The scientists behind recent papers on carbon dioxide emissions and climate change have issued an open letter [see full text below] calling on the negotiators in the Bonn Climate Change Talks to acknowledge the need to limit cumulative emissions of carbon dioxide.
‘In addition to setting targets for emissions in 2020 and 2050, we feel the UNFCCC process should acknowledge that avoiding dangerous climate change will require emissions of the longest-lived greenhouse gases like carbon dioxide eventually to cease altogether,’ explains Dr Myles Allen of Oxford University’s Department of Physics.
Three of the letter’s signatories – Dr Myles Allen, Dr David Frame, of Oxford University’s Smith School of Enterprise and the Environment, and Dr Malte Meinshausen of the Potsdam Institute for Climate Impacts Research – will present the case for limits on cumulative carbon dioxide emissions at the Bonn talks on Thursday 11 June alongside David Hone, Group Climate Change Advisor for Shell, and Benito Mueller, Oxford Institute for Energy Studies.
For further information contact the University of Oxford Press Office on +44 (0)1865 283877 or email press.office@admin.ox.ac.u
Notes to editors
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Open Letter to the Negotiators of the UNFCCC:
The need to limit cumulative carbon dioxide emissions to avoid dangerous climate change
We welcome the efforts of governments around the world to reach agreement on measures to reduce greenhouse gas emissions, and wish to draw attention to recent scientific research indicating that a key determinant of the risk of dangerous climate change is cumulative emissions over all time of the longest-lived greenhouse gases, in particular carbon dioxide. This has three important implications:
First, current emission trends are incompatible with the goal of limiting cumulative emissions to a level that provides an acceptably low risk of dangerous climate change. Estimates of tolerable risk and allowable emissions vary, but in all cases costs rise sharply with the speed of emission reductions, so any affordable strategy to avoid releasing too much carbon dioxide in total will require global emissions to peak soon.
Second, in devising emission targets for 2020 and 2050, governments need to be aware of their implications for cumulative emissions. A policy that allows carbon dioxide emissions to rise over the coming decade in the hope of reducing them rapidly after 2020 results in a substantially higher contribution to the cumulative budget, and hence a greater contribution to the risk of dangerous climate change, than a policy of steady reductions reaching the same 2050 target.
Third, fossil carbon reserves substantially exceed the amount that can safely be released into the atmosphere. Net global carbon dioxide emissions will eventually have to decline towards zero leaving a substantial fraction of available fossil carbon stored, in some form, out of the atmosphere indefinitely.
We urge the participants in December's Conference of the Parties to the United Nations Framework Convention on Climate Change to acknowledge the need to limit cumulative carbon dioxide emissions as one element of their vision for long-term cooperative action to avoid dangerous climate change.
Myles Allen, Department of Physics, University of Oxford
David Archer, Department of Geophysical Sciences, University of Chicago
David Frame, Smith School of Enterprise and the Environment, University of Oxford
Damon Matthews, Department of Geography, Planning and Environment,
Concordia University
Malte Meinshausen, Potsdam Institute for Climate Impacts Research
Stephen Schneider, Department of Biology, Stanford University
Andrew Weaver, School of Earth and Ocean Sciences, Victoria University
Kirsten Zickfeld, Canadian Centre for Climate Modelling and Analysis
