Passage Two Questions 56 to 60 are based on the following passage. Day after day we hear about how anthropogenic ( 人为的 ) development is causing global warming. According to an increasingly vocal minority, however, we should be asking ourselves how much of this media hype ( 大肆宣传 ) is based on real evidence. It seems, as so often is the case, that it depends on which experts 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 ysis of the views of major meteorologists( 气象学家 ) 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 change. 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 rising 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 wasteland.