(NPR) - Prime California wine country areas like the Napa Valley could soon be facing rising temperatures, according to climate change studies. So some wineries are thinking of switching to grapes that are better suited to a warmer climate. But when vineyards have staked their reputations on certain wines, adapting to climate change is a tough sell. The specific type of grape, or varietal, is how most of us think about wine. At one recent meeting of the San Francisco Wine Lovers Group, for instance, members listed pinot noirs, sauvignon blancs or cabernets among their favorite kinds of wine. All are well-known varieties grown in the California region.