Rodney Strong Wine Estates announced last month that it is now “carbon neutral.” The Sonoma County winery joins several in California, South America and New Zealand that, through conservation and investment in clean energy (by buying carbon credits), have reduced their carbon emissions enough to essentially zero out their contribution to greenhouse gases.

Wineries today tout their environmentalist credentials almost as much as their scores from influential wine critics. Their news releases gloat about certifications for sustainable or organic farming or glittering new solar power arrays more often than about the latest vintage release. Napa County police recently nabbed a ring of thieves who were sneaking onto winery grounds at night to pilfer valuable solar panels.

Winemakers are farmers, after all. They depend on the Earth, so it is not surprising that they would want to take care of it.

For Rodney Strong owner Tom Klein, the carbon-neutral status was just the winery’s latest step in environmental conservation.

“We started 15 years ago with the easy things: improving our recycling efforts, conserving water, running the winery more efficiently,” Klein said. “Then I saw Al Gore’s movie, ‘An Inconvenient Truth,’ and I really got the bug. It convinced me global warming is real.”

When the California-based Wine Institute endorsed sustainable wine growing early this decade, Klein hired a viticulture consultant to implement the new guidelines on reduced chemical use and fish-friendly farming, which uses cover crops to reduce runoff into streams and rivers. He converted the winery to solar power in 2003 and joined the Climate Registry, a nonprofit organization that helps businesses, families and governments reduce their carbon footprints.

Any winery uses a lot of electricity in temperature control for preserving the wines and buying and shipping bottles. But it can also get credit for the vineyards, which absorb carbon. Rodney Strong buys additional carbon credits through Pacific Gas&Electric and a program called Native Energy to offset its emissions that cannot be reduced or offset by its vineyards.

Carbon neutrality is already becoming a marketing buzzword for environmentally conscious wineries, above and beyond sustainable or organic viticulture. Parducci, in California’s Mendocino County, was the first U. S. winery to achieve carbon neutrality, in 2007. Cono Sur, a popular value-priced Chilean brand, also trumpets its carbon neutrality.

What effect does all this vine-hugging have on the quality of the wine?

“Nothing at all,” admits Dave Pearce, chief winemaker of Grove Mill winery in New Zealand’s Marlborough region. Grove Mill was the world’s first winery to achieve carbon neutrality, in 2006. For Pearce, carbon neutrality was about doing the right thing, “and good things happen to those who do good things,” he said. Grove Mill’s efforts included changing its international shipping by using lighter bottles with a shape that could fit more efficiently on a pallet and in a shipping container.

“Carbon neutrality requires a mind shift: from thinking of money as a measure of good to thinking of carbon as a measure of good,” Pearce said. “And it’s not just carbon, but all greenhouse gases, including nitrogen and methane.”

Klein, of Rodney Strong, expressed a similar sentiment. “If you only look on the return on investment, you’ll never arrive at the right decision,” he said. “You work on business sense, but you have to do the right thing. The planet has to live, and if you aren’t willing to make changes, why would others?”