Barge and towboat traffic on the Upper Mississippi River was at a standstill after the navigation channel — through which about half of the nation’s grain exports pass — became clogged with sediment from floodwaters last summer.

Business leaders looking for a smart way to influence the most controversial questions in public life can do much worse than follow the example of Cargill and its former CEO, Greg Page, on the question of addressing climate change.

The reason you haven't heard that a high-profile executive like Page has become a climate change activist, is because, well, he really hasn't. He doesn't go on TV to demand passage of a new tax on carbon emissions, and he doesn't seem likely to start.

Instead all he's asking is that business managers make the risks inherent in a changing climate a regular part of their planning.

Page, who remains executive chairman of Cargill, calls his approach "starting in the middle." He noted that there's no shortage of loud voices at either end, and if climate change "believers" want to argue with the climate change "deniers," they can have at it.

Page would rather talk about taking steps now to make sure Upper Midwest farmers can see their grain continue to be shipped on river barges, as big swings in water levels brought on by extreme drought and excessive rain become more common. That's managing a risk.

And yes, this kind of thinking in business could be a very big difference maker on whether the public swings around to supporting action on the threat of climate change. Watch the business leaders, not what they are saying, but how they're investing their money. That should say quite a lot.

Page

In a conversation last week in his office at Cargill, Page explained that he wasn't exactly eager to join a climate change discussion when former Secretary of the Treasury Henry Paulson invited him to join the risk committee of a research project Paulson and two others had started.

Not that he doesn't find this topic to be important to Cargill. He sees very little for a corporate leader to gain by weighing in on a public policy issue that doesn't really touch the mission of the business, but climate change is close to home for his company.

Cargill plays in the food industry up and down the chain. What to grow, and where, is highly climate-dependent. And Cargill has also been assessing and managing risk for its entire 150 years in business.

His reluctance was mostly because farmers are the customers of Cargill, and Page said that the typical farmer hears "climate change" and jumps immediately to the threat of government regulatory overreach.

But regardless of one's views about climate change, Page thinks it's just plain irresponsible for anyone, at Cargill or a family farm, to look at a growing pile of scientific research on the topic and decide to do absolutely nothing different.

So Page joined Paulson's project, called Risky Business, though he explained that Cargill economists, crop scientists and other staffers spent more time on this than he did.

The result of some of their work can be seen in the project's most recent report, now out for a little over a week. This one focused exclusively on the risk of climate change here in the economy of the Midwest.

The report concluded that if we continue on our current path for carbon emissions, and without any adaptation, "by the end of the century the Midwest will likely see overall agricultural losses for corn and wheat of 11 percent to 69 percent across the region as a whole, with a one in 20 chance of more than an 80 percent decline."

In addition to the sobering idea that much of the Corn Belt may no longer be the Corn Belt, Page sees risks up and down the food production system. It's recently been possible, within the span of maybe 15 months, to see water so high that barges on upper Midwestern rivers will not fit under the grain loading spout and so low that loaded barges can get stuck on the bottom.

Page also recently learned that between 2012 and 2013, the planting date for crops varied 36 days from one year to the next, which means any sensible farmer looking ahead to the coming growing season can't assume anything based on the previous year.

And yes, he said, some farmers he's met are crabby about his involvement in climate change discussions. But in general farmers are more open than the public may realize to new thinking on the risks posed by a changing climate to their business. One example he cited was Tier IV emissions technology for new diesel tractors, and American farmers don't seem to gripe about that.

Inside a company like Cargill, Page said, once assessing the risks of a hotter climate becomes a normal part of business planning, it can affect all sorts of decisions. When it comes time to replace Cargill's animal handling buildings in southeastern Iowa, for example, maybe the roofs will need to be built with more insulation to mitigate some of the effects of a hot summer sun.

A better insulated roof, however, is a way for a company to react to a warmer climate. That approach is sure to frustrate climate change activists, who would probably much rather see Cargill joined at other big businesses to take big steps now to cut greenhouse gas emissions and make it less likely that the planet warms.

By Cargill's actions, however, it's interested in more than adapting to a warmer climate.

Its facility in Uberlandia, Brazil, is one example. The company burns a wood-chip fuel derived from local eucalyptus trees for 70 percent of the electricity and all of the heat needed at this plant.

Page is clearly interested in seeing fossil fuel use cut by businesses, but what he seems most interested in talking about is making sure the planet has enough to eat.

"When we first started talking with the group from Risky Business, 'adaptation' sort of struck them as the second cousin of this effort," he said, although it helped to add the idea of resilience to the discussion. "In food, adaptation and resilience has just got to be the focus, because you just don't want to be wrong."

The implications of being wrong about the effects of climate change on food production, he added, "are too big."

lee.schafer@startribune.com • 612-673-4302