People take sensible precautions when the risk is high. Ask a roomful of people if they have fire insurance. Almost all will raise a hand. Ask how many have had a fire in the last ten years, and almost none will respond. Yet people pay for insurance because, should a fire happen, they could lose everything — and still have to pay off the mortgage. But insurance only works when losses are isolated or occur in small batches, not when they synchronize into major disasters.

Uncertainty is another matter. With climate uncertainty, insurance companies will simply stop insuring some things, such as coastal real estate in Florida, making it difficult to get a mortgage. Those with money to loan worry about getting it back and will demand high interest rates as things become too unsettled.

Countries that innovate early get the new jobs, developing an economic edge over the C-free laggards that end up having to later import the technology. We need to innovate in a hurry and, considering our reputation for technological innovation, it's odd that the U.S. has fallen so far behind, on almost all fronts, when it comes to clean sources of energy that avoid dumping CO2 into the air.

• Many U.S. geothermal installations are imported from Israel and the major bank of Iceland helps to finance them. Though the Hot Rock Energy concept was invented in 1972 at Los Alamos, the action is now in Europe and Australia for what promises to be the electricity source with the lowest footprint.
• For 30 years, the U.S. avoided new nuclear power plant construction and instead built coal- and gas-fired plants for generating electricity. The French and Japanese are now the most experienced at building nuclear power plants. The French electricial utility will help build, and is a major investor in, the new U.S. nuclear plants now in the pipeline.
• The Germans have become the prominent innovators in "green" buildings.
• The Japanese and the Germans have more experience with solar power panels, though innovative thin-film photovoltaic from the U.S. is now coming on the scene.
• Think of wind turbine innovations and Spain, Denmark, and Germany will come to mind. To my surprise, there are now Italian windmills back home in Kansas! The largest Italian utility company is building a big wind farm near Hayes, Kansas to sell clean electricity to the coal-dependent American Midwest.

One reason we have a standing army is in case we are surprised. Now risk means we must provide something similar for climate surprises. We need the resilience to bounce back when something unexpected hits.

We also must have a good safety margin. We routinely have safety margins in support strength or fire resistance. No architect would design a stadium without calculat­ing the weight of the fans packing those bleachers — and then, for safety, doubling the number. Actually, it's the noncritical components that have a safety factor of two. For components whose failure could result in substantial financial loss, serious injury, or death, a safety factor of four or higher is common. Yes, that's more ex­pensive, one reason why building collapses are common in countries where building inspectors can be bribed to ignore skimping on the materials.

For climate protection, we need a safety margin in schedule because of the risk of something unexpected happening at a time when we lack maneuvering room. Our response needs to make a lot of progress up front, just as insurance against something as unexpected as, say, a fire in a rain forest. Climate change has a very high procrastination penalty that just grows and grows with each passing year of inaction — rather like what happens if you don't pay off your credit card. But for climate, there is no such thing as a fresh start from bankruptcy.

We've only got one habitable planet and we dare not shave our margins.

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William H. Calvin is professor emeritus at the University of Washington in Seattle and the author of fourteen books, including A Brain for All Seasons: Human Evolution and Climate Change, also published by the University of Chicago Press.