Brian Clegg - The Global Warming Survival Kit: The Must-Have Guide to Overcoming Extreme Weather, Power Cuts, Food Shortages and Other Climate Change Disasters

THE EARTH'S CLIMATE is changing. This is not news. The US National Academy of Sciences made their first study of global warming back in 1978. Although widespread acceptance that there is a serious problem took time to develop, the impact of climate change has now been studied for a good number of years and the vast majority of scientists accept that this change is strongly influenced by human activity.

The UN added its support in the 2007 report from the Intergovernmental Panel on Climate Change (IPCC), stating that global warming is unequivocal fact, and that most of the rise since 1950 is most likely (with a better than 90 per cent confidence) to have been caused by human intervention. 'February 2 [2007] will be remembered as the date when uncertainty was removed as to whether humans had anything to do with climate change on this planet. The evidence is on the table,' said Achim Steiner, executive director of the UN Environment Programme.

Even the few who don't accept a man-made component admit that we are undergoing global warming. According to the IPCC, the world can look forward to centuries of climbing temperatures, rising seas and disrupted weather. All the evidence is that the world is warmer now than at any time in the past two millennia; if current trends continue, by the end of the century it will be the hottest it has been in two million years.

The ten warmest years on record have all occurred since 1990, and most Of those were in the last decade.

There is a lot of talk about action to prevent climate change but, realistically, this is not likely to have enough effect. It is almost certainly a matter of too little, too late. Even if we persuaded the western world to give up its love affair with the SUV and cheap flights, the economies of China and India are gearing up to rival the US, currently the biggest influencer of climate change. It has been argued that the only way to prevent climate change from passing through a tipping point after which warming will accelerate beyond our control is to reduce greenhouse gas emissions by 90 per cent by 2030. No politicians are suggesting cuts that will achieve anywhere near this level of reduction.

We don't have to reach that tipping point to see climate change accelerating. Already the trends are getting worse. As New Scientist magazine said in February 2007, 'The [IPCC] authors acknowledge that they were being conservative. There is, though, a fine line between being conservative and being misleading, and on occasion this summary crosses the line. It omits some real risks either because we have not pinned down their full scale or because we do not yet know how likely they are.' Every week brings new revelations that global warming will hit us harder and sooner than was previously thought. John P. Holdren, president of the American Association for the Advancement of Science, wrote in 2007: 'Since 2001, there has been a torrent of new scientific evidence on the magnitude, human origins and growing impacts of the climatic changes that are under way. In overwhelming proportions, this evidence has been in the direction of showing faster change [and] more danger ...' The world is on the brink of disaster.

Apart from a relatively small impact from the heat of the Earth's core, the world's warmth comes from the Sun. Without the energy of sunlight, the surface of the Earth would be similar to that of one of the distant planets in the solar system with a temperature hovering below the 250C mark. The Sun's warmth is essential to preserve life but it is also the Sun that pushes us into global warming. Normally a fair amount of the Sun's energy is reflected back off the Earth out into space. The more of that energy that is absorbed rather than reflected, the more Earth temperatures will rise.