Climate Change......

is a fact, a human-made fact and a scary one.

The IPCC report was announced today. It's a vast report on the science of global warming written by the experts of the UN's Intergovernmental Panel on Climate Change (IPCC). The science report is the first of three major IPCC reports this year; similarly weighty analysis of the impact and possible solutions will follow in April and May respectively. The full triumvirate will then be given a final once-over in November, in time for key UN climate talks in Indonesia in December.

The report states that the weather is likely to warm by between 1.8 and 4 degrees c in the next 90 years and it could be as much as 10 degrees. It forecasts a rise of between 18cm and 58cm (half a metre!) in sea levels by the end of this century, a figure that could increase by as much as 20cm if the recent melting of polar ice sheets continues.

"This is just not something you can stop. We're just going to have to live with it," co-author Kevin Trenberth, the director of climate analysis for the US-based National Centre for Atmospheric Research, said in the Guardian today.

Another article in the Guardian last week which pre-empted the report said "Crucially, the report points out that a lag in the global climate system means that average temperatures would continue to rise by 0.1C a decade even if all sources of emissions were frozen today. And it says various positive feedback effects - such as forests, oceans and soil becoming less able to absorb carbon dioxide - could contribute another 1.2C of warming by the end of the century."

So no matter how much recycling and energy saving we do, the change is unstoppable - all we can do it to limit the scale of the change. The scale is very important. A 1 degree increase is frightening. a 3 degree increase means "In southern Europe, serious droughts occur once a decade. Between 1 billion and 4 billion people will suffer water shortages. Agricultural yields will be higher in mid-latitude countries such as Britain and the US, but there will be sharp drops in the tropics, putting 150-550 million people at risk of hunger. Between 1 million and 170 million more people will be affected by coastal flooding. One study suggests that between 20% and 50% of species will face extinction. On current trends, temperatures are predicted to rise 2C-3C by mid-century, which would result in 150-200 million climate refugees."

A 5C rise or above is called "Catastrophic impact - This is equivalent to the temperature rise since the last ice age. Most Himalayan glaciers will disappear, depriving 25% of China's population and hundreds of millions of Indians of water - melt water provides 70% of the water in the Ganges, for example. Sea level rise threatens cities such as London, New York and Tokyo. Rising ocean acidity will disrupt ecosystems and fish stocks. Feedback effects such as carbon dioxide release from soils and methane from permafrost kick in."

"This day marks the removal from the debate over whether human action has anything to do with climate change," Achim Steiner, the head of the UN environment programme, said - according to today's Guardian article.

This needs massive political commitment - it's useful to all do our bit, but we need to put our time and energy into calling for systematic change. December 2007 sees the UN climate talks in Indonesia. This will be the big chance for world governments to show that they understand the urgency of the problem.