It is true that there is uncertainty about the timing and magnitude of these risks and many others. But those who claim the science is unsettled or action is too costly are simply trying to ignore the problem. We must see the bigger picture.

The nature of a crisis is its unpredictability. And as we all witnessed during the financial crisis, a chain reaction of cascading failures ensued from one intertwined part of the system to the next. It’s easy to see a single part in motion. It’s not so easy to calculate the resulting domino effect. That sort of contagion nearly took down the global financial system.

With that experience indelibly affecting my perspective, viewing climate change in terms of risk assessment and risk management makes clear to me that taking a cautiously conservative stance — that is, waiting for more information before acting — is actually taking a very radical risk. We’ll never know enough to resolve all of the uncertainties. But we know enough to recognize that we must act now.

I’m a businessman, not a climatologist. But I’ve spent a considerable amount of time with climate scientists and economists who have devoted their careers to this issue. There is virtually no debate among them that the planet is warming and that the burning of fossil fuels is largely responsible.

Farseeing business leaders are already involved in this issue. It’s time for more to weigh in. To add reliable financial data to the science, I’ve joined with the former mayor of New York City, Michael R. Bloomberg, and the retired hedge fund manager Tom Steyer on an economic analysis of the costs of inaction across key regions and economic sectors. Our goal for the Risky Business project — starting with a new study that will be released this week — is to influence business and investor decision making worldwide.

We need to craft national policy that uses market forces to provide incentives for the technological advances required to address climate change. As I’ve said, we can do this by placing a tax on carbon dioxide emissions. Many respected economists, of all ideological persuasions, support this approach. We can debate the appropriate pricing and policy design and how to use the money generated. But a price on carbon would change the behavior of both individuals and businesses. At the same time, all fossil fuel — and renewable energy — subsidies should be phased out. Renewable energy can outcompete dirty fuels once pollution costs are accounted for.

Some members of my political party worry that pricing carbon is a “big government” intervention. In fact, it will reduce the role of government, which, on our present course, increasingly will be called on to help communities and regions affected by climate-related disasters like floods, drought-related crop failures and extreme weather like tornadoes, hurricanes and other violent storms. We’ll all be paying those costs. Not once, but many times over.