& Other Perennial Crops
By Erica Lundquist, Ph.D.
Former LCWC Viticulturist
The objectives of the conference were to “Stimulate dialogue among academics, industry leaders and policy experts regarding climate change implications that could affect the sustainability of the California wine industry and other perennial crops.” Representatives from media were not invited in order to give a chance for open discussion.
Presentations ranged from global perspectives to potential issues for California winegrowers and wineries. In this summary of the conference I will start with a brief description of global warming/ global climate change and then cover presentations moving from a global to local level. A great deal of policy and science was covered, and I am certainly not an expert on most of it, so I cannot vouch for the accuracy of this entire summary.
For those of you who missed Al Gore’s movie (or some other presentation), global warming occurs because certain gases emitted both naturally and through human activities allow sunlight (short wave radiation) through our atmosphere to the earth’s surface, but reduce the emission of heat (long wave radiation) back out to space. Carbon dioxide, released from burning fossil fuels such as coal and petroleum, is the major greenhouse gas produced by human activities, however other gases such as methane and nitrous oxides are important contributors.
On average the earth’s temperature is climbing, but most scientists prefer to call the process global climate change rather than global warming. This is because the increase in temperature is not uniform across the globe, and some areas are actually cooler. Also climates are changing, dry zones encircling the globe (south of California) are expanding northward, while precipitation is increasing north of California. Also extremes in weather (both high and low temperatures, drought and floods) appear to be more common.
At this conference the reality of increased global temperatures and the human contribution to this increase were not in dispute. Chris Field, Director of the Department of Global Ecology at the Carnegie Institution, pointed out that at the U.N. all 120 countries were in agreement on this issue when they published the U.N. Intergovernmental Panel on Climate Change Assessment 2007 Report.
He suggested that IPCC models for future climate change were fairly conservative, as all 120 countries had to reach a consensus. The models all agree that temperatures will continue to rise given the current state of our atmosphere, but depending on the actions that are taken, the temperature rise could be from 1-5oC (2-9 oF) by 2100. With the lower temperature rise there would probably be relatively few consequences of global climate change and the opportunity to adapt. At the high end of the range, consequences would be drastic.
Some of California’s greatest challenges, according to Chris Field, will be water availability and wildfires. The snow pack in California is very sensitive to temperature increase (much of it is preserved at just below freezing temperatures.) Because it is a major source of water storage for much of the state, the entire state will be impacted by decreasing snow pack. Another big challenge in California will be increased wildfires with increasing temperature.
Giving a global and agriculture-level perspective on solutions to climate change, Susan Capalbo, an economist/professor at the Consortium for Agricultural Soil Mitigation of Greenhouse Gases at Montana State University, first reminded the group that fossil fuels are abundant enough to remain the lowest-cost energy option for the foreseeable future. She described how agriculture has a role to play in short-term, 10-20 year, sequestration of carbon while terrestrial carbon sequestration is being developed as a long-term solution. Carbon sequestration means converting carbon (present as carbon dioxoide) from the atmosphere into soil organic matter or more permanently in some kind of solid form (terrestrial sequestration). Agricultural carbon sequestration can occur by adding more organic matter to soil as cover crops or compost, or by reducing or eliminating tillage. Scientists are trying to find ways to scrub carbon dioxide from power plant emissions and lock it up in solid form, however this cannot yet be done at a reasonable cost.
Governor Schwarzenegger signed into law AB 32, the California Global Warming Solutions Act of 2006. This mandates that California greenhouse gas emissions (GHG) will reduce to 1990 levels by 2020, and 80% below 1990 levels by 2050. That sounds like a challenge, but according to the scientists at the conference, that is what is required. For California’s efforts to be successful, the rest of the globe needs to follow suit. It is interesting to note, however, that by itself California is the 12th greatest emitter of GHG.
Chuck Shulock, Director of Climate Programs for the California Air Resources Board talked about how they are hiring 123 new positions for the climate program, how they have formed committees to insure that local air pollution is not exacerbated, to get input from business on technology advancement and economic impacts, and to develop market-based “cap and trade” approaches to GHG reductions. A Climate Action Team coordinates all the state agencies that are involved.
There is a Western Regional Climate Action Initiative which includes California, Washington, Oregon, Arizona, New Mexico, and recently Utah, Manitoba and British Columbia. This group is setting common regional goals, and it will be especially helpful in managing electricity efficiently. Thirty states have joined the Climate Registry. These states are developing common protocols for measuring and tracking GHG emissions and for setting up regulatory and market-based approaches to GHG reductions.
A dilemma with government’s ability to tackle the problem is that action should be started immediately, however it takes time for government to develop regulations and a cap and trade program. It becomes a disincentive for business to make voluntary reductions when they don’t know if these reductions will recognized under new regulations.
