Manuel Linsenmeier, Mr. Adil Mohommad, and Gregor Schwerhoff
In this paper, we study the international diffusion of carbon pricing policies. In the first part, we empirically examine to what extent the adoption of carbon pricing in a given country can explain the subsequent adoption of the same policy in other countries. In the second part, we quantify the global benefits of policy diffusion in terms of greenhouse gas emission reductions elsewhere. To do so, we combine a large international dataset on carbon pricing with several other datasets. For causal identification, we estimate semi-parametric Cox proportional hazard models. We find robust and statistically significant evidence for policy diffusion.
Manuel Linsenmeier, Mr. Adil Mohommad, and Gregor Schwerhoff
Carbon pricing is considered the most efficient policy to reduce greenhouse gas emissions but it has also been conjectured that other policies need to be implemented first to remove certain economic and political barriers to stringent climate policy. Here, we examine empirical evidence on the the sequence of policy adoption and climate policy portfolios of G20 economies and other major emitters that eventually implemented a national carbon price. We find that all countries adopted carbon pricing late in their instrument sequence after the adoption of (almost) all other instrument types. Furthermore, we find that countries that adopted carbon pricing in a given year had significantly larger climate policy portfolios than those that did not. In the last part of the paper, we examine heterogeneity among countries that eventually adopted a carbon price. We find large variation in the size of policy portfolios of adopters of carbon pricing, with more recent adopters appearing to have introduced carbon pricing with smaller portfolios. Furthermore, countries that adopted carbon pricing with larger policy portfolios tended to implement a higher carbon price. Overall, our results thus suggest that policy sequencing played an important role in climate policy, specifically the adoption of carbon pricing, over the last 20 years.
Jean Chateau, Ms. Florence Jaumotte, and Gregor Schwerhoff
This paper discusses and analyzes various international mechanisms to scale up global action on climate mitigation and address the policy gap in this area. Despite the new commitments made at COP 26, there is still an ambition and a policy gap at the global level to keep temperature increases below the 2°C agreed in Paris. Avoiding the worst outcomes of climate change requires an urgent scaling up of climate policies. Recent policy proposals include the idea of common minimum carbon prices, which underlie the IMF’s international carbon price proposal (Parry, Black, and Roaf 2021) and the climate club proposal of the German government. While global carbon prices are not a new idea, the new elements are the use of carbon price floors—which allow countries to do more if they wish—and the differentiation of carbon price floors by level of development. In the absence of international coordination, countries with ambitious climate policies are considering introducing a border carbon adjustment mechanism to prevent domestic producers from being at a competitive disadvantage due to more ambitious domestic climate policies. An interesting question from the global perspective is whether border carbon adjustment would deliver substantial additional emissions reductions or incentivize other countries to join a carbon price floor agreement.
To reach the global net-zero goal, the level of carbon emissions has to fall substantially at speed rarely seen in history, highlighting the need to identify structural breaks in carbon emission patterns and understand forces that could bring about such breaks. In this paper, we identify and analyze structural breaks using machine learning methodologies. We find that downward trend shifts in carbon emissions since 1965 are rare, and most trend shifts are associated with non-climate structural factors (such as a change in the economic structure) rather than with climate policies. While we do not explicitly analyze the optimal mix between climate and non-climate policies, our findings highlight the importance of the nonclimate policies in reducing carbon emissions. On the methodology front, our paper contributes to the climate toolbox by identifying country-specific structural breaks in emissions for top 20 emitters based on a user-friendly machine-learning tool and interpreting the results using a decomposition of carbon emission ( Kaya Identity).
Mr. Philip Barrett, Katharina Bergant, Jean Chateau, and Rui Mano
The run up to the 26th Climate Change Conference has brought tackling climate change to the fore of global policy making. In this context, the U.S. administration has recently unveiled new climate targets. This paper elaborates on the administration’s plans and uses two models developed at the IMF to illustrate key macro-climate trade-offs. First, a model with endogenous fuel-specific technological change shows that subsidies cannot substitute for explicit carbon pricing and that even a moderate carbon tax can greatly economize on the overall fiscal cost of the package. Second, a rich sectoral model shows that there are only very marginal economic costs from front-loading the decarbonization of the power sector but there are large accompanying environmental benefits. Regulations can be effective in the power sector because they provide an appropriate shadow cost to carbon. However, a carbon tax would still be more efficient and easier to administer. Finally, as the economy transitions away from fossil-fueled power generation, there would be a significant reallocation of labor across sectors and locations that would need to be handled carefully to limit the social costs of the transition.
In short, yes. I use a multi-region integrated assessment model with fuel-specific endogenous technical change to examine the impact of Europe and China reducing emissions to zero by mid-century. Without international technological diffusion this is insufficient to avoid catastrophic climate change. But when innovation can diffuse overseas, long-run temperature increases are limited to 3 degrees. This occurs because policy not only encourages green innovations but also dissuades dirty innovations which would otherwise spread. The most effective policy package in emissions-reducing regions is a research subsidy funded by a carbon tax, driven in the short term by the direct effect of the carbon tax on the composition of energy, and later by innovation induced by research subsidies. Green production subsidies are ineffective because they undermine incentives for innovation.
International Monetary Fund. Strategy, Policy, & Review Department
While the IMF has been involved in the climate debate since at least 2008, a systematic account of how to integrate climate change into surveillance has been lacking to date. This paper seeks to fill the gap. It argues that domestic policy challenges related to climate change—such as adaptation efforts for climate vulnerable countries, or policies to deliver a country’s Nationally Determined Contribution under the Paris climate accord—are covered by the IMF’s bilateral surveillance mandate and therefore valid topics for Article IV consultations wherever these challenges cross the threshold of macro-criticality. