There are several uncertainties in the climate system — incomplete knowledge about physical processes, multiple ‘scenarios’ that could be realised depending on human choices and actions, and ‘internal variability’ in the climate system, which makes perfect predictions impossible. These uncertainties make the process of climate policymaking — which is already difficult in a complex international political arena with multiple actors with diverging agendas and a lack of effective implementation mechanisms — even more difficult. Since much of the discourse around climate change and policy hinges on climate targets, I am interested in exploring the linkage between uncertainty and climate targets, particularly how the two interact and affect one another.
When the UNFCCC was founded in 1994, it acknowledged that though there are many uncertainties surrounding climate change, the “lack of full scientific certainty should not be used as a reason for postponing … precautionary measures to anticipate, prevent or minimize the causes of climate change and mitigate its adverse effects.” (UNFCCC 1992) This reflects its adoption of the so-called precautionary principle (Farber 2015), which remains the predominant frame of reference for climate policy, and which has guided many of the international agreements and treaties since then. Under the precautionary principle, a cost-effectiveness analysis (CEA) approach is used to determine the most cost-effective path to achieving a given goal (Farber 2015). The goal is determined by considering the available scientific knowledge and making a subjective decision about a limit beyond which the risks or impacts would be too great to endure. In the case of climate change, a 2-degree Celsius temperature increase was chosen as the target at Cancun in 2010, as there was sufficient evidence pointing to rapidly increasing risks beyond that. In this way, the precautionary principle allows the challenge of uncertainty to be somewhat sidestepped in the setting of climate targets.
Another link between uncertainty and climate targets relates to the evolution of these targets over time. While no quantitative temperature or concentration targets or clear timeframes were set when the UNFCCC was founded, over the years more precise targets such as the 2-degree target and emissions reductions schedules were developed. This development may be attributed, amongst other things, to a reduction in epistemic uncertainty about the climate: our understanding of the climate system, particularly in terms of its future response to anthropogenic emissions and the impacts of climate change, has improved in the past few decades, allowing for these more specific targets to be adopted.
When it comes to the evolution of climate targets, the ‘shifting baselines syndrome’ (SBS), which describes the gradual change in the accepted normal state of an ecosystem (Papworth et al. 2009), may also be relevant. Consider this example: people born in 2100 will be more accustomed to a warmer climate — perhaps already beyond the 2-degree target we have now — and their perception of what a ‘normal’ climate is will have shifted too. As a result, a new climate target, say 3 degrees of warming by 2150, would probably be formulated, which to us in the present would be undesirable and intolerable. This crude example highlights how SBS may play a role in the development of climate targets in the future, particularly from the point of view of individual and societal perceptions of targets. Though we are focussing on uncertainty, several other important factors also influence the creation and dynamics of climate targets, including international and domestic politics and technological advancements.
The influence of uncertainty on climate targets is relatively clear; however, whether there is an influence in the reverse direction is unclear. Though climate targets do not influence components of uncertainty in the climate system that are climate model-dependent or those that arise from a lack of scientific knowledge, they can impact peoples’ perception of climate change and the surrounding uncertainty. I think that the current form of climate targets, such as the 2-degree target, are effective in positioning climate change as a global issue that affects everybody and that we all must collectively address; however, at the same time, unidimensional targets such as these fail to capture more subtle aspects of the climate discussion, such as questions of climate justice, and make the problem seem deceptively uncertainty-free and simple. Such targets can also lead to confusion at an individual or collective level about what action is necessary or sufficient to meet the target, since targets are set at national or international, rather than local or individual levels. I think research into peoples’ perception of climate targets and associated uncertainties, as well as how this impacts action, is important as climate change becomes more urgent.
References
Farber, Daniel A. “Coping with uncertainty: Cost-benefit analysis, the precautionary principle, and climate change.” Wash. L. Rev. 90 (2015): 1659.
UNFCCC. United Nations Framework Convention on Climate Change: United Nations, FCCC/INFORMAL/84 GE.05-62220 (E) 200705. Bonn: Secretariat of the United Nations Framework Convention on Climate Change, 1992 unfccc.int/resource/docs/convkp/conveng.pdf.
Schmidt, Matthias GW, Alexander Lorenz, Hermann Held, and Elmar Kriegler. “Climate targets under uncertainty: challenges and remedies.” Climatic change 104, no. 3 (2011): 783-791.
“Timeline: UN Climate Talks.” Council on Foreign Relations. Council on Foreign Relations. Accessed August 14, 2022. https://www.cfr.org/timeline/un-climate-talks.
Papworth, Sarah K., Janna Rist, Lauren Coad, and Eleanor J. Milner‐Gulland. “Evidence for shifting baseline syndrome in conservation.” Conservation letters 2, no. 2 (2009): 93-100.
Feature image source: https://pxhere.com/en/photo/676337
Interesting point about the “2 degree target” simplifying the climate change debate. Even if we achieve the 2 degree target, we have not even begun to address climate change adaptation and the global logistics of preparing for a world of increasing extreme events.
It would be interesting to know more about the reasoning behind the adoption of 2 degree target at Cancun beyond it being the hottest global mean temperature humankind as a species has lived through. I’m sure there must be some social aspects such as the allowance of further fossil fuel consumption that overweighs the climate change impacts of the 2 degree target and specifically who it affects the most. The 2 degree target is already short end of the stick for low lying island communities and other highly vulnerable communities but we as a community have moved beyond trying to limit emissions as much as possible and preserving our climate to an arbitrary goal of 2 degrees.