VALLE DE GUADALUPE, BAJA CALIFORNIA, MEXICOAt first glance, the neat rows of wiry grapevines planted in a pinwheel at the Viñas del Tigre vineyard in Baja California don't seem remarkable. But to Aldo Quesada, the grower and winemaker, the rows are a map to the future.

On one side of the pinwheel, tempranillo, merlot, granache, and other classic wine grapes look withered and anemic. Over the past few years they have been baked by unprecedented heat waves and parched by record-breaking drought—the brutal new normal climate conditions here at the southernmost tip of North America’s wine-growing range.

But one row looks different. Quesada's misión grapes, descendants of the first grape varietal carried to North America by Spanish missionaries 500 years ago (and called "mission" in English), are