Is making carbon 'SAFE' the answer?

30 November 2009

Mandating fossil fuel producers to sequester (bury) a steadily increasing fraction of the carbon they extract would be a simple, effective, and fair way of sharing out the pain of reducing greenhouse gas emissions, according to a leading group of climate researchers.
The concept, called SAFE (Sequestered Adequate Fraction of Extracted) carbon, is put forward by scientists from Oxford University and the University of Wyoming in a Commentary article published online today in a special issue of Nature Geoscience focusing on carbon sequestration.
The researchers suggest that fossil fuel producers could be mandated to sequester a steadily increasing fraction of the carbon they extract from the ground, with the fraction set to reach 100 per cent before total emissions into the atmosphere exceed an agreed total, with the costs passed on to fossil fuel consumers.
Their work explores the policy implications of research published earlier this year which showed that it is the total amount of carbon released into the atmosphere over all time that principally determines the risk of dangerous climate change, not the rate of emission in any given year.
'The neat thing about SAFE carbon is that is breaks the apparent conflict between short-term economic development and long-term climate protection,' said Dr Myles Allen of Oxford University's Department of Physics, an author of the paper with Dr David Frame, of Oxford University's Smith School of Enterprise and the Environment, and Chuck Mason, of the Department of Economics and Finance at the University of Wyoming.
Dr Allen added: 'We would no longer be asking a country like India to accept limits on their consumption. Instead, we would be saying that as long as you use SAFE carbon, you can go ahead and consume as much as you like. Of course, unlike a comprehensive emission permit or carbon tax regime, mandatory sequestration would not generate massive new government revenues or provide a mechanism for modifying consumer behaviour, but depending on your political perspective, that might be considered a good thing. We didn't save the Ozone Layer by rationing deodorant.'
 For more information contact Dr Myles Allen on 

Alternatively contact the University of Oxford Press Office on +44 (0)1865 283877 or email 

Notes to editors

  • The Commentary article, entitled 'The case for mandatory sequestration', is published online in Nature Geoscience today at:
  • A first study in Nature (April 2009), led by Dr Myles Allen from Oxford's Department of Physics showed that total cumulative emissions of one trillion tonnes of carbon (1 Tt C, or 3,670 billion tonnes of carbon dioxide­) over the entire 'anthropocene' period 1750-2500 causes a most likely peak warming of 2 degrees Celsius above pre-industrial temperatures. Most of the world's governments are committed to avoiding warming in excess of 2 degrees Celsius. 
  • A second study in Nature (April 2009), led by Dr Malte Meinshausen from the Potsdam Institute for Climate Impacts Research and co-authored by Dr Allen and Dr David Frame from the Oxford University Smith School of Enterprise and the Environment, found that a total emission budget of about 0.9 Tt C gives a best-estimate peak warming by 2100 of 2 degrees Celsius, including the effects of other human influences on climate. This budget drops to less than 0.75 Tt C (equivalent to 1,000 billion tonnes of carbon dioxide between 2000 and 2050) if the risk of temperatures exceeding 2 degrees Celsius is limited to one-in-four.
  • 'Save the trillionth tonne' research news release: