizens, get a chance to participate in the States goal of 33% Renewable Energy by 2020 through a California Residential Feed in Tariff.

    California, there is enough Residential Solar to power 2.25 San Onofres, couple that with a Commercial Feed in Tariff and we can solve some of these environmental and electrical generating problems.

    This petition will ask the California Regulators and Law makers to allocate Renewable Portfolio Standards to Ca. Home Owners for a Residential Feed in Tariff, the RPS is the allocation method that is used to set aside a certain percentage of electrical generation for Renewable Energy in the the State.

    Sign And Share this petition for a California Residential Feed in Tariff.
    http://signon.org/sign/let-california-home-owners

  • GetHubNub

    How can this be when these areas are really deserts and the only reason we live in this area is due to technological breakthroughs in water distribution from other areas? How can a desert have any kind of drought?

Author

Alex Emslie

Alex Emslie is a criminal justice reporter at KQED. He covers policing policy, crime and the courts.

He left Colorado and a career as a carpenter in 2008 to study journalism at City College of San Francisco. He then graduated from San Francisco State University's journalism program with a minor in criminal justice studies. Prior to joining KQED in 2013, Alex freelanced for various news outlets including the Huffington Post, San Francisco Chronicle, San Francisco Examiner and Bay Guardian.

Alex is proud of his work at KQED on a spike in fatal officer-involved shootings in Vallejo, which uncovered that a single officer shot and killed three suspects over the course of five months. Alex's work with a team at KQED on police encounters with people in psychiatric crisis was cited in amicus briefs before the U.S. Supreme Court. He received the Northern California Society of Professional Journalists Best Scoop award in 2015 for exposing a series of bigoted text messages swapped by San Francisco police officers. He was honored with 2010 San Francisco Peninsula Press Club and California Newspaper Publishers Association awards for breaking news reporting on the trial following the shooting of Oscar Grant. Email: aemslie@kqed.org. Twitter: @SFNewsReporter.

Sponsored by

Become a KQED sponsor