America's 2019 harvest is already in trouble

As farmers plant their 2019 crops, hopeful for an abundant harvest, they are unknowingly battling history. Past wildfires and other tree loss in California will likely interfere with U.S. food crops, based on emerging results of our own and colleagues’ research. An estimated 147 million trees in California forests died between 2010 and 2018, an unprecedented loss. Deforestation could cause millions of dollars in lost agricultural production throughout the U.S. But policy and practice still fail to recognize the interdependence of our wild and cultivated lands.

We humans tend to think of ourselves as affected by proximate things that we can see, hear or touch.  But scientists have for some time been aware of “teleconnections” that trace our interdependence with distant places. Most people now understand that El Niño impacts weather in the U.S. This is a teleconnection — ocean temperatures in the Pacific affect weather around the globe, and these changes influence agricultural production in the U.S., Africa and southeast Asia.  


Ecosystems, such as forests, also drive teleconnections. At the regional scale, vegetation affects how energy and water is exchanged with the atmosphere. This influences atmospheric circulation globally. When there is a large enough change in an ecosystem, our models show that temperature and precipitation patterns are altered in distant locations. We call these relationships “ecoclimate teleconnections.” We have the capacity to map where those changes can occur. Our work uses computer simulations to show how tree loss in specific parts of the United States can cause agricultural losses elsewhere.

Forest losses in the Pacific Southwest, which encompasses most of California, could have a serious impact on American food production in the Midwest and South, we found when we examined ecoclimate teleconnections across the U.S. National Ecological Observatory Network (NEON). We estimate that the cost of California forest loss to U.S. agriculture could total more than $4.5 billion.

Although these estimates assume an extreme scenario — total loss of California’s forests — they are too stark to ignore. Data from across the U.S. and the world indicate that large-scale tree die-off is likely to continue as the world warms and droughts intensify. Forest loss is a predictable feature of climate change.  

We cannot change the past; but we can change the future. The U.S. Forest Service (USFS) is part of the U.S. Department of Agriculture (USDA). This structure should facilitate strategic management that recognizes good stewardship of our forests safeguards agricultural production. Unfortunately, there is little evidence of coordination between the federal government’s roles in agriculture and forest management.

Since 1995, the percentage of the USFS budget dedicated to firefighting grew from 16 percent to more than half — at the expense of forest management. In 2018, Congress authorized funding to pay for firefighting without borrowing from other parts of the USFS budget. This fix could free up as much as $1 billion dollars — every year — for other activities beginning in 2020.

The USFS must use this flexibility to rebuild forest management capacity. More resources are needed for thinning, prescribed fire and other treatments that address the climate change-driven challenges causing forest die-off and feeding fires. More staff must be added to complete critical environmental reviews that will arm the agency with scientific data to make informed forest management decisions.

Scientists frequently struggle to communicate our work to the public in a way that informs choices about our natural resources. But this one is easy: It is better to prevent fire than to try to extinguish it.  Encouraging more holistic approaches at the USDA and adjusting USFS resources to prioritize prevention are essential steps toward safeguarding U.S. agriculture through forest protection, though neither is a panacea. The causes of the epidemic of wildfires are complex and certainly involve climate change. Though many of these forests are adapted to fire, drought and insects have weakened the trees’ defenses. It’s important to note, however, that the area of tree loss due to logging in the Western U.S. exceeds that of drought and insect-driven tree die-off — for now.

Preventing additional catastrophic fires and the threats they pose to agriculture will require new investments and new approaches in a warmer world, especially reducing emissions as fast as possible.

This is urgent work. The destruction of forests limits our ability to grow food. The fact that these fires happen in California rather than Iowa does not change the disturbing fact that we are burning up our nation’s food supply.

Laura López-Hoffman is an associate professor in the School of Natural Resources and the Environment & Udall Center for Studies in Public Policy at the University of Arizona.

Aaron Lien
is an assistant research scientist in the School of Natural Resources and the Environment at the University of Arizona

Abigail Swann
is an associate professor in the Department of Atmospheric Sciences & Department of Biology at the University of Washington.