There’s lots to like about the local food movement. Fresh, local seasonal fruits and vegetables taste better. Farmers markets enhance the vitality of city life. Cutting “food miles” reduces carbon pollution, and money spent by locavores stays with nearby growers.

Alberto Weisser, the CEO of Bunge, a $60-billion a year global agribusiness and food company is, not surprisingly, unimpressed. His global business is built on trade. Bunge operates in 40 countries. It charters 150 ships a day to carry agricultural products. Only one terminal to export grain from the US has been built in the past 25–and it was built by Bunge, near the Columbia River in Washington, to ship grain from the US to Asia.

But Weisser, who spoke on Dec. 11 at the Johns Hopkins School of Advanced International Studies in Washington, made a good case that an expansion of global trade  will be the best way to feed the world in a sustainable way, as well as increase the incomes of millions of poor farmers. Like it or not, he said, the world is more interdependent than ever.

Alberto Weisser

“When it comes to agriculture, no country is an island–even the ones that are islands,” Weisser said, displaying a flash of humor in what was otherwise a sober look at the issue of global food security. “I remain firm in my belief in free markets, and what they, and only they, can deliver.”

Government, he acknowledged, has a vital role to play in food systems. It needs to assure food safety. It also needs to manage environmental impacts.

Climate change, he said, is an undeniable reality for Bunge. Northern climates are warming.

“The fact that the Ukraine grew two and a half million tons of corn–that’s news,” Weisser said. “We are growing soybeans all the way into Canada.” He said the company has closed 20 “crush plants” — those are facilities that turn seeds into oils — because “they were in regions that weren’t relevant anymore.” Who knew?

But the uncertainties created by climate change argue for global supply chains. This summer’s drought, for example, led to disappointing yields for US farmers. “South American farmers are picking up the slack by shifting to corn or soybeans,” he said.

The local-food movement, moreover, ignores the inconvenient fact that there are places where it’s all but impossible for people to grow their own food.

“Asia, for example, has 55% of the population but only 25% of the agricultural area,” Weisser said. And more than 450 million people live in desert-like conditions in Northern Africa and the Middle East.

Morocco, meantime, used to produce its own wheat until the government there encouraged farmers to grow vegetables and olive oil. It now exports those products to Europe and imports wheat from Ukraine–and the result is that everyone is better off, as David Ricardo might have anticipated.

“Trade has been the most powerful engine for economic development in the world’s history,” Weisser said. “We need the ability to grow commodities where it makes the most sense to grow them, and then move them wherever they need to go.”

This is by no means a widely accepted truth, as he noted.

“Globally, the flow of trade is impeded or stopped by too many obstacles,” Weisser said. “The temptation to retreat from the world, build a wall and bolt the door is profound. We see it every day.”

He didn’t cite specific examples but, sticking close to home, the US has tariff barriers against imported sugar that protect local growers and cost consumers and taxpayers millions. The US has also flooded the world with subsidized cotton, damaging growers in poor countries, particularly west Africa, as the UK’s Glenys Kinnock argued last year in The Guardian.

None of which means you should drop your CSA or abandon the local farmers’ market. But let’s not worry too much about food miles or food sheds either. As Weisser put it: “Interdependence is the most fundamental fact of our era.”