Climate change could decimate California’s major crops, and that should concern everyone

A new study has dire warnings for California -- and the entire U.S. food system.

Workers sort and package freshly harvested cantaloupes on a farm on August 22, 2014 in Firebaugh, California. (CREDIT: Justin Sullivan/Getty Images)
Workers sort and package freshly harvested cantaloupes on a farm on August 22, 2014 in Firebaugh, California. (CREDIT: Justin Sullivan/Getty Images)

A new study, published on Tuesday in the journal Agronomy, contains a dire warning for anyone in the United States who eats: By the end of the century, climate change could wreak havoc on California’s major crops, prompting a sharp downturn in the state’s ability to produce things like almonds, wheat, and corn.

“The detailed literature study on climate change in California clearly reveals that temperatures are increasing at significant rates,” the study concludes, adding that precipitation has become increasingly variable and snow pack increasingly vulnerable as temperatures warm.

“Given that California is a world leader in the production of many important specialty crops, without timely and effective actions, negative climate change impacts may further intensify the challenges to meet local and global food demands.”

The study, led by researchers from University of California Merced and Davis, looked at both past trends and potential future impacts of climate change on temperature, snowpack, and extreme events like drought, heatwaves, and flooding. Researchers then looked at how those projected changes would impact some of California’s most important crops, including fruits and nuts.

The study found that staple crops like wheat and corn were moderately affected by future increases in climate change, while fruit crops were severely impacted by climate change — under a high emissions scenario, a 4 degree Celsius (7.2 degree Fahrenheit) rise in temperatures could reduce fruit yields by 40 percent in some regions of the state.

Perhaps more urgently, the study found that the Central Valley will not be suitable by mid-century for species like apples, cherries, and pears under any emissions scenario.

California is an agricultural powerhouse, growing over a third of the country’s vegetables and two-thirds of the nation’s fruits and nuts. It produces 80 percent of the world’s almonds and is the world’s largest supplier of canned tomatoes.

But agriculture depends on a predictable climate and a stable supply of water — especially in California’s fertile but arid Central Valley, where farms are irrigated with water brought down from the Sierra Nevada mountain range through a network of dams and canals. In the entire United States, California ranks only behind Nebraska in terms of irrigated land, with some 9 million acres of farmland irrigated each year.

Snowpack has proven to be especially vulnerable to changes in temperature, particularly in the West. This year, high temperatures and below-average precipitation have combined to a devastating effect in the Sierra Nevada mountains, which saw snowpack levels just 14 percent of normal at the beginning of February (though a large snowstorm expected to hit in the coming days could change that).

The combination of a state deeply entrenched in farming and deeply dependent on irrigation to keep those farms viable makes California especially vulnerable to climate change. Add other climate-related consequences into the mix — like increased pest activity or an increased frequency of heat waves — and California could face serious vulnerabilities in its food production by the end of the century.

It’s possible that some of the crops that California grows — the vegetables and fruits — could be grown elsewhere in the country as California’s ability to produce these crops lessens.

But much of the country’s agricultural acreage outside of California is already rooted in producing commodity crops, like corn and soybeans. These are crops that require farmers to invest in expensive farming equipment upfront and, because of farm subsidies, tend to be more lucrative for farmers than specialty crops like fruits and vegetables.

To protect against future vulnerabilities in California’s agricultural sector due to climate change, the study’s authors urge policymakers to begin taking steps now to understand how individual crops will be affected. They also urge policymakers to look into solutions like breeding more heat-resistant crops, or drought-resistant crops, to better guard against potentially declining yields.

As the report concludes: “California agriculture is very diverse and since each crop responds to climate differently, climate adaptation research should be locally focused along with effective stakeholder engagement and systematic outreach efforts for more effective adoption and implementation.”