Plausible hypotheses are not scientific facts

Traditional sceptics on global warming are becoming believers. Al Gore\’s film \”An Inconvenient Truth\” has convinced many waverers. The Stern report in Britain has just called for urgent action to check global warming.

So, the current UN conference on climate change is putting unprecedented pressure on the US to join the Kyoto Protocol on reducing greenhouse gas emissions. Developing countries like India and China, which earlier refused to cap emissions on the ground that they were just starting up the development path, are under pressure to accept commitments too.

I have always been a qualified sceptic. Global warming is a plausible hypothesis. But it is not a proved scientific fact, as claimed by greens. The history of science is replete with plausible hypothesis that proved to be wrong.

Yes, the globe has warmed up in the last 30 years. But the world cooled down in the preceding 30 years (1945-75). Newsweek ran a cover story in 1975 declaring that the next ice age was coming. There can be no more salient warning of how dangerous it is to project 30-year trends forward for another 100 years.

Climatologists today declare that there will be droughts and agricultural calamities if the world warms up. Funnily enough, exactly the same warnings were issued in the 1970s about global cooling. Can it really be true that we will have an agricultural disaster whether the world cools or warms up? Or are worst-case scenarios parading as immutable truths?

We are told that the majority of climate scientists are of the opinion that global warming will reach catastrophic proportions by 2100. But science is not, and never has been, about collecting the opinion of scientists. That would be an opinion poll, not science.

Scientific method is very clear about the procedure to move from hypothesis to theory or fact. An experiment has to be devised which will conclusively prove or disprove the hypothesis. Only after passing such a test can a hypothesis rise to the status of a theory. And if the theory remains intact against rival theories for long enough, it will become a scientific law (like Newton\’s Laws of Motion).

However, this standard scientific methodology is not being followed in the case of global warming. Sundry computer projections on warming are being publicised by climatologists as scientific facts. Layfolk may think that computer modelling is high-tech proof. In fact computer modelling is rubbish-in and rubbish-out: by changing a model\’s specifications you can produce almost any result you want.

Wassily Leontief, who won the Nobel Prize for statistical modelling, gave an immortal description of the process. \”We move from more or less plausible but really arbitrary assumptions, to elegantly demonstrated but irrelevant conclusions.\”

Neither Al Gore nor any green wants to follow standard scientific method to move from hypothesis to proof. Why? Because if we tested various global warming models for a century to see whether they worked, the predicted disaster would already have happened, or not happened.

So, many experts want us to take a decision without concrete proof. If we wait decades for conclusive proof, they say, it may be too late to take preventive action.

This is altogether a more respectable argument than the claim that global warming is a scientific fact. There is a case for viewing emission curbs as an insurance premium worth paying just in case the disaster hypothesis, though unproven, is correct. Rational people buy insurance against events that may never happen. Homeowners in Delhi buy earthquake insurance, although no major earthquake may ever hit the city.

Is the Kyoto insurance premium commensurate with the insurance benefits promised? Only if it is small (as in the Delhi earthquake example).

Experts now estimate that checking emissions to safe levels will cost around 1% of GDP. That may not sound excessive. However, it translates into a whopping $ 500 billion a year at today\’s global GDP level. I would strongly oppose India paying anything like 1 % of its GDP as a premium, given the many uncertainties about global warming.

The US refuses to join Kyoto, saying it have to pay an unacceptably high premium. It also insists that it will not join until India and China, whose emissions are small but rising fast, make some commitments.

What position should India take? Traditionally, it has argued that its emissions are very low on a per capita basis, and so it should be exempted from Kyoto. The argument is a good one. Yet if the Goldman Sachs BRIC report is right in projecting India as having the third largest economy in the world by 2050, India can hardly insist that all premiums should be paid by today\’s OECD economies, almost all of which will be smaller than India\’s by 2050.

India-maybe in conjunction with other developing countries-could offer some limited commitments. These countries cannot be asked to cut their emissions to 5% below 1990 levels, the Kyoto target for rich countries. But India could offer to cap its greenhouse gas emissions at say the 1960 or 1970 per capita level of France or Germany. That level will not be reached for a long time, and may not be reached at all if new energy sources like solar electricity become viable. Yet it will be a reasonable commitment.

The main aim of such a strategy will be to persuade the USA to join Kyoto. By committing itself to pay a small premium many years hence, India may get the US to pay a large premium immediately. That will not quite be a free ride, but it will be a very low-cost one.

What if the US refuses to join anyway? In that case India should refuse too. Without US participation, no serious emission control is possible. The benefits of the insurance policy will not be commensurate with the premium.

Will such non-action be grossly irresponsible? No. Disaster is by no means certain. One scientist predicts that by 2100, science may enable us to control the world\’s temperature. That, too, is a plausible hypothesis.


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