Cabot Institute blog

Find out more about us at

Tuesday, 12 August 2014

Responding and adapting to climate change: Recognizing and managing uncertainty in the physical, social, and public spheres

A meeting of international experts at the University of Bristol addresses one of the crucial issues facing humanity. 

“Uncertainty, uncertainty, uncertainty … so why should we bother to act?”
Who hasn’t heard politicians or media personalities appeal to uncertainty to argue against climate mitigation? And indeed, why should we interfere with the global economy when there is uncertainty about the severity of climate change?

Some 20 leading experts from around the world will be meeting in Bristol late in September to discuss the implications of scientific uncertainty on the proper response to climate change.

This is particularly crucial because in contrast to the widespread public perception that uncertainty is an invitation to delay action on climate change, recent work suggests that scientific uncertainty actually provides an impetus to engage in mitigative action. Specifically, the greater the scientific uncertainty, the greater are the risks from climate change.

This conflict between people’s common perceptions of uncertainty and its actual implications is not altogether uncommon, and there are many situations in which people’s risk perception deviates from best scientific understanding.

The Bristol meeting brings together scientists and practitioners with the goal of (a) developing more effective means to communicate uncertainty and (b) to explore how decision making under uncertainty can be better informed by scientific constraints.

To address the scientific, cultural, health, and social issues arising from climate change requires an in-depth and cross-disciplinary analysis of the role of uncertainty in all of the three principal systems involved: The physical climate system, people’s cognitive system and how that construes and potentially distorts the effects of uncertainty, and the social systems underlying the political and public debates surrounding climate change.

The results of the meeting will become publicly available through scientific publication channels, with the details to be announced closer to the time of the meeting. In addition, two attendees at the meeting will be presenting public lectures at the University of Bristol:

Friday 19 September, 6:00-7:30 pm. Dogma vs. consensus: Letting the evidence speak on climate change.

In this Cabot Institute public lecture, we are pleased to present John Cook, Global Change Institute, University of Queensland, and owner of the Skeptical Science blog, in what promises to be a fascinating talk.

In 2013, John Cook led the Consensus Project, a crowd-sourced effort to complete the most comprehensive analysis of climate research ever conducted. They found that among relevant scientific articles that expressed a position on climate change, 97% endorsed the consensus that humans were causing global warming. When this research was published, it was tweeted by President Obama and received media coverage all over the world, with the paper being awarded the “best article” prize by the journal Environmental Research Letters in 2013. However, the paper has also been the subject of intense criticism by people who reject the scientific consensus. Hundreds of blog posts have criticised the results and newspapers such as the Wall Street Journal and Boston Globe have published negative op-eds. Organisations who deny or reject current science on human-caused climate change, such as the Global Warming Policy Foundation in the UK and the Heartland Institute in the US, have published critical reports, and the Republican Party organised congressional testimony against the consensus research on Capitol Hill. This sustained campaign is merely the latest episode in over 20 years of attacks on the scientific consensus on human-caused global warming. John Cook will discuss his research, both on the 97% consensus and on the cognitive psychology of consensus. He will also look at the broader issue of scientific consensus and why it generates such intense opposition.

Register for this free event.

Tuesday 23 September 2014, 6 pm to 7.30 pm. The Hockey Stick and the climate wars—the battle continues…

In this Cabot Institute lecture, in association with the Bristol Festival of Ideas, Professor Michael E Mann will discuss the science, politics, and ethical dimensions of global warming in the context of his own ongoing experiences as a figure in the centre of the debate over human-caused climate change.

Dr. Michael E Mann is Distinguished Professor of Meteorology at Penn State University, with joint appointments in the Department of Geosciences and the Earth and Environmental Systems Institute. He is also director of the Penn State Earth System Science Center. He is author of more than 160 peer-reviewed and edited publications, and has published books include Dire Predictions: Understanding Global Warming in 2008 and The Hockey Stick and the Climate Wars: Dispatches from the Front Lines in 2012. He is also a co-founder and avid contributor to the award-winning science website

Register for this free event.


This blog is by Cabot Institute member, Prof Stephan Lewandowsky of the School of Experimental Psychology, University of Bristol.  You can also view this blog on the Shaping Tomorrow's World blog.
Prof Stephan Lewandowsky

Friday, 1 August 2014

Prospects for Paris 2015: some thoughts on climate risk management with heterogeneous countries

Dr Simon Buckle, Policy Director at the
Grantham Institute
Dr. Simon Buckle, Policy Director of the Grantham Institute for Climate Change (Imperial College), presented at the Cabot Institute his view about credible and viable mitigation commitments in view of the COP 21 on Climate Change that will take place in Paris in 2015. Dr. Buckle’s presentation developed around a political question: do countries want the same climate? In particular, he explained that countries have different attitudes towards risks and this, coupled with the absence of a supranational legal authority, makes climate negotiations particularly complex. So far, such different priorities have caused the failure of UN international negotiations on climate, and countries have systematically missed their targets to limit their carbon emissions. In spite of this, media coverage and public engagement in this topic are sluggish and this undermines the effectiveness of climate policies. I think that the political nature of the issue should be highlighted and critically explored even when presenting climate and economic models, and that’s why Dr. Buckle’s presentation was particularly insightful.

