Global warming – the facts

It is clear that human-induced global warming is already occurring. In its recent Fourth Assessment, the Intergovernmental Panel on Climate Change (IPCC) concluded that:

"Warming of the climate system is unequivocal... most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations’"

This statement comes from careful consideration of the evidence (including the influence of other natural factors on climate) by a large number of world-leading experts.

Global temperatures will continue to rise over the next few decades, and will probably reach over 1°C above pre-industrial levels even if we could fix greenhouse gas (GHG)HG concentrations at current levels.

But if they continue to grow along a ‘business as usual’ path, climate models suggest a possible warming up to nearly 7°C by 2100.

At the heart of the CCC’s advice is the use of robust and up-to-date scientific evidence. The Committee includes eminent scientists such as Lord Robert May, Professor Sir Brian Hoskins, and Professor Martin Parry. The CCC also works closely with many of the UK’s leading research centres.

But isn’t the science controversial?

The reality of climate change is not asserted by the IPCC alone. Key scientific institutions such as the Royal Society, the US National Academies and the World Meteorological Organization all agree that climate change is occurring, and that it poses risks to humanity unless action is taken.

Some aspects of climate change are subject to debate in the science community. For instance, while there is high confidence that global temperatures will increase in the future, there is less certainty about what will happen to rainfall in some places.

Other popular controversies are often based on faulty reasoning. Arguments that global warming has stopped in the last decade, or that the Sun is entirely to blame, are not supported by leading experts.

A helpful guide to some of these issues is available from the Met Office. Also, the New Scientist  has compiled easy-to-read responses for a range of common objections.