Climate evidence - what we must do29 April 2010
Why rich countries should make deep cuts in greenhouse gases. And why their emissions should peak no later than 2015.
Most governments agree we shouldn't allow global average temperatures to rise above 2 degrees Celsius on pre-industrial levels. Any higher and we risk runaway climate change.
Many say this means limiting greenhouse gases in the atmosphere to 450 parts per million carbon dioxide equivalent (ppmv CO2e).
But because we've already pumped out lots of CO2, by mid-century global emissions must fall by at least 80% compared with 1990 levels.
We can't wait til 2049 and do it all overnight. By then there will be so much carbon pollution that reversing global warming could be impossible.
When do we start?
Researchers at the UK's Tyndall Centre for Climate Change Research have looked at long-term trends and recent emissions.
They conclude:
If [global] emissions peak in 2015, stabilisation at 450 ppmv CO2e requires subsequent annual reductions of 4% in CO2e and 6.5% in energy and process emissions. [i]
They say that for rich countries the reductions would need to be greater.
The case for deep cuts is supported by a wealth of data. Here's a useful summary.
You can help us get on with making change at local level.
> What the UK should do - the evidence
[i] Anderson, K and A Bows, 2008. Reframing the climate change challenge in light of post-2000 emission trends. Philosophical Transactions, vol 366, p3863-3882
