The Minister for the Environment, Mr Dempsey, recently described climate change as "probably the greatest environmental threat facing the global community". Most scientists would agree; indeed, they would go further by saying it is the greatest threat to the survival of humanity on the planet.
Two years ago the UN's Intergovernmental Panel on Climate Change (IPCC), involving some 2,000 scientists from around the world, said: "The balance of evidence suggests that there is a discernible human influence on global climate". It called for action on the greenhouse-gas emissions which are to blame.
The IPCC's latest assessment report, published in December 1995, appeared to confirm the doom-laden view of environmentalists that global warming is already a fact of life, rather than a distant threat we can afford to ignore. Can it not be seen at work in the extreme weather events experienced in recent years? John Gummer, the former British environment secretary, declared in January 1996 that action needed to be taken "not tomorrow but now" to deal with it. What he was saying was that within the lifetime of today's children "the climate will change to a degree which will utterly alter the basis of their lives".
Global average temperatures are now rising faster than at any time since the last Ice Age, 10,000 years ago. The warmest year ever recorded was 1995, and the previous warmest 1990. In mid-latitude areas such as Europe and the US a rise of one degree Celsius is equivalent to moving 500 kilometres to the south.
No doubt there are many people who look forward to Ireland becoming a wine-producing country as a result of global warming. But this is surely a facile response to the threat of climate change, which could also result in losing some stretches of the coastline as sea levels rise over the next century or so.
One of the great imponderables is the extent to which the giant glaciers of Greenland and the Antarctic will break up as a result of rising global temperatures. Since most of the world's fresh water is trapped in these glaciers, the release of even a small proportion of their volume would add significantly to sea levels.
A rise of just 50 centimetres in such levels would inundate lowlying coastal areas in Bangladesh, Egypt and the coral reef islands of the Pacific, such as Fiji. Other idyllic holiday islands in the Indian Ocean, notably the Maldives, could be wiped off the world map by rising sea levels, compounded by tropical storms.
Ten per cent of the world's rice production in south-east Asia is also considered to be vulnerable, as Paul Brown points out in his book, Global Warming, Can Civilisation Survive? This would create 50 million "environmental refugees", more than three times the number from all causes in the 1990s.
In Egypt a one-metre rise in sea levels would result in the loss of at least 10 per cent of its productive land, with up to 10 million people losing their homes. "In a country which has a fast-growing population and a shortage of housing, this will make already difficult social problems more acute", Brown writes.
Even as it is, some 40 million people in the world are flooded every year as a result of storms, a figure expected to treble over the next century. And since it would be physically impossible to protect all these frontline areas, a "planned retreat" to higher ground may be the only long-term solution.
In Japan the cost of protecting all its ports against rising sea levels has been put at $92 billion. And although the work of raising the height of every harbour wall would be a great boon to its building industry, the bill would have to be met by society as a whole. Within the US the highest level of awareness about climate change is in Florida, and not without reason. Miami was built on a swamp, so even a sea-level rise of less than 20 inches would seriously threaten its survival. Multimillion-dollar beach homes in Malibu, near Los Angeles, also look increasingly vulnerable. "Of the 25 largest insured catastrophes in the US, 21 have occurred in the last decade, and 16 of the 25 involve a combination of wind and water", one leading American insurer noted in 1995. Even now, California is bracing itself for El Nino, a storm phenomenon caused by the warming of the Pacific. The flooding and flash floods which caused millions of pounds worth of damage on the Continent last summer may also be a foretaste of even greater natural disasters. And the cost of coping with such disasters is likely to become an even greater burden than taking steps to combat global warming. Droughts in Africa are also expected to become more frequent as a result of climate change, threatening starvation for millions. And as average global temperatures rise, even by just a few degrees, malaria could spread northwards from Africa as the mosquitos which carry the disease move into a warmer Europe.
More drought in sub-Saharan Africa and the Middle East means less water, and without water life is impossible. By 2025, it is estimated by the World Bank, 34 countries will suffer from serious water scarcity, raising the risk that future wars will be fought not about oil but about people's very survival.