Climate change and political judgment 

The last IPCC report concluded that it is
absolutely mandatory to reach an
agreement on mitigation.
The climate challenge represents a global issue whose effects in the long-term are potentially irreversible. Moreover, the last IPCC report concluded that it is absolutely mandatory to reach an agreement on mitigation; this means that countries will have to agree not only on emissions reduction targets but also on responsibilities and burden sharing. In 1992 the UN Framework Convention on Climate Change established the principle of “common but differentiated responsibilities”, but today it is still contested how responsibilities should be concretely allocated. In fact, the actions that emitters should take to tackle global warming raise fundamental political issues of intra-generational and inter-generational equity. They would require combined efforts to limit carbon emissions and reduce the use of fossil fuels, which represent an integral part of the economic growth and, therefore, are likely to affect the trajectory of a country’s development.

The potential responses can be based on mitigation (the transformation to a low-emission economy to reduce climate risks); adaptation (limit losses through increased resilience) or geo-engineering (for instance, solar radiation management or carbon capture and storage). In engaging with the question about the degree to which we should act on mitigation, economists prescribe different models that take into account, for instance, how economic growth is modelled, or how climate change affects output and growth, whether there are thresholds or other assumptions on ecosystem services. This highlights the political nature of the matter. In fact, the empirical evidence on impacts of climate variability and change and the effectiveness of adaptation is limited and while recent studies (Dell et al. 2012; Brown et al. 2013; Hallegatte et al. 2013) discuss the impacts on growth of climate change, there are not real analogues of large-scale climate change to inform economic models. This means that policies on climate change should be based on a political judgment about risk management, not exclusively on a technical cost-benefit analysis.

A credible negotiating strategy 

Dr. Buckle investigates the reasons that have so far lead to the failure of international negotiations on climate. In particular, he developed a stylised model that captures, directly and analytically, the trade off between consumption and the impact of climate damages on the long-term value of a bequest to future generations and how this depends on initial endowments (Buckle et al. 2014). The model relates to international negotiations as it defines a new metric, the desired mitigation efforts, to evaluate countries’ mitigation commitments and informs international actors about the best strategic negotiating aim.

Ideally, the parties involved in the UN negotiations on climate should aim at becoming resilient low-carbon economies, but they differ on many dimensions that might hamper the success of the negotiations. In the view of overcoming this conundrum, Dr. Buckle’s model suggests that a degree of convergence between the parties would deliver the best credible commitment to emissions reduction. In particular, using Game theory considerations, he showed that such convergence would secure a Cournot outcome “where each country determines its own level of mitigation effort taking that of the other country as given” (Buckle et al. 2014:4) and would avoid the risk of a Stackelberg outcome, whereby a small group of major emitters impose their preferred level of climate risk to the international community.

Figure 1 An illustrative emissions reduction game for two countries (in Buckle et al. 2014:4)

While it’s true that a Cournot agreement is sub-optimal and, as such, insufficient to deliver ambitious targets, it is absolutely pivotal that in Paris 2015 parties will sign a credible agreement for the short term. The theory is that if the parties managed to converge towards the Cournot agreement at the COP21, they will, eventually, move closer to a cooperative outcome in the longer term. In substantiating his argument, Dr. Buckle underlined the difficulties of reaching a cooperative outcome based on a global carbon budget. Moreover, he explained that the failures of previous negotiations stemmed from a too-ambitious commitment to move beyond “Business as Usual” that has so far fallen short of delivering the target of keeping global warming below the threshold of 2°C increase.

The Cournot outcome based on convergence, by contrast, would contain realistic targets decided by all the parties and not by few major emitters. Furthermore, the outcome will encourage not only cooperation but also R&D and innovation, which will benefit above all the most vulnerable countries. In concrete, Dr. Buckle argued that the best negotiating option would allow a global CO2 emissions peak by 2030 and a global but differentiated commitment to reduction, according to which developed countries would need to substantially reduce their emissions and at the same time promote financial and technological innovation; middle income countries would focus on reducing emissions intensity/GDP; and least developed countries would need to commit to a more modest reduction in the short term and develop a long-term low-carbon development path, avoiding the risk of carbon lock-in.

The future of climate negotiations? 

To conclude, it is mandatory that at the COP 21 the international community starts to engage proactively and positively in order to tackle climate change. Dr. Buckle’s view is that a gradual convergence and gradual move towards cooperative and environmentally effective agreements is preferable rather than facing another failure that we cannot afford.

Dr. Buckle’s conclusions will surely contribute to the debate on how we should achieve a substantial reduction of carbon emissions. From an environmentalist perspective, advocating for a gradual negotiating strategy that is “not enough” could be problematic. The last geopolitical turmoil, however, and particularly the worsening of the crisis in Ukraine, should make us aware that we cannot take the willingness to commit and cooperate of the international community for granted. Therefore, although the proposed solution might be far from optimal, it may just be strategically the most credible one.


Buckle S., Muûls M., Leib J. and Bréchet T. (2014), ‘Prospects for Paris 2015: do major emitters want the same climate?’, Core Discussion Paper – Centre for Operations Research and Econometrics, 2014
This blog is written by Cabot Institute Press Gang member Laura DeVito.  Laura is an Environment, Energy and Resilience PhD student at the University of Bristol.
Laura DeVito