Ten years left to avert catastrophe
For the past six years, more than 2,000 scientists from around the world have been writing the most definitive and up-to-date assessment of climate change. It is the fourth report of the Intergovernmental Panel on Climate Change (IPCC) since it was set up by the United Nations and the World Meteorological Organisation in 1988.
The first volume of this assessment - called Climate Change 2007: The Physical Science Basis - will be published today at a meeting in Paris. It will be followed later in the year by two more volumes concerned with what we can expect this century in terms of climate change effects, and what we can do to minimise the impact that those effects will have on our way of life.
It is clear from the draft version of the IPCC's fourth assessment report on the science of climate change there is little doubt that global warming is a reality, and increases in the man-made emissions of carbon dioxide over the past 250 years are largely responsible.
There are still many uncertainties surrounding the issue of climate change, but these uncertainties should not be allowed to cloud the facts. The first is that levels of carbon dioxide in the atmosphere and increases in average global temperatures are higher than at any time over the past 650,000 years - and we know one can exacerbate the other.
It is also virtually certain that the burning of fossil fuels such as coal is responsible for the observed rise in carbon dioxide, the most important greenhouse gas in terms of global warming.
The IPCC has therefore concluded that the global warming we have observed in recent decades is the likely result of human activity.
The IPCC will point out that 11 of the 12 warmest years since 1850 have occurred since 1995. It expects global temperatures to rise by a further 3C by 2100.
Today's report is also expected to warn that sea levels will continue to rise this century, and the century after that, whatever we do to curb carbon dioxide levels. This is because of the inherent inertia of the climate system - the oceans contain about 1,000 times more heat than the atmosphere and so they respond more slowly to changes in global temperature.
If we want to avoid catastrophic increases in sea levels we must attempt to limit the melting of the giant ice sheets off Greenland and west Antarctica.
If one or both of the ice sheets disintegrate, sea levels would rise disastrously to inundate most of the major cities of the world as well as low-lying and densely populated countries such as Bangladesh.
Many scientists believe that we have about 10 years left to enact policies that will curb dangerous climate change.
Cow 'emissions' more damaging to planet than CO2 from cars
Greenham Reach: The families trying to prove that compact, ecological farms can make a living
Brazilian wandering spider: Where are they from and how deadly are they?
The ugliest animals on earth: Blobfish, axolotl and proboscis monkey battle it out to be named least attractive beast
A spotter's guide to a wild orchid summer
- 1 Engineer pictured fixing plane's engine with 'duct tape' by concerned EasyJet passenger
- 2 Two-year-old says goodbye to bin man best friend
- 3 Saudi Arabia mosque bombing: Two volunteer security guards hailed as heroes for stopping Isis suicide bomber reaching worshippers
- 4 There is something wrong but very right about this Bible illustration
- 5 Remove smartphones from the hands of under-18s and maybe they will grow up to be less dumb
EU referendum: David Cameron's rules are a 'democratic disgrace', says French-born Scottish politician set to be denied a vote
Migrants in Kos: Photos show real tragedy after Brits abroad complain of 'awkward' holidays
British tourists complain that impoverished boat migrants are making holidays 'awkward' in Kos
A nation of inequality: How the UK is failing to feed its most vulnerable people
Australian man punched in the face for defending Muslim women from abuse on train
EU referendum: David Cameron to deny EU migrants and under-18s the chance to vote
£14000 - £18000 per annum: Recruitment Genius: This is an opportunity for the ...
£14000 - £17000 per annum: Recruitment Genius: Full time Administrator/Secreta...
£16500 - £18500 per annum: Recruitment Genius: One of the leading Mercedes-Ben...
£27500 - £35000 per annum: Recruitment Genius: This is an exciting opportunity...