Just a few days into this year’s harvest at the Château de Saint-Martin, a vineyard tucked into a valley in inland Provence owned by the same family since 1740, estate owner Adeline de Barry spotted one of her worst fears playing out on the vines: leaves browned at the edges surrounded by bunches of dried-out grapes, some of them irrevocably spoiled.

Putting a quick tour of the property on hold, she crouched down under the sweltering sun and ran her hands through the damaged vines. “They’re suffering,” she told me with a sigh. “This is exactly the concern.”