It was 8 degrees in Minneapolis on a recent January day, and out on Interstate 394, snow whipped against the windshields of drivers on their morning commutes. But inside the offices of Cargill, the food conglomerate, Greg Page, the company’s executive chairman, felt compelled to talk about global warming.

“It would be irresponsible not to contemplate it,” Mr. Page said, bundled up in a wool sport coat layered over a zip-up sweater. “I’m 63 years old, and I’ve grown up in the upper latitudes. I’ve seen too much change to presume we might not get more.”

Mr. Page is not a typical environmental activist. He says he doesn’t know — or particularly care — whether human activity causes climate change. He doesn’t give much serious thought to apocalyptic predictions of unbearably hot summers and endless storms.

But over the last nine months, he has lobbied members of Congress and urged farmers to take climate change seriously. He says that over the next 50 years, if nothing is done, crop yields in many states will most likely fall, the costs of cooling chicken farms will rise and floods will more frequently swamp the railroads that transport food in the United States. He wants American agribusiness to be ready.

Mr. Page is a member of the Risky Business Project, an unusual collection of business and policy leaders determined to prepare American companies for climate change. It’s a prestigious club, counting a former senator, five former White House cabinet members, two former mayors and two billionaires in the group. The 10 men and women who serve on the governing committee don’t agree on much. Some are Democrats, some Republicans.

Even when it comes to dealing with climate change, they have very different perspectives. Some advocate a national carbon tax, some want to mandate companies to disclose their climate risks. Mr. Page suggests that the world may be able to get by without any mandatory rules at all. Some members want to push investors to divest from fossil fuel companies. Several favor construction of the Keystone XL pipeline, while one member has spent more than $1 million lobbying to stop it. But they all do agree on one issue: Shifts in weather over the next few decades will most likely cost American companies hundreds of billions of dollars, and they have no choice but to adapt.

The committee started in June as a way to promote a study that it commissioned, “Risky Business: The Economic Risks of Climate Change in the United States.” But it has since evolved into a loose network of missionaries who publicize the report’s ominous data far and wide, in talks at the Clinton Global Initiative conference, briefings with the American Farm Bureau Federation and breakfast meetings with local chambers of commerce.

On Jan. 23, the group released the second chapter of the Risky Business project, focused on the effects on the Midwest: “Heat in the Heartland.” A report on California is next. With $1.7 million in grants from the MacArthur Foundation and others, the group is hiring a full-time staff.

The group is led by three men: Tom Steyer, the hedge fund billionaire whose super PAC spent $73 million last year attacking Republicans who denied climate change and promoting awareness of the issue; Henry M. Paulson Jr., the former chief executive of Goldman Sachs and the Treasury secretary under President George W. Bush; and Michael R. Bloomberg, New York City’s former mayor and the billionaire founder of the financial information company Bloomberg L.P. Each spent $500,000 to commission the Risky Business research and each has his own particular goals for the initiative, all of which would be served by making the climate threat feel real, immediate and potentially devastating to the business world.

Mr. Paulson wants companies to implement and regulators to enforce disclosure rules regarding climate risk and carbon emissions for publicly traded companies. Mr. Bloomberg views the work as a way to spur city governments and local businesses to work together on climate issues and not “kick the can down the road,” he said. Mr. Steyer sees the dollars-and-cents research as a way to neutralize conservatives’ arguments that environmental regulation always hurts business.

“One side argues morality and polar bears, and the other side argues jobs,” Mr. Steyer said. “You’re never going to win with polar bears.”

Embracing Adaptation

To understand how the Risky Business Project came to be, it’s helpful to look at how the climate change battle has been waged over the years. In the early days, discussion was focused on fixing the problem and staving off disaster. This has been the strategy environmentalists have used to respond to all sorts of risks for years: Scientists identify the harm, publicize it, debate with the responsible industry and expect legislators to take action.

The very idea of thinking about how to adapt to drastic environmental changes was basically considered taboo, an acknowledgment of defeat. “Earlier on, you wouldn’t use the ‘A’ word in polite conversation,” said Henry D. Jacoby, a professor at the Sloan School of Management at M.I.T. and a climate policy researcher — the “A” word being “adaptation.” “People thought you weren’t serious about mitigation. ‘Oh, you’re giving up.’ “

But climate change defied that playbook. There was no immediate crisis to point to — no bird eggs laced with DDT, no acid rain corroding city monuments. There was no one industry to target or overwhelming constituency to push legislators.

“The rationalist, evidence-driven, faith in the political process approach to solving environmental problems has been really effective in many realms,” said Hal Harvey, who advised the Risky Business group and is chief executive of Energy Innovation, a green policy firm. “But it has done bupkis for climate change.”

