If, as I think almost certain to be the case, the environmental movement made a grave mistake in opposing nuclear power, the question naturally arises about what else the greens may have got wrong.
First, it is worth reminding ourselves of some of the things environmentalists got right, and for which humanity owes them a major debt of thanks. Climate change is top of the list; acid rain, too, now largely under control in North America and western Europe. The ozone layer also qualifies as a disaster mostly avoided, thanks to determined campaigning.
In all these areas environmentalists were successful because they followed science - both in understanding the dangers and designing solutions. It is where greens part company from science, as with nuclear power, that problems arise. I have now concluded that all the main objections raised against nuclear power are bogus, or overhyped, or solvable, yet the established environmentalist position - because of a herd mentality as well as deeply held ideology - remains opposed. As a result of three decades of successful anti-nuclear campaigning, tens of billions of tonnes of carbon have accumulated in the atmosphere, thanks to proposed nuclear plants being replaced by coal.
Admitting mistakes is difficult, especially when one's claimed position is the moral high ground. Although for years I believed in the anti-nuclear cause, I was never an active anti-nuclear campaigner. Genetic engineering, on the other hand, was something I spent years of my life campaigning against. And yet here, too, a science-led assessment of the likely risks and benefits suggests that I was wrong.
There is, for example, zero evidence that any genetically modified foods in existence today pose a health risk to anyone. Millions of people in the US and Canada have eaten GM corn and soya for years now. As the leading botanist Peter Raven puts it: "There is no science to back up the reasons for concern about foods from GM plants at all. Hundreds of millions of people have eaten GM foods, and no one has ever gotten sick."
Raven is quoted in a splendidly written book by the American environmentalist Stewart Brand (see last week's NS). Whole Earth Discipline nails the issue in just two chapters (the others are concerned with cities, geo-engineering and - importantly - nuclear power), but the book as a whole is this year's must-read for anyone who considers himself an open-minded green.
Admittedly, many activists I knew were never that convinced by the "Frankenfoods" argument: instead, their concern was that new, genetically engineered seeds would allow big corporations such as Monsanto to monopolise the world's food supply, to the detriment of poor countries. However, this should not be an argument to oppose the technology. It would more rationally suggest the need for an open-source approach, where the benefits of GM technology could be developed within, and for the benefit of, poorer countries (drought-tolerant, more nutritious and nitrogen-fixing subsistence crops are some examples under development).
What have I learned? Make sure your dearest principles can be reassessed in the light of changing evidence. We cannot criticise global warming sceptics for denying the scientific consensus on climate when we ignore the same consensus on both the safety and the beneficial uses of nuclear power and genetic engineering.