At the farm/winery level, Patsy Dugger, Senior Program Manager Supervisor for the Agriculture and Food Processing Program at PG& E, talked about programs and incentives PG&E has for energy conservation. PG&E has found that energy conservation is more cost effective for them than building electricity generating capacity. She pointed out that wineries are the largest food processor sub-segment, and vineyards are the largest agriculture sub-segment, with 16 and 18% of electric use, respectively for their sub-segments. PG&E has numerous rebates, and customized incentives depending on the project. They provide consultants for design assistance to achieve maximum energy assistance, and they carry out energy audits and pump tests to show where businesses can conserve energy use.
Bryan Jenkins, UC Davis Professor and Director of the California Biomass Collaborative, discussed research on the potential for biomass fuels and cogeneration. Unlike the use of fossil fuels (coal, oil) where carbon goes one way from a geologic form to the atmosphere, the carbon from the burning of biomass fuels (plants) is cycled back into the plants when they grow again. Even so researchers are documenting “life cycle” emissions from the use of biofuels, and some actually have a net contribution to GHG emissions. For example, ethanol produced from corn has minimal GHG reduction benefits, and when the plant for ethanol fermentation is coal-fired, there is a net contribution to GHG. If researchers can find a way to use cellulose (the main structural material in plants), the amount of ethanol produced from plant matter could be greatly increased.
Roger Boulton, UC Davis Viticulture and Enology Professor, pointed out that conditions (low temperature, high CO2 concentrations) during wine fermentation are very conducive to the capture of carbon dioxide produced during fermentation.
An interesting discussion at the farm level came from UC Davis Professor, Ted Dejong. In discussing tree crops, he pointed out that climate/weather variability is one of the biggest challenges. For example, he pointed to a complete failure of the 2004 prune crop due to temperatures in the 80s during bloom, and he discussed how drought stress during the summer and fall (especially problematic if irrigation cutbacks are ordered) causes defects in next year’s cherries and peaches, because buds are differentiating during this time period. I can think of potential analogous problems for winegrapes such as high temperatures during fruit ripening leading to yield and quality loss, rainy and cool spring conditions prolonging and interfering with bloom, etc.
David Block and Mark Matthews form the UC Davis Department of Viticulture and Enology tackled whether increased temperature reduces fruit quality, but had no useful answers. David Block came up with a very rough predictive model of the affect of increasing temperatures on Cabernet Sauvignon fruit quality, and Mark Matthews pointed out that there is very little conclusive research on the subject. (My own take on this topic is that specific weather events as discussed in the previous paragraph are likely to confuse attempts to study the topic. Even if researchers can set up experiments in controlled chambers, they will have a tough time growing enough fruit to make wine, and there would be large numbers of potential temperature scenarios to investigate. In the field year to year weather events present a complication.)
As government decides how to implement a GHG reduction program, there is a possibility that growers could be paid for sequestering carbon. Johan Six, from the UC Davis Plant Science Department and Dave Smart from the Viticulture & Enology Department, discussed what is known about carbon sequestration in California agricultural systems (not a lot). Johan Six studies annual cropping systems (wheat, corn, tomatoes). He found that organic matter additions such as the use of cover crops or adding compost, can increase carbon sequestration. He found that reduced tillage did not help increase carbon sequestration. In contrast to Midwest studies where no-till systems help to increase soil organic matter, the cropping systems he looked at in California are reduced tillage systems, (have some tillage), and did not sequester more carbon than conventional tillage.
Agriculture produces other major greenhouse gases. Methane production is largely a problem for livestock industries. Nitrous oxides are emitted from cropping systems. They have the ability to trap more heat than carbon dioxide, so even though they are emitted at much lower levels, their effect is substantial. Nitrous oxides come from microbial conversion of nitrate. Three factors contribute to higher nitrous oxide emissions, low oxygen, high nitrate, and high organic matter availability. Low oxygen occurs due to wet conditions, and all forms of nitrogen are readily converted to nitrate under warm summer conditions. Nitrous oxide tends to be released in pulses (e.g. just after irrigation, or just after tillage) and more research needs to be done on how to avoid conditions that produce it.
Dave Smart discussed the limited amount of research he has done in vineyards. He has found an indication that reduced or no tillage increases carbon sequestration. He pointed out that although vineyards are low users of nitrogen fertilizer, it is generally applied in a concentrated area in the drip zone, producing at least two of the three favorable conditions for nitrous oxide emissions. These researchers, and others at the conference agreed that there needs to be more research to understand the potential for GHG reductions from agriculture. Eventually this could mean money in growers pockets as AB 32 goes into action.
Getting on a soap box, my personal view is that reducing potential climate change is tremendously important. People, however, do not respond to intangible threats in the (apparently) distant future. Many people also focus on a few areas where knowledge is incomplete, or where mistakes have been made, and fail to acknowledge the substantial evidence and overwhelming scientific and international consensus on the issue. I am confident that we have the knowledge-base and technical and financial resources to solve the problem. The new industry for GHG reductions will be profitable to many (including, perhaps farmers). The main challenge, therefore, is summoning the political will to deal with climate change.