Indecision and indifference have prevailed instead. A majority of Americans in 2014 surveys by Pew Research and Gallup acknowledged climate change was happening, and 83 percent of Americans say that without emissions reductions, global warming will be a problem in the future, according to a January survey conducted by The New York Times, Stanford University and the environmental group Resources for the Future. But in survey after survey, those same Americans rank climate change at or near the bottom of pressing issues, far behind jobs, the economy and health care.

In the meantime, powerful lobbies, including fossil fuel groups, the U. S. Chamber of Commerce and the National Association of Manufacturers, stand in the way of regulation. Climate change has become a partisan issue — a cause for conservatives who fear government overreach.

It was in this context that in November 2012, Mr. Steyer convened a meeting at his Pescadero, Calif., ranch. The month before, he had stepped down from running his hedge fund, Farallon Capital Management, to devote himself to the environment. He wanted to devise a way to fight climate change more effectively, and he had assembled some highly regarded thinkers to help him brainstorm. Attendees included the environmentalists Bill McKibben and Mr. Harvey, and the political strategists John D. Podesta and Chris Lehane.

As cattle grazed on native grasses outside, and a water-filtering eco-sculpture burbled on the patio, the participants tossed ideas around the kitchen table. Mr. McKibben discussed his fossil fuel divestment campaign. Others suggested stoking a social media groundswell. One suggested making life hard for climate change-denying politicians (the latter idea became the basis for Mr. Steyer’s super PAC, NextGen Climate Action).

While Mr. Steyer was devising his political strategy, the staff at Next Generation, his nonprofit group, were at work trying to solve another critical question: How do you make climate change feel real and immediate for people?

Kate Gordon, senior vice president of Next Generation, Mr. Steyer’s nonprofit, whose mission focuses on climate change and improving the economic prospects of families, found inspiration in a British report called the Stern Review, published in 2006. It was an economic analysis, sponsored by the British government, which examined all the costs of climate change, eventually concluding that the price of curbing global warming paled compared with the costs of doing nothing.

Ms. Gordon pitched Mr. Steyer on an American version — what would become the Risky Business report. It would be a way to discuss in a practical, dollars-and-cents way how businesses would have to adapt to climate change, while also making a clear case for taking action to mitigate the coming environmental crises. He liked what he heard.

The team wanted to bulletproof the report, so that public discussion would not become a politicized debate about their methods or their messengers. So they contracted an economic research firm, the Rhodium Group. They also reached out to Mr. Paulson, a Republican, and Mr. Bloomberg, an independent, to see if they would co-sponsor the study and help form a bipartisan committee. Both agreed, and over the following summer and fall, the three enlisted other leaders through their personal networks.

Mr. Paulson called Mr. Page, whom he knew from the Latin America Conservation Council. Through a contact of Ms. Gordon’s, they signed up Henry G. Cisneros, the former housing and urban development secretary under President Bill Clinton and now a real estate developer. Mr. Steyer called Robert E. Rubin, the former secretary of the Treasury under President Clinton and a longtime friend and mentor from their days at Goldman Sachs.

For some, like Mr. Cisneros, it was the first public involvement with climate change. For Mr. Rubin, it marked a change in perspective. During his time in the Clinton administration, the Treasury Department argued the aggressive emissions reductions proposed in the Kyoto Protocol would harm the economy. Mr. Rubin wouldn’t make that argument now. “I think it’s the existential threat of our day,” he said. “Once you see it as having catastrophic impact, any economic argument follows that, because you’re not going to have an economy.”

Mr. Page’s involvement with the committee was the subject of “a fairly energetic debate” within Cargill, he said. In the end, he decided to participate because the study was an analysis of potential outcomes, not one that purported to make concrete predictions or specific policy recommendations. He also figured it would be best to be involved in any report that planned to say something about his industry, especially one with such prominent backers. He didn’t want them “using the Risky Business report to terrify the U.S. population about its food supply,” he said.

Cargill “hasn’t weighed in” on the regulatory debate, Mr. Page said, because the company prefers to examine rules case by case. (“Is cap-and-trade per se bad? No. Is the way it was administered in Europe ineffective? Absolutely,” he said). Unlike other committee members, he seems to favor voluntary commitments to reduce greenhouse gases. Generally, the company is opposed to any regulation that will force it to shut plants, retire equipment or otherwise “destroy fixed capital,” he said.

In May 2014, the committee members gathered at the Bloomberg Philanthropies offices in Manhattan to hear two of the authors commissioned by the Rhodium Group — Robert E. Kopp, a climate scientist at Rutgers University, and Solomon M. Hsiang, an economic policy researcher at the University of California, Berkeley — present their findings. Among their conclusions if the status quo persisted: Climate change would increase energy demand in Texas by between 3.4 and 9.2 percent by midcentury. Crop yields in Missouri and Illinois would face a 15 percent decline over the next 25 years. And in the Northeast, annual property damage from severe storms — from hurricanes to blizzards — would likely increase $11.1 billion, to a total of $15.8 billion by the end of the century.

