The Two Degrees Dangerous Limit for Climate Change: Public Understanding and Decision Making

By adopting climate stabilization goals to limit temperature increases to a specified amount—usually two degrees Celsius (2°C)—above preindustrial levels, they demonstrate their commitment to solving a pressing global problem. Unfortunately, governments worldwide have delivered mainly promises so far, and their climate policies have been much more about intentions than about results. The policy relevance of climate science has been restricted mainly to policy formulation. It has not been translated into appropriate action.

That climate target-setting at the United Nations (UN) level has not been followed by radical cuts in global emissions is reason enough to criticize and reject the dominant “targets and timetables” approach, as shown by the work of scholars such as David Victor, Roger Pielke Jr., Steve Rayner, and Mike Hulme. In his insightful book. The Two Degrees Dangerous Limit for Climate Change: Public Understanding and Decision Making, Christopher Shaw takes a somewhat different perspective. Even though it clearly identifies the many shortcomings of the two degrees climate target, Shaw’s critique is primarily concerned with the democratic quality of the decision-making process and the particular level set for dangerous climate change. “If climate change is the greatest challenge facing humanity,” he asks, “what sort of democracy is it that does not give people a say in the trade-offs that responding to climate change requires?”

The two degrees target is the result of a cooperative and mutually beneficial relationship between climate science and policy. The target’s development began as early as the mid-1990s, in an attempt to operationalize Article 2 of the UN Framework Convention on Climate Change (UNFCCC), with an objective to “prevent dangerous anthropogenic interference with the climate system.” The two degrees target was formulated through a dialogue between climate scientists and scientific policy advisors and was formally adopted by policy makers at the 2010 UN climate change conference in Cancún (COP16).

For almost 20 years now, the two degrees target has worked as an “anchoring device.” It allows networks of diverse actors to communicate and interact, albeit with varying motivations and objectives. For climate policy makers, the target has served as a prominent symbol of an ambitious global mitigation effort. For climate scientists, it has provided the basis for complex calculations to determine carbon budgets and emissions reduction paths, which in turn are used to demonstrate the usefulness of scientific tools in the design and evaluation of climate policies. Through their interactions, scientists and policy makers provide each other with mutual reinforcement and recognition: the scientific community lends support and legitimacy to political efforts to advance the climate policy agenda, while policy makers support climate research, which in turn is reflected in heightened public awareness and significantly increased funding.

Shaw does not see this as evidence of success. From his perspective, which focuses on the interests of vulnerable countries and marginalized communities, the broad consensus on two degrees is problematic in several respects. First, the assumption that avoiding dangerous climate change means the same thing for the whole of humanity effectively masks conflicts between the interests of different countries and social groups. Second, the logic of risk management and safety limits not only frames climate change as a technical issue that can be managed by experts, but also establishes the idea of an “acceptable” amount of climate change or greenhouse gas emissions. Third, by setting the limit at a temperature level that might not be crossed for decades to come (since there is a time lag between emissions and temperature response), the two degrees storyline depicts climate change primarily as a problem that will become palpable only in the future. Fourth, since the two degrees limit is usually not presented to the public as co-produced by scientists, advisers, and policy makers, but rather as a hard scientific fact, it discourages public scrutiny of both the idea of a single global limit and of the particular level set. Last but not least, the two degrees limit represents an elite consensus from which marginalized and dissenting voices have been excluded.

The unique feature of the book, which is based on Shaw’s doctoral dissertation, is that it examines public representations of the two degrees limit in the United Kingdom. Analyzing news media and interviews conducted with climate scientists, policy makers, and activists, Shaw is able to reconstruct how the concept of a single, global measure of dangerous climate change became established within the climate debate in the United Kingdom, and how it has been legitimated and sustained within the British public sphere.

Although Shaw’s critical analysis of British media and policy discourses does not offer especially fresh insights, it is fascinating to read how scientists, policy makers, and activists deal with the underlying complexities of the two degrees limit.  Shaw sees a “not in front of the children” approach at work here. Policy wonks usually know quite well that there cannot be a single threshold to dangerous climate change. Some even know that two degrees is based on a set of uncertain assumptions, a rather contingent choice not very well founded in climate science. Yet in public, they all defend the established concept, since it is such a powerful instrument for climate policy formulation, or, as a campaigner puts it: “Uncertainty is really not a big help in the political domain and public communication.”

Shaw’s critical examination of the now-established concept of setting a limit for dangerous climate change comes at the right time—or maybe a bit too early. Unfortunately, the book does not reflect on the outcome of the Paris climate summit (COP21) in December 2015, which brought about a new target formula: the intention of “holding the increase in the global average temperature to well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change.” The UNFCCC even demanded that the Intergovernmental Panel on Climate Change (IPCC) write a special report on 1.5°C by 2018, although the new “pledge and review” approach that is at the heart of the Paris Agreement commits signatories to an aggregate emissions level in 2030 that would probably  lead to a 3° to 3.5°C temperature increase  by 2100.

So what might Shaw make of 1.5°C? Although not the consensus-anchoring device of two degrees, this lower target has been part of UN negotiations since the Copenhagen summit (COP15) in 2009. Shaw’s book mentions it occasionally, mainly to show that there have been alternatives to 2°C under discussion that aimed to lower the acceptable level of climate risk, particularly for the most vulnerable countries. But since a 1.5°C limit for dangerous climate change shares  many features with the two degrees  limit, Shaw’s approach contains a healthy  wariness toward a mere change of the  target’s level if the process of arriving at  that result remains unchanged. Or, as he  puts it: “The question is not just what,  if anything, should replace the idea of a two degrees limit, but who should decide  what, if anything, replaces it.”

The Two Degrees Dangerous Limit for Climate Change is a valuable contribution to the critical debate about global climate targets, which has entered a new phase after the Paris Agreement. We can hope that the 1.5°C decision, the commissioning of a new IPCC special report on 1.5°C, and the obvious inconsistency between talk, decisions, and action in UN climate policy making will motivate a more fundamental debate on the use and abuse of targets in climate policy.  So far, the setting of long-term global climate stabilization targets has not been a prerequisite but rather a substitute for appropriate action.

Oliver Geden (oliver.geden@swp-berlin. org) is head of the European Union Research Division at the German Institute for International and Security Affairs (SWP) in Berlin.