You should spend about 20 minutes on Questions 1-5, which are based on Passage 1 below.

GLOBAL WARMING

Day after day we hear about how anthropogenic development is causing global warming. According to an increasingly vocal minority, however, we should be asking ourselves how much of this is media hype and how much is based on real evidence. It seems, as so often is the case that it depends on which expert you listen to, or which statistics you study.

Yes, it is true that there is a mass of evidence to indicate that the world is getting warmer, with one of the world's leading weather predictors stating that air temperatures have shown an increase of just under half a degree Celsius since the beginning of the twentieth century. And while this may not sound like anything worth losing sleep over, the international press would have us believe that the consequences could be devastating. Other experts, however, are of the opinion that what we are seeing is just part of a natural upward and downward swing that has always been part of the cycle of global weather. An analysis of the views of major meteorologists in the United States showed that less than 20% of them believed that any change in temperature over the last hundred years was our own fault-the rest attributed it to natural cyclical changes.

There is, of course, no denying that we are still at a very early stage in understanding weather. The effects of such variables as rainfall, cloud formation, the seas and oceans, gases such as methane and ozone, or even solar energy are still not really understood, and therefore the predictions that we make using them cannot always be relied on. Dr. James Hansen, in 1988, was predicting that the likely effects of global warming would be a raising of world temperature which would have disastrous consequences for mankind: "a strong cause and effect relationship between the current climate and human alteration of the atmosphere". He has now gone on record as stating that using artificial models of climate as a way of predicting change is all but impossible. In fact, he now believes that, rather than getting hotter, our planet is getting greener as a result of the carbon dioxide increase, with the prospect of increasing vegetation in areas which in recent history have been frozen wastelands.

In fact, there is some evidence to suggest that as our computer-based weather models have become more sophisticated, the predicted rises in temperature have been cut back. In addition, if we look at the much reported rise in global temperature over the last century, a close analysis reveals that the lion's share of that increase, almost three quarters in total, occurred before man began to 'poison' his world with industrial processes and the accompanying greenhouse gas emissions in the second half of the twentieth century.

So should we pay any attention to those stories that scream out at us from billboards and television news headlines, claiming that man, with his inexhaustible dependence on oil-based machinery and ever more sophisticated forms of transport is creating a nightmare level of greenhouse gas emissions, poisoning his environment and ripping open the ozone layer? Doubters point to scientific evidence, which can prove that, of all the greenhouse gases, only two percent come from man-made sources, the rest resulting from natural emissions.

Who, then, to believe: the environmentalist exhorting us to leave the car at home, to buy re-usable products packaged in recycled paper and to plant trees in our back yard? Or the sceptics, including, of course, a lot of big businesses who have most to lose, when they tell us that we are making a mountain out of a molehill? And my own opinion? The jury's still out as far as I am concerned!