Would there be a great outcry worldwide, demanding that reservoirs be drained and hydro dams shut down? Of course not. Do you think we are superstitious savages? We are educated, civilised people, and we understand the way that risk works.
OK, another thought experiment. Suppose that three big nuclear power reactors were damaged in that same monster earthquake, leading to concerns about a meltdown and a massive release of radiation - a new Chernobyl. Everybody within a 20km radius of the plant was evacuated, but in the end there were only minor leakages of radiation, and nobody was killed.
Well, that was a pretty convincing demonstration of the safety of nuclear power, wasnt it? Well, wasn't it? You there in the loincloth, with the bone through your nose. Why are you looking so frightened? Is something wrong?
In Germany, tens of thousands of protesters demonstrated against nuclear power last Saturday, and Chancellor Angela Merkel suspended her policy of extending the life of the country's nuclear power stations until 2036.
She conceded that, following events in Japan, it was not possible to "go back to business as usual," meaning that she may return to the original plan to close down all 17 of Germany's nuclear power plants by 2020.
In Britain, energy secretary Chris Huhne took a more measured approach: "As Europe seeks to remove carbon-based fuels from its economy, there is a long-term debate about finding the right mix between nuclear energy and energy generated from renewable sources ... The events of the last few days haven't done the nuclear industry any favours." I wouldn't invest in the promised new generation of nuclear power plants in Britain either.
And in the United States, Congressmen Henry Waxman and Ed Markey (Democratic), who co-sponsored the 2009 climate Bill, called for hearings into the safety and preparedness of America's nuclear plants, 23 of which have similar designs to the stricken Fukushima Daiichi plant in Japan.
The alleged nuclear renaissance of the past few years was always a bit of a mirage so far as the West was concerned. China and India have big plans for nuclear energy, with dozens of reactors under construction and many more planned. In the United States, by contrast, there was no realistic expectation that more than four to six new reactors would be built in the next decade, even before the current excitements.
The objections to a wider use of nuclear power in the United States are mostly rational. Safety worries are a much smaller obstacle than concerns about cost and time: nuclear plants are enormously expensive, and they take the better part of a decade to license and build.
Huge cost overruns are normal, and government aid, in the form of loan guarantees and insurance coverage for catastrophic accidents, is almost always necessary.
The cost of wind and solar power is steadily dropping, and the price of natural gas, the least noxious fossil-fuel alternative to nuclear power, has been in free fall. There is no need for a public debate in the United States on the desirability of more nuclear power: just let the market decide. In Europe, however, there is a real debate, and the wrong side is winning it.
The European debate has focused on shutting down existing nuclear generating capacity, not installing more of it. The German and Swedish governments may be forced by public opinion to revive the former policy of phasing out all their nuclear power plants in the near future, even though that means postponing the shut-down of highly polluting coal-fired power plants. Other European governments face similar pressures.
It's a bad bargain. Hundreds of miners die every year digging the coal out of the ground, and hundreds of thousands of other people die annually from respiratory diseases caused by the pollution created by burning it. In the long run, hundreds of millions might die from the global warming that is driven in large part by greenhouse emissions from coal-fired power plants. Yet people worry more about nuclear power.
It's the same sort of mistaken assessment of risk that caused millions of Americans to drive long distances instead of flying in the months just after 9/11. There were several thousand excess road deaths, while nobody died in the airplanes that the late lamented had avoided as too dangerous. Risks should be assessed rationally, not emotionally.
And here's the funny thing. So long as the problems at Fukushima Daiichi do not kill large numbers of people, the Japanese will not turn against nuclear power, which currently provides over 30% of their electricity and is scheduled to expand to 40%. Their islands get hit by more big earthquakes than anywhere else on Earth, and the typhoons roar in regularly off the Pacific. They understand about risk.
• Gwynne Dyer is an independent London journalist.
