There is scientific consensus that global warming is under way, with serious impacts expected on agriculture, air and water quality, and biodiversity in California during the next century, the cover story of the May-June 2002 California Agriculture reports. The current issue of California Agriculture, including PDF-versions of research articles in full, can be viewed online at: http://danr.ucop.edu/calag/
In a peer-reviewed article, University of California meteorologist Bryan Weare reviews the most recent findings of the United Nations Intergovernmental Panel on Climate Change, an international consortium of hundreds of atmospheric scientists and experts.
“Few scientists dispute that human activity is causing the atmospheric concentrations of greenhouse gases and particles to increase, and that this, in turn, is leading to global climate change,� Weare writes.
Atmospheric concentrations of carbon dioxide, methane and nitrous oxide were stable until about 1900, after which industrialization and burning of fossil fuels caused them to increase substantially. Global mean temperatures are currently about 1*F higher than at any time in the past 1,000 years. Nonetheless, scientists continue to debate the extent of the resulting changes and how quickly they will occur. Current and expected impacts include: heavier precipitation events and more droughts, retreat of nonpolar glaciers, rising sea levels, decreases in snow cover, longer growing seasons, and earlier plant flowering, bird arrival and insect emergence.
Related news coverage in California Agriculture explores current climate-change events, such as the collapse of a 1,250-square-mile Antarctic ice shelf, and global political responses. Science briefs report on the effect of increased atmospheric carbon dioxide on nitrogen incorporation by plants, and the world’s most sensitive nitrogen dioxide detector, which has identified previously unknown contributors to global warming. An editorial explores how California will cope with climate change. Contact: Bryan Weare, (530) 752-3445 or bcweare@ucdavis.edu.
Also in the May-June 2002 issue:
Grower-winery contracts widespread in California: The use of agricultural contracts between farmers and processors has increased substantially in recent years. A survey by scientists affiliated with the UC Agricultural Issues Center found that 90% of wine grape growers use such contracts to secure buyers for their crops. Growers with more experience, larger vineyards, more expensive grapes and longer relationships with buyers were more likely to enter into contracts. Contact: Rachel Goodhue, (530) 754-7812 or goodhue@primal.ucdavis.edu.
Avocado thrips are a significant new pest: Since their arrival in 1996, non-native avocado thrips have become a major pest in California, with 80% of commercial avocado orchards sprayed to control them. In wide-ranging research, UC scientists determined their area of origin and compiled an inventory of potential pest thrips species in Mexico and Central America. A natural predator of avocado thrips, Franklinothrips orizabensis, is being reared and tested as a potential biological control agent. Contact: Mark Hoddle, (909) 787-4714 or mark.hoddle@ucr.edu.
New plum bark disease identified: After two Central Valley plum orchards mysteriously succumbed to plum bark necrosis–stem pitting disease, which destroys the trees, UC-affiliated scientists identified a new viruslike pathogen that is transmissible via grafts. Contact: Jerry Uyemoto, (530) 752-0309 or JKUyemoto@ucdavis.edu.
California Agriculture is the University of California’s peer-reviewed journal of research in agricultural, human and natural resources. For a free subscription, call (510) 987-0044 or write to calag@ucop.edu.