Speaking at the Beautiful South tasting, Dr Fernando Santibáñez of the University of Chile said grape-growing could become impossible in warmer regions such as the Napa Valley and Spain as the earth warms up.
But the southern hemisphere looks better placed to weather the storm, he said.
"If the temperature rises by 2°C white wine regions will become red wine regions in the south, but in the north it could be a bit more dramatic," Santibáñez said. "We will face a big challenge of how to adapt to this new situation."
Mediterranean regions which are not cooled by Atlantic currents could see the most dramatic changes in temperature.
In contrast, in Chile, Argentina and South Africa cold ocean currents and cold air coming down from the Andes at night will help stabilise temperatures.
The southern hemisphere is made up of 90% water so it has been less severely hit by global warming so far, Santibáñez added.
He said: "The southern hemisphere has unique climatic conditions to guarantee a continuous production of high quality wines even in times of climatic change."
But he was hopeful that technological advances would help the world's classic wine regions to keep production going.
The Beautiful South tasting brings together more than 300 wineries from Chile, Argentina and South Africa at London's Olympia this week.
It is the first time the three countries have held their annual tastings as a joint event.