How risky is offshore oil?

Drilling for oil offshore looks a lot riskier now than it did 10 days ago, and that could well affect the energy debate for years to come. The fallout from the Deepwater Horizon oil-rig explosion is a perfect example of how a catastrophic event rearranges our finely tuned systems for weighing risks and benefits.

"It's a huge story," risk analyst David Ropeik told me. "Oil is leaking into the sea from the ocean floor all the time, massive amounts, but that's spread out and it's not as concentrated. It's OK if nature leaks stuff into the ocean, but this is man-made, and man-made risks are scarier than natural risks."

As oil began washing up on the Louisiana coast, President Barack Obama put a hold on new offshore oil leases until safety questions are resolved. The move came just a month after Obama cleared the way for expanded offshore drilling in 2012. Now, some commentators say the president should reverse course yet again.

Ropeik delves into how events and emotions affect our perceptions of risk in a new book, "How Risky Is It, Really?" - and he says right now is exactly the wrong time to reconsider energy policy. "Decisions such as what to do about offshore drilling are poorly made at highly emotional moments like this," he told me.

In that context, Obama's decision to hold off on new offshore drilling leases sounds sensible. It has no practical impact for the time being, and puts off any fresh policy decisions until more is known about this particular incident as well as the more general safety status for offshore exploration. (The record has not been spotless, but statistics show that there's been nothing else like this month's offshore-oil spill over the past 15 years.)

Ropeik said catastrophic events tend to distort the way we judge the overall risk associated with a particular behavior - a phenomenon he calls the "perception gap."

"When a large-scale event like the oil spill comes along, the scale of it alone magnifies how scary it feels," he said - and that scariness is factored into future policy decisions, often disproportionately. "We demand protection from what we're afraid of," Ropeik observed.

One example of that has to do with how the Three Mile Island nuclear plant accident in 1979 affected the power industry. Nuclear power virtually became a taboo subject. Some of the concerns were justified, and addressed. But it's taken 30 years - and a countervailing fear of global warming caused by fossil fuels - to get policymakers thinking seriously about nuclear power again.

"I reported extensively on nuclear power issues in New England, and I wish I knew then what I know now about the danger," Ropeik, a former TV journalist, says in his book. "The risk is real, but it is not nearly the threat I said it was in much of my reporting. So, my apologies for having contributed in my small way to a societal perception gap that has significant consequences for public and environmental health."

Another classic example of the perception gap at work came after the 9/11 terror attacks, when some travelers changed their habits to drive rather than fly to their destinations. "Driving felt safer, control makes things feel safer, but many of those people probably already knew what they needed to know - that flying is safer," Ropeik said.

At this point, Ropeik doesn't dare suggest what should be done about the offshore-drilling issue at this point. "But I do dare suggest that risk perception matters so much that we are acutely sensitive to things that can threaten our health and safety," he said.

He suggests some easy steps to fill in the perception gap - about offshore drilling as well as the other risks we might face in everyday life.

"The basic message is that we have evolved an instinctive system for perceiving danger, which worked fine when risks were simple but doesn't work so well now when risks are more complex," he said. "That can make you more afraid than you should be, or not afraid enough. The gap itself is a risk, and realizing that is the first step toward thinking about any risk a little more clearly."

One way to reduce your fear about a particular problem is to try to get involved in bringing about a solution, even if it's not immediately clear how much impact your involvement will have. Louisianans in the fishing industry are taking advantage of that strategy by getting some training in oil spill cleanup.

Even if you can't be on the scene, there are still ways to reduce your perception gap. Fill in your knowledge gap by getting more information from sources you trust, "and that doesn't mean sources you agree with," Ropeik said. His most important piece of advice is something that's highlighted in "The Hitchhiker's Guide to the Galaxy": DON'T PANIC.

"One of the easiest things to do is give yourself a couple of minutes to think things through," Ropeik said.

Have you thought things through? If so, feel free to add your comments about the oil-spill crisis and its implications for future energy policy.

More about the spill and its implications:

• See the spill from space 
• Oil spill updates from Field Notes blog
• This spill is the 'bad one' that experts feared
• Newsweek: 'Three Mile Island for offshore oil'? 
• Environment coverage at msnbc.com

Check out the essay that Ropeik wrote for msnbc.com in 2001 about post-9/11 "fear factors," plus The Washington Post's review of Ropeik's book as well as Robert Wuthnow's "Be Very Afraid."

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