By Tim Rayner and Andrew Jordan

As the Conference of the Parties to the UN Framework Convention on Climate Change convenes for the 19th time in Warsaw, the likelihood that the world can fulfill the Convention’s ultimate objective of avoiding ‘dangerous climate change’ is looking ever slimmer. Since the mid-1990s, that objective has been widely interpreted as preventing a mean global temperature increase of more than two degrees Celsius. The increasing likelihood that the two degrees target will not be achieved was re-iterated by results of the Intergovernmental Panel on Climate Change’s (IPCC) science report published in September. It shows that the target implies a remaining global carbon budget equivalent to about one third of the greenhouse gases pumped into the atmosphere since industrialisation. At present rates, this budget could be used up entirely by 2040.

In a new Open Access paper in Climate Policy (Vol. 13, issue 6) written with colleagues from the Tyndall Centre, we argue that however uncomfortable a prospect, the time is now ripe to debate the future of the two degree target as the central aim of international climate policy. If the opportunity is not taken, by 2020 international climate policy could be premised on a target widely acknowledged to be unrealistic, leaving policy with even less credibility and society under-prepared to adapt to a significantly warmer world. Our paper begins to identify, for the first time, key uncertainties, risks and opportunities associated with four policy alternatives:

  • Adjust climate policy to an amended goal of ‘Mitigate for 2 but adapt for 4 degrees’, thereby ‘hedging our bets’ by taking steps to adapt to higher temperatures whilst stepping up to a higher level of mitigation effort.
  • Adopt new goals’: since the two degrees target appears unable to stimulate significant decarbonisation in the short-term, more specific and near-term targets should be adopted.
  • Be politically more pragmatic’: society should accept that science-informed targets such as two degrees have failed to drive change and instead concentrate on taking politically achievable steps in the short to medium term (without an explicit ‘target’ structure).
  • Re-commit to staying within 2 degrees’: the growing likelihood, recently confirmed by the IPCC, of high rates of warming makes it even more important to recommit to what it referred to as “substantial and sustained reductions” in GHG emissions, whatever the cost.

Significantly, therefore, one of the possible options is to acknowledge how radical the changes required to deliver two degrees would really be – potentially including restrictions on economic growth and exploring new definitions of prosperity – and to act meaningfully on this acknowledgment. However politically unpalatable this may be to western societies, could it be that given the choice, citizens might prefer this radical future to the kind of radical future associated with dangerous climate change?

Going beyond two degrees? The risks and opportunities of alternative options                     in Climate Policy Journal, Vol. 13, issue 6.

Tim Rayner and Andrew Jordan, Tyndall Centre for Climate Change Research,University of East Anglia.