A small French revolution in wine is taking shape.

It’s going on in Bordeaux, the world’s most famous wine region, which has come to the realization that it must prepare for and adapt to climate change now, if not yesterday.

So the two biggest appellations in the region — Bordeaux and Bordeaux Superieur — have just been granted permission by the French government to do something that, until recently, was unthinkable. They will be permitted to use non-Bordeaux grapes in their wines.

Bernard Farges, president of the Bordeaux and Bordeaux Superieur syndicate, told me and a few other visiting journalist this week that the change will take effect with the 2021 vintage.

Now don’t expect them to start growing Pinot Noir and Chardonnay, the signature grapes of Burgundy, and call them Bordeaux. The idea is not to infringe on the identify, or sovereignty, so to speak, of any other wine region.

The “accessory grapes,” as Farges described them, will be chosen next month, and a maximum of 10 reds and 10 whites will be permitted.

Among the reds under consideration: Marselan, a cross between Cabernet Sauvignon and Grenache; Castets, an obscure grape grown in southern France; the well-known Touriga Nacional from Portugal; Vinaho, another Portuguese variety, used in Port; and Arinarnoa, a Bordeaux-bred grape that’s a cross between Cabernet Sauvignon and Tannat.

Possible white grapes include Petit Manseng, grown in southwest France, and the familiar Albarino of Spain and Portugal.

The grapes being considered are generally late-ripening varieties, Farges noted, unlike, say, Merlot, which ripens relatively early and may be particularly susceptible to over-ripening and higher sugar and alcohol levels. “The idea is to see how they ripen in a situation of global warming,” he said.

There will be strict conditions for their use. Each property will be limited to growing the new grapes in just 5 percent of its vineyards. And in any given wine, the new varieties won’t be permitted in more than 10 percent of the blend.

Interestingly and perhaps controversially, the grapes won’t be listed on the labels, a decision possibly aimed at preserving the identity of Bordeaux as it tentatively accepts “outsiders.” This comes just as more Bordeaux bottles have listed the traditional varieties like Cabernet, Merlot, and Sauvignon Blanc in recent years, making it easier for consumers to know what they’re drinking.

The new blueprint also includes an environmental component, aimed in part in cutting back on still-widely-used chemical treatments. Weed killers will no longer be permitted between vineyard rows (where you can walk), though they will still be allowed between the vines themselves.

It’s all a rather bold move for the appellations, setting a precedent — and a challenge — for the rest of Bordeaux.