For more than two decades, the world's governments have been engaged in international diplomacy to manage global warming. Those efforts, so far, haven't achieved much in part because most governments have not been willing to devote much effort to the task. Among the few notable exceptions are members of the European Union (EU). The EU was a relative latecomer to the mission of global warming, but since the 1990s, it has emerged as a reliable leader. Today, many in Europe think that global warming is one of the defining regulatory activities of the EU.

EU policies are consistently among the most aggressive efforts worldwide to control the emissions that cause global climate change. The EU is also in the lead in preparing to adapt to likely climate changes at home and helping other countries brace for the huge changes that will arise in a warmer world. The EU has translated this leadership in its own efforts into a big influence on the design of international institutions. For better or worse, many of the key elements of prominent international agreements in this area—such as the Kyoto Protocol and the Copenhagen Accord—reflect EU ideas.

This new book edited by Jordan et al. offers a careful assessment of how the EU makes policy related to climate change. It is part of a large EU-funded project that focuses on the design, politics, and effectiveness of EU strategies to adapt to climate change and regulate (“mitigate”) warming emissions. Written for specialists, it covers a broad landscape and is well informed.

The Jordan et al. book introduces many arguments, but four stand out as particularly important. First, EU policymakers have faced a wide array of challenges in the policymaking process. Those challenges—what Jordan et al. call “dilemmas”—included the need to set the agenda and choose policy instruments that would keep political forces supportive of regulation. One challenge stands out in this volume: sharing the burden of costly regulation. The chapters in this book show that the EU's credibility on climate change has risen as its member governments and bureaucrats have discovered ways to share burdens so that climate policy was politically tolerable within the EU. A few EU countries—mainly in the northwest—care a lot about climate change. The rest don't. The EU's burden sharing reflects that. As the EU has expanded in size, so has the number of members that are less wealthy and less prone to support costly regulatory policies; for students of politics, such as Jordan et al., that change in membership reveals how burden-sharing rules must accommodate the underlying differences in preferences and capabilities.

Second, Jordan et al. show that the EU's ability to forge a policy has depended only in part on rising concern about climate change. The really important factor has been success with the broader mission of creating a common European market. When the EU forged a renewable energy strategy (RES), for example, it built the strategy on the idea that more renewable power would increase Europe's energy security, generate jobs, and also lower warming emissions. But the EU wasn't successful in forging much of a common approach until its members had agreed, notably in the 1990s, to give much more power to Brussels. Even then, the policies that have resulted are far from a tightly integrated, Brussels-driven scheme. They are an amalgam of central goals (with a big dose of burden sharing to adjust each country's own effort) and autonomy for member states to act as they see fit.

Third, the compromises needed to craft a common EU policy are especially evident in the emission trading scheme (ETS)—an American idea that Brussels adopted in the late 1990s as the centerpiece of its strategy for controlling emissions. Most economists prefer taxes, and the EU tried taxes with a proposed carbon/energy tax in the early 1990s. But at that time, any such fiscal measure would require unanimous consent, and that doomed the tax. Politically, the ETS was much easier to craft because as an environmental policy, it needed only majority support. Even then, the ETS would have died, however, if Brussels had not left the member states to make the decisions about how to allocate the highly valuable emission credits on their own. The analysis in the Jordan et al. volume adds to a growing literature on the politics of instrument choice. Nearly all that literature suggests that when it comes to market-based instruments, emission trading schemes are politically easier to adopt because they require less visible intervention in the economy.

Fourth, and most importantly, the EU's credibility has risen in tandem with the integration of the European market and the creation of a common body of European law and administrative procedure. Higher credibility has amplified the EU's foreign policy voice. (The decline in the credibility of the United States on global warming and many other matters also helped.) That's the real story here—as the EU has worked through its dilemmas at home, it has been able to exert greater leverage on international agreements. Whether that has led to more effective international agreements to slow climate change is a topic that other studies should explore in more detail.

Inevitably, an edited volume that reflects a big multinational research project will have some flaws. The chief trouble with this book is the lack of a compelling common analytical framework. In addition to the six dilemmas, the authors also explore three policy paradoxes and a host of other side arguments and interesting diversions. Each is based partially on different underlying theories. The result is interesting expert commentary, but the central threads of the book and the project are hard to spot.

The framework, though a bit sprawling, is better able to explain EU policy on mitigating emissions of warming gases. The authors have a harder time identifying and pinning down the forces that explain EU policy on adaptation—in part because adaptation policies are “mainstreamed” into societies and thus harder to spot, and in part because they are less likely to affect the internal trade of goods and services. As Jordan et al. wisely suggest, a Brussels-centered approach to policy has been easier for mitigation because policies that regulate warming gases have a direct impact on trade in goods and services and thus can draw more reliably on the body of EU law (and political support from the member states) anchored in the common market.

Until about two decades ago, the United States was the reliable leader on most international environmental issues. All that has changed, and the EU now usually occupies that spot. Studies like this one from Jordan et al. suggest that this shift is rooted, partially, in the integration of the EU, which has made Europe a much more strategic and powerful actor in foreign policy. What happens at home—especially in a federation such as the EU where the influence of central government is still uneven—determines what governments can get done abroad.