Earth’s temperature has risen 1° F in the last 100 years — a small number with a profound impact for California. According to scenarios developed by the Intergovernmental Panel on Climate Change (IPCC), our planet will heat up another 1° F to 2.3° F by 2034 — an accelerating change that will take place over the course of just 25 years, rather than 100. In its 2007 reports, the IPCC concluded that climate change was "unequivocal."

The entire April-June 2009 issue of University of California’s California Agriculture journal is devoted to news and research on climate change and how it will fundamentally alter California’s environment and landscape, agriculture and food quality. The issue is available online: http://californiaagriculture.ucop.edu/0902AMJ/toc.html.

“California’s warmer winters and springs have led to reduced snowpack, increasing the seasonality of water flows and directly affecting our ability to grow plants, produce food and support growing populations,” Barbara Allen-Diaz, UC assistant vice president for agriculture and natural resources (ANR), writes in April-June 2009 issue of California Agriculture. “Wildfires are increasing; crop pests are expanding their ranges. ‘Natural disasters’ — such as droughts, Santa Ana winds, tornados, higher intensity rainfall events and fire — are more frequent and severe.”

California’s $37 billion agricultural industry will be severely affected by the coming changes. “Recent and predicted increases in temperature will have major impacts on where plants can be grown. Changing temperatures will also likely shift the range of native plants, and even cause some to disappear altogether,” writes Allen-Diaz, who shared the 2007 Nobel Peace Prize with about 2,000 IPCC scientists and former Vice President Al Gore.

The April-June 2009 issue of California Agriculture journal includes the following peer-reviewed research findings:

•    UC Davis meteorologist Bryan Weare, faculty chair of the special issue, reviews the science behind the IPCC’s comprehensive 2007 reports and summarizes the predicted changes to California’s climate, weather, growing conditions, pollution, sea level and other factors.

•    New research by UC Davis plant scientist Arnold Bloom suggests a mechanism to explain why initial increases in crop production due to “CO2 fertilization” decline rapidly, a finding with important implications for hunger and nutrition worldwide.

•    A review by UC Riverside entomologist John Trumble and graduate student Casey Butler predicts that the numbers and kinds of invasive insect pests will increase because of rising temperatures. Pest insects will consume more of certain plants due to their higher carbon and lower nitrogen content, and the reduction in winter chill periods will allow pests to breed throughout the year.

•    A controlled chamber study by UC Davis associate professor Frank Mitloehner and colleagues measures the actual emissions of greenhouse gases by dairy cows.

•    Computer modeling by UC Davis economists and colleagues demonstrates how alternative agricultural practices such as cover cropping can have a significant impact on the amounts of greenhouse gases emitted from fields.

•    UC Davis economist Richard Howitt and colleagues conduct a survey of Yolo County growers and develop an economic model to identify sustainable fertilization practices, proposing incentives for farmers to incorporate carbon sequestration into everyday practice.

•    In a review of carbon trading, UC Davis economists Deb Niemeier and Dana Rowan discuss how global carbon markets are evolving as tools to reduce greenhouse-gas emissions.

California Agriculture is the University of California’s peer-reviewed journal of research in agricultural, human and natural resources. For a free subscription, go to: http://californiaagriculture.ucop.edu, write to calag@ucop.edu or call (510) 642-2431 x33.

Note to editors:  To request a hard copy of the journal, e-mail janet.byron@ucop.edu.