Of all the members, Mr. Rubin is most preoccupied with the so-called tail risks — low-probability events where the most damage is done. Mr. Page, on the other hand, prefers to prepare for the most likely outcomes.

At the meeting in May, some of those differences were discussed. As the report was being put together, Cargill scientists had argued that the agriculture industry was well prepared to adapt to changes. Mr. Bloomberg was skeptical, Mr. Page recalled. During a break, Mr. Bloomberg took Mr. Page aside and peppered him with questions: Do these technologies exist? Or are you saying they will someday — “as in, we know there will be a cure for cancer, but we have no idea when or how?” Mr. Page said he respected Mr. Bloomberg’s diligence in seeking answers, although he maintained that adaptation was more a matter of execution for the food industry, not research and development. “But the guy’s a good reporter, let’s put it that way,” Mr. Page said.

Light Touch With the Message

Mr. Paulson works on the upper floors of a skyscraper in downtown Chicago, with a conference room overlooking the Chicago River. In January, the wind across it is cutting, and ice floes drift along the sides. By midcentury, if the Risky Business report is right, those ice floes will be gone.

When Mr. Paulson speaks to local groups, he makes sure to bring data from the report tailored to their county. “I’m not just having an abstract conversation about climate being this big risk. I can say, ‘Let me tell you!’ ” he said, slapping the table. “Here’s what this is going to mean to you, your industry and your family. Suddenly people are interested.”

Mr. Cisneros says he uses a soft touch when speaking to real estate groups, so that people don’t feel lectured to. “I say, ‘This has not been my highest priority either, but it’s got my attention, and I want to share it with you,’ ” he said. He warns audiences to budget for spiraling insurance premiums in coastal states like Florida, and to keep in mind that in drought-prone regions like California’s Central Valley, water permits may become hard to acquire.

Mr. Page treads especially lightly when addressing farmers’ groups, as he says they have been conditioned to think of global warming as a liberal euphemism for more regulation. Instead of coming right at the issue, he takes a circuitous route. “I ask simple questions: ‘Would you like universities to suspend research on seeds that grow in higher temperatures? Of course not! That’s all I’m saying!’ ” he said, raising his hands defensively. “You get people to acknowledge that they, too, have anxieties. It’s a micro-acknowledgment, not a macro-acknowledgment.”

Through this kind of education, several committee members hope to recruit business leaders to the side that helps, not hinders, the fight against climate change. “The whole point of all of this is that it can be mitigated,” Mr. Paulson said. “The enemies of what we’re trying to do are short-termism and a sense of hopelessness. But if we act soon we can avoid the worst outcomes and adapt.”

Even so, the committee members seem to have a long road ahead of them.

After meeting with Mr. Page, Jon Doggett, executive vice president of the National Corn Growers Association, said he was skeptical that the report would influence farmers much. His members need near-term incentives to cut greenhouse gases — immediate cost savings, government incentives and so forth, he said.

“Are we going to reduce greenhouse gas emissions today because we believe there’s an economic benefit 15 years from now? That’s way too hypothetical for a family-owned and operated business that has to make a payment this year,” Mr. Doggett said. “The banker doesn’t get paid in hypothetical dollars.”

Dale Moore, executive director of public policy for the American Farm Bureau Federation, which lobbies in Washington on behalf of farmers and ranchers, said he agreed with Mr. Page that climate seemed to be in a “more extreme cycle” and that agribusiness would do well to develop hardier seed strains. But the group’s members remain skeptical that humans cause climate change. They are part of a consortium opposing the Environmental Protection Agency’s new proposed rule limiting coal-fired power plants.

But not all business groups feel this way. The Seattle Metropolitan Chamber of Commerce parted ways with the national Chamber of Commerce in 2011 specifically because the views of Seattle members on climate change differed so drastically with the sort of climate-denying statements the national group was making. “We were hosting clean technology conferences,” said Maud Daudon, president of the group, “and they were issuing statements that came from an entirely different place.”

Bit by bit, the Risky Business Project’s committee members hope to turn the tide, bringing Congress around to the way that a majority of Americans feels. “We’ve made progress on things like civil rights, smoking, gay marriage and other things that seemed impossible to move when businesspeople joined the silent majority,” said Mr. Cisneros. “Congress tends not to act until the broad mainstream, including business, is aboard.”

And if business feels the pain in its wallet, it will feel the heat to act, even on the coldest of days.