Time to debate the two degrees target

A new paper explores how policy makers can work with the uncomfortable knowledge that the prospects for holding average global warming to below two degrees Celsius are rapidly decreasing. They identify for the first time key uncertainties, risks and opportunities associated with alternatives to the two degree target of international climate policy, published in the peer-reviewed journal Climate Policy.

The likelihood that the two degree target will not be achieved was again suggested by the results of the Intergovernmental Panel on Climate Change’s (IPCC) science report published 27 September. It showed that the world’s ‘carbon budget’ - the amount of greenhouse gas that can be emitted without exceeding two degrees warming - could be used up entirely by 2040.  

 “Those concerned about climate change should now take the seemingly uncomfortable step of exploring the risks and opportunities associated with alternative goals and targets” says Professor Andrew Jordan of the Tyndall Centre for Climate Change Research and Professor of Environmental Politics at the University of Anglia.

Since the mid-1990s, the aim of international climate policy has been to keep the rise in global average surface temperature below two degrees Celsius. Previous warnings that humanity will overshoot this target have failed to stimulate climate policy.

The authors argue that given where emissions are in 2013, now is precisely the time to analyse more fully some alternative options. They identify for the first time key uncertainties, risks and opportunities associated with four policy alternatives that have been raised in the scientific literature:

•    Adapt climate policy to an amended goal of ‘Mitigate for 2 but adapt for 4’, thereby ‘hedging our bets’ by taking steps to adapt to higher temperatures whilst stepping up to a higher level of ambition regarding mitigation.
•    ‘Adopt new goals’: since the two degrees target appears unable to stimulate significant decarbonisation in the short-term, more specific 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 social change and instead concentrate on taking politically achievable steps in the short term without an explicit and overarching ‘target’.
•    ‘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 achieving what it referred to as “substantial and sustained reductions” in emissions.

At present, policy makers are stuck in a binary debate about whether or not the target of two degrees should or will be met. If the two degree target is downplayed and/or higher temperature limits are debated, breaching the two degree ceiling could easily become a self-fulfilling prophecy. On the other hand, failing to debate it could mean that by 2020, international policy is premised on an unrealistic target, further undermining its credibility.

“This need not be a pretext for abandoning the existing target. On the contrary, openly exploring the alternatives could encourage some of the policy makers who are less certain to commit more fully to the existing two degrees target, whatever it requires, as the least unattractive course of action” says Professor Jordan of the Tyndall Centre for Climate Change Research at the University of East Anglia.

In line with the climate challenges laid out in the recent IPCC report, all the alternatives discussed in the paper recognise the need for rapid and urgent policy responses. Sticking with the status quo – a target that will be exceeded relatively soon – is at risk of leaving society under-prepared for the challenge of adapting to a significantly warmer world.

The authors suggest that short-term policy making could be better informed by a more transparent discussion of what probability to aim for to avoid a 2°C temperature rise.

“Choosing either a high or a low chance of avoiding 2°C makes a significant difference to decision making around the feasibility of mitigation options, as well as the design of long lasting infrastructure intended to be resilient to future climate change impacts”, said Dr Alice Bows-Larkin, Reader in Energy and Climate Change at the Tyndall Centre for Climate Change Research at the University of Manchester.

The UN is currently (2013-5) reviewing the goal of international climate policy. Says co-author Professor Corinne Le Quéré, Director of the Tyndall Centre for Climate Change Research, “when
confronted with a deep policy dilemma, decision makers should be as aware as possible of all the implications of pursuing alternative courses of action”.
 
The paper is open access at Climate Policy http://www.tandfonline.com/doi/abs/10.1080/14693062.2013.835705#.Uk00piSsh8E

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