Worlwide Wineries

[Wines & Sheperds]

I'll take a stab at this question.
According to the latest U.S. Census there are ~4,700 wines in the U.S.

The U.S. is aprroximately 5,984,685 square miles.

The surface area of the earth is roughly 197,353,667 square miles of which 65,784,566 is land.

If you assume 2/3 of the land is suitable for growing grapes ~+/- 15 degrees from poles is too cold for grapes you get an approximation of 43,417,807 suare miles of growing region.

If you scale the number of wineries in the US to the size of the growing region in the world you get a number slightly larger than 34,000.