Page last updated at 10:54 GMT, Thursday, 10 December 2009

UK Met Office warns carbon emissions must peak by 2020

By Richard Black
Environment correspondent, BBC News website, Copenhagen

An aerial view of buildings standing out amid haze engulfing Wuhan, central China
The Met Office says global carbon emissions need to peak by 2020 to hit the G8's target

Keeping global temperature rise under 2C (3.7F) will be almost impossible unless carbon emissions begin to fall within a decade, analysis suggests.

The conclusion comes from a study by the UK Met Office (UKMO).

Even if emissions peaked in 2020, there would be a 50% chance of temperatures rising by more than 2C, the target adopted by the G8 at its July summit.

Meeting the lower target of 1.5C favoured by some developing countries is virtually impossible, the UKMO says.

If you go to 2025 before peaking, it's virtually impossible to stay under 2C
Vicky Pope, UK Met Office

The findings come from the Avoid programme, run by the Met Office in conjunction with other UK research institutions under government funding.

The latest results were presented at the UN climate summit in Copenhagen.

The Avoid programme aims to use the latest scientific understanding to make risk-based assessments of the impacts, global and regional, of rising greenhouse gas emissions.

'Virtually impossible'

Echoing the general conclusion of other analyses, including by the Intergovernmental Panel on Climate Change (IPCC), the Avoid researchers conclude that the earlier global emissions peak and begin to decline, then the gentler that decline can be.

CLIMATE CHANGE GLOSSARY

So peaking in 2018 and shrinking emissions by 4% per year after that would give a 50% chance of keeping warming below 2C, it calculates.

But if the peak came just two years later, in 2020, the decline would then have to be 5% per year for the same odds of staying below 2C.

"If you go to 2025 before peaking, it's virtually impossible to stay under 2C," said Vicky Pope, head of climate science at the Met Office.

Drawing on socio-economic research from other institutions in the project, the Avoid team believes that cutting emissions by more than 5% per year would be the maximum feasible.

'Negative emissions'

A bloc of small island states and vulnerable African countries are demanding that any new deal on climate change should aim to keep the temperature rise below 1.5C.

But the Met Office analysis suggests that would be very difficult.

"There's no way you'd get a 50% chance of avoiding 1.5C," Ms Pope told BBC News.

Graphic of global warming projection (Image: BBC)

"If you reduced everything to zero immediately you'd still get about 1.3C because of the greenhouse gases already in the atmosphere."

Policies to ensure a reasonable chance of remaining under 1.5C would involve "negative emissions" - sucking CO2 out of the air - she said.

And if emissions peak later than 2020, negative emissions - a form of geo-engineering - would be needed even to hit the G8's 2C target.

The concept of geo-engineering has its adherents but it is also fraught with economic, social and technical difficulties.

A report by the UK's Royal Society, released in September, concluded that although the approach might have a role, there were "major uncertainties regarding its effectiveness, costs and environmental impacts", and was no substitute for curbing emissions.

It was announced on Thursday that more than 1,700 scientists had signed a statement to defend climate science.

The response has been co-ordinated by the Met Office in the wake of the "ClimateGate" row.

The scientists became concerned after climate change "sceptics" claimed e-mails taken from servers at the University of East Anglia's Climatic Research Unit (CRU) suggested researchers had manipulated evidence.

Richard.Black-INTERNET@bbc.co.uk


Do you have a question for world leaders at Copenhagen? What would you ask them if you were at the summit? Send it to us. The best questions we receive will be answered by a panel of world leaders in a special televised debate.

Send your video questions to yourpics@bbc.co.uk, text them to 61124 or if you have a large video file you can upload here.

Read the terms and conditions

Name
Town & Country
Phone number (optional):
Comments

The BBC may edit your comments and not all emails will be published. Your comments may be published on any BBC media worldwide.




Print Sponsor


RELATED INTERNET LINKS
The BBC is not responsible for the content of external internet sites



FEATURES, VIEWS, ANALYSIS
Has China's housing bubble burst?
How the world's oldest clove tree defied an empire
Why Royal Ballet principal Sergei Polunin quit

BBC navigation

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.

Americas Africa Europe Middle East South Asia Asia Pacific