Facts you should know about global warming - Part 1

Fact 1

In 1996, the Intergovernmental Panel on Climate Change (IPCC), representing 2,500 scientists, released a major assessment on climate change. The 3600-page report reduces many of the uncertainties surrounding the issue. Scientists are now more confident than ever that the emission of greenhouse gases through human activities is contributing to global warming. This will lead to climate change next century, with potentially disastrous impacts on biodiversity, coasts, agriculture, water and health.

Fact 2

The greenhouse effect is a natural phenomenon – if it weren’t for the natural greenhouse effect the Earth would be some 33°C cooler than it is at present. The planet is warm enough for complex life because naturally occurring gases (including carbon dioxide and water vapour) trap heat which would otherwise escape into space. The problem is that human activity – including combustion of fossil fuels and land clearing – is adding to these gases faster than oceans, plants and soil can absorb them. This is unnaturally ‘enhancing’ the greenhouse effect. Since the industrial revolution, the concentration of carbon dioxide, the main greenhouse gas, has increased by 30 per cent. Long-substantiated laws of physics tell us that, given we are altering the energy balance of the atmosphere, this will impact on the world’s temperature and climate.

Fact 3

The measured increase in temperature of about 0.3-0.6°C this century is consistent with the latest climate model predictions. The 1980s was the warmest decade on record, with 1990, 1991 and 1995 the three warmest years on record. This is not to say that the warming trend is the consequence of the enhanced greenhouse effect. However, recent studies show that the warming trend this century is unlikely to be due to natural phenomena such as increased solar output. The IPCC has now stated that ‘the balance of evidence suggests that there is discernible human influence on global climate’.