WHAT CAN WE DO? There are two basic types of response to climate change: working to adapt to or manage the impacts experienced, and trying to prevent or minimize further change (mitigation). These are not mutually exclusive, and in fact, both are increasingly regarded as necessary.

Grapegrowers are highly resourceful, and some adaptation-options to warmer temperatures are likely to be pursued. These might include new trellising techniques, wider adoption of precision irrigation practices, and planting of new grape varieties in existing sites (including breeding new, more heat-tolerant varieties). However, this is where the celebrated geographical specificity of wine may limit adaptation-options. How would consumers and producers feel about Russian River Cabernet Sauvignon instead of Pinot Noir, or about some heat-tolerant but unfamiliar Spanish varieties replacing Cabernet Sauvignon in Napa Valley?

Genetic solutions seem unlikely. Despite great advances in grape breeding, which have resulted in the adoption of many new varieties in the table grape and roostock industries, essentially no new varieties of wine grapes have been widely commercially adopted in the last 50 years. Another option is to shift the location of plantings, for example, to cooler regions closer to the coast or further north. But this presents obvious problems for small growers with limited holdings - and long traditions - in a specific region.

In order to avoid warming that would entail unacceptably high levels of negative impacts, the European Union has determined a goal of limiting the warming experienced to less than 2°C (3.6°F) above pre-industrial times. This would probably require stabilization of CO in the atmosphere at or below 450 ppm, which would, in turn, require that global emissions peak within the next several years to two decades at most, and then begin to decline.

California has recently adopted a climate policy (the Global Warming Solutions Act, AB 32) that puts the state on track to strongly reduce emissions and minimize damage from climate warming. Regulations are currently being developed under this new law to determine how to meet the global warming pollution reduction targets of nearly 29% by 2020 and 80% by 2050 to which the state has committed.

Agriculture is responsible for only 8% of the state's greenhouse gas emissions, but it is disproportionately sensitive to climate change. Clearly, emission reductions must come from all over the world, but as the twelfth largest greenhouse emitter globally, the state is setting a strong precedent for other players to follow.

The wine industry is starting to recognize the issue of climate change on local, state, national, and international levels, which is essential to be proactive in developing response strategies. A sound strategy will involve both adaptation to the inevitable warming (for example, investments in new technology) and mitigation to reduce greenhouse pollution to leave open the widest array of options in the future.

Innovative local adaptation efforts include a new project of the Napa Valley Vintners to work with climate scientists to understand the historical climate of the region, and what this might imply for the future (see www.napavintners.com).

On the mitigation side, reductions in greenhouse gases can come from individual and business decisions about transportation, lighting, and building construction, or from national policies for incentives and large-scale energy systems.

The wine industry has the opportunity to contribute to mitigation efforts through attention to its own CO footprint, and as a leader for others to emulate. But because the direct environmental footprint of agriculture is a small fraction of emissions (8% in California), effective mitigation will have to involve political leadership and policy development. The wine industry has the potential to be an effective advocate for local, state, national, and international policies that can limit climate changes to the range consistent with sustaining a vibrant industry.

1. Arrhenius, S. 1986. "On the influence of carbonic acid in the air upon the temperature of the ground." The London, Edinburgh, and Dublin PhilosophicalMagazine and Journal of Science 41: 237-76.

2. California Agricultural Statistics Service. 2007. Grape crush report: Final 2006 crop, California Department of Food and Agriculture, Sacramento, CA.

3. California Energy Commission. 2006. Inventory of California greenhouse gas emissions and sinks, 1990-2004. Rep. CEC- 600-2006-013-SF, California Energy Commission, Sacramento, CA.