Just Released: A Call For Cumulative CO2 Limit

Scientists call for limits on cumulative emissions
of carbon dioxide

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 United Nations Framework Convention on Climate Change [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,¹ explains Dr Myles Allen of Oxford University¹s Department of Physics.

Three of the letter¹s signatories ­ Dr Myles Allen, Dr David Frame, of Oxford University¹s 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 Dr Myles Allen on +44 (0)7776 306691 or Dr David Frame on +44 (0)7545 419909 or Professor Andrew Weaver +1 250 4724006

Alternatively, contact the University of Oxford Press Office on +44 (0)1865 283877 or email press.office@admin.ox.ac.uk

Notes to editors:

• The WIND/MoE meeting, ŒThe case for a cap on cumulative
  emissions of CO2 and other very-long-lived greenhouse gases¹, will be held
  in Bonn on 11 June 19:30-21:00. See:
  http://regserver.unfccc.int/seors/reports/events_list.html
  <http://regserver.unfccc.int/seors/reports/events_list.html>
• Bonn climate talks homepage:
  http://unfccc.int/meetings/sb30/items/4842.php
  <http://unfccc.int/meetings/sb30/items/4842.php>

——————————————————-

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