The controversy is global warming. Now, I'm a physicist, but I'm not the right kind of physicist. In regard to global warming, I'm just a layman.

And the rational thing for a layman to do is to take seriously the prevailing scientific theory. And according to that theory, it's already too late to avoid a disaster, because if it's true that our best option at the moment is to prevent CO2 emissions with something like the Kyoto Protocol, with its constraints on economic activity and its enormous cost of hundreds of billions of dollars or whatever it is, then that is already a disaster by any reasonable measure. And the actions that are advocated are not even purported to solve the problem, merely to postpone it by a little.

So it's already too late to avoid it, and it probably has been too late to avoid it ever since before anyone realized the danger. It was probably already too late in the 1970s when the best available scientific theory was telling us that industrial emissions were about to precipitate a new ice age in which billions would die. Now, the lesson of that seems clear to me, and I don't know why it isn't informing public debate.

It is that we can't always know. When we know of an impending disaster and how to solve it at a cost less than the cost of the disaster itself, then there's not going to be much argument, really. But no precautions and no precautionary principle can avoid problems that we do not yet foresee.

Hence, we need a stance of problem fixing, not just problem avoidance. It's true that an ounce of prevention equals a pound of cure, but that's only if we know what to prevent. If you've been punched on the nose, then the science of medicine does not consist of teaching you how to avoid punches.

If medical science stopped seeking cures and concentrated on prevention only, then it would achieve very little of either. The world is buzzing at the moment with plans to force reductions in gas emissions at all costs. It ought to be buzzing with plans to reduce the temperature and with plans to live at the higher temperature, and not at all costs, but efficiently and cheaply.

Some such plans exist, things like swarms of mirrors in space to deflect the sunlight away and encouraging aquatic organisms to eat more carbon dioxide. At the moment, these things are fringe research. They're not central to the human effort to face this problem or problems in general.

And with problems that we are not aware of yet, the ability to put right, not the sheer good luck of avoiding indefinitely, is our only hope, not just of solving problems, but of survival. So, take two stone tablets and carve on them, on one of them, carve, problems are soluble. And on the other one, carve, problems are inevitable.

@DavidDeutschOxf