I refer to the letters of Neil Craig and Chris Parton (December 4). First, I am not an eco-fascist, as Mr Craig has described me in his web comments. I have worked in the oil and gas sector for many years and consider that nuclear power is an essential ingredient in the future energy mix.

However, I do believe that any development has to be sustainable, which air and road travel using fossil fuels clearly aren't. The already high oil prices will continue to rise through increasing exploitation costs and an ever widening supply-demand gap. Higher costs will not only affect fuel but many essential products such as plastics and medicine.

Secondly, Mr Parton's allegation about the flat-earth brigade is the converse of what he suggests - it is, indeed, the case that those who hold traditional views about climate change being a natural cycle are the ones unwilling to accept the ever-increasing weight of evidence against them.

I agree there are questions on the reliability of historical temperature measurements but there is no doubt that the Earth is warming. Glacial retreat is a sustained and accelerating global trend, not just demonstrated by the 27 monitored by the World Glacier Monitoring Service but by many other observations around the world from scientists who have no desire to become embroiled in the global-warming debate. The Greenland ice cap, the Andes and Alaskan studies are typical examples, and all come to the same independent, alarming conclusion.

I mentioned two effects of glacial melt in a previous letter - a third consequence is the ever-expanding glacial lakes. More than 2000 of these exist in Nepal alone, held back by increasingly unstable natural dams. Many hundreds of thousands of people are at risk from their collapse. It is therefore preposterous and potentially disastrous to suggest that global warming is a political scam to keep the population alarmed.

Unlike Mr Craig, I do not question Sir David King's integrity with his assertion that there is an unarguable link between temperature rise and carbon dioxide levels. In fact, this difference of opinion now remains the only argument in favour of climate-change sceptics since all agree that atmospheric carbon dioxide levels are way above the normal range as far back as records go, and will continue to rise. We have had many natural cycles in the past but man's interference in nature has ended that. It's time the sceptics came on board and helped plan for our uncertain future.

Paul Shaw, 20 Argyle Way, Dunblane.

The now-well-documented historical records from ice cores from both the Antarctic and Greenland show some considerable rapid variations between climate in the past epochs and the most recent accelerating changes. For those in denial to try to refute this and other evidence from a small minority of glaciers is absurd. The massive overall loss of ice cover is now painfully obvious and recent Nasa reports show ever increasing losses from both major ice sheets.

The immediate danger to humanity is in the loss of sea ice which supports the glaciers fed by the major ice sheets, and their subsequent rapid collapse and break-up into the surrounding seas, triggering rapid massive sea level rises. We are also at risk of triggering tipping points in the burning of forests, melting of the permafrost and drainage of peat bogs and marshes, leading to further large releases of carbon dioxide and methane into the atmosphere.

Consideration of these increasing risks has led to the recent upward revision of the likely effects of global warming by the Intergovernmental Panel on Climate Change, which itself has often been criticised for being too conservative and understating the dangers to mankind. Rather than wasting time with this endless debate caused by a small minority of people in denial demanding "balanced coverage" by the media, we should be putting our efforts into developing mitigation and adaptation strategies.

Beyond the immediate dangers to transport links, telecoms and energy networks, military bases and emergency services are increasing threats to human and animal health, biodiversity and food supplies. Rather than looking forward to a balmy Mediteranean climate, we will face increasingly severe weather events and may even experience rapid cooling. This will make it difficult for farmers to predict which crops to plant against a back-ground of declining global supplies.

Mic Starbuck, 22 Cornwall Avenue, Burnside.