Europe's long-term climate target: A critical evaluation (original) (raw)

Elsevier

Energy Policy

Abstract

The European Commission as a whole and a number of its Member States individually have adopted a stringent long-term target for climate policy, namely that the global mean temperature should not rise more than 2

°C above pre-industrial times. This target is supported by rather thin arguments, based on inadequate methods, sloppy reasoning, and selective citation from a very narrow set of studies. In the scientific literature on “dangerous interference with the climate system”, most studies discuss either methodological issues, or carefully lay out the arguments for or against a particular target. These studies do not make specific recommendations, with the exception of cost-benefit analyses, which unanimously argue for less stringent policy targets. However, there are also a few “scientific” studies that recommend a target without supporting argumentation. Overall, the 2

°C target of the EU seems unfounded.

Introduction

The European Union as a whole and some of its Member States individually have proposed a long-term target for international climate policy, which is that the world should not warm more than 2

°C above pre-industrial temperatures.1 This is an ambitious target. Given the current uncertainties, it would imply that the atmospheric concentration of carbon dioxide could not rise much above 400

ppm (Meinshausen, 2005), only some 20

ppm above today's concentration; if recent trends continue, the 400

ppm level would be reached by 2020 (after Keeling and Whorf, 2005). This paper reviews the reasons for adopting this target.

Previously, another target was circulated, namely that the rate of warming should not exceed 0.1

°C per decade. Although this target was frequently mentioned (e.g., Swart et al., 1989; Swart and Hootsmans, 1991), the main defence was always a reference to a previous paper. The 0.1

°C/decade target can be traced to the late 1980s, but then the trace vanishes. Apocryphal evidence2 holds that the 0.1

°C/decade target is appropriate for a plant species on the shores of a lake in North America. This study was never published, but mentioned at dinner during an early climate conference. Someone else repeated the information the next day in plenary, and an urban legend was born. As the 0.1

°C/decade target has vanished from policy discussions—perhaps because natural variability is greater3—it need not concern us any further. However, it is important to know whether the 2

°C is valid or similarly based on bogus science.

The 2

°C target is already almost 10 years old.4 It was first raised in WBGU (1995), and adopted in CEU—Council of the European Union (1996). It was little prominent for a while, but recently it has surfaced again (e.g., CEU—Council of the European Union, 2004) as the preparations for climate policy in the period after 2012 (the end of the first commitment period under the Kyoto Protocol) are starting. As the EU is one of the main players in international climate policy, its long-term target requires serious discussion.

The paper is structured as follows: Section 2 reviews the official documents that present the 2

°C target. The focus is on the European Union, Germany, the Netherlands and the United Kingdom. These three countries are at the forefront of European climate policy, and the author happens to be able to read their languages. Section 3 reviews the scientific literature that may substantiate, perhaps even justify a 2

°C target. Section 4 concludes.

This paper focuses on a particular target. Oppenheimer and Petsonk (2005) study the origin and varying interpretations of long-term targets for climate policy. Note that this paper does not suggest an alternative target for international climate policy. Although it does criticize the choice of target by the European Union, the main criticism is directed at the procedure by which this standard was set.

Section snippets

A review of official documents

CEC (2005a) repeats the earlier EU position that it “believes that global average temperatures should not exceed 2

°C above pre-industrial level”. The aim of CEC (2005a) is to conduct “a cost benefit analysis which takes account both of environmental and competitiveness considerations” [emphasis added].5

A review of the scientific literature

Campbell-Lendrum et al. (2003) is often quoted on the impacts of climate change on human health. This study does not recommend any temperature target. Instead, it compares impacts for unmitigated climate change, stabilisation at 750 and 550

ppm. Unfortunately, it does this comparison at 2030 only, at which time the three scenarios are hardly distinguishable. The stabilisation scenarios are the so-called “S” scenarios, which are unnecessarily expensive (Wigley et al., 1996), but Campbell-Lendrum

Discussion and conclusion

I reviewed Europe's 2

°C target for international climate policy in the long run. One may of course dismiss this target. Why does Europe decide on a global target? Are the days of colonialism not long past? It is of course perfectly legitimate for the EU to propose a global target. One may also dismiss Europe's target as just another grand plan, bound to suffer the same fate as the Stability and Growth Pact and the Lisbon Agenda, to name two recent grand plans by European governments that were

Acknowledgements

Sari Kovats and an anonymous referee provided helpful comments. The Michael Otto Foundation for Environmental Protection, the Hamburg University Innovation Fund and the Princeton Environmental Institute financially supported this research. All errors and opinions are mine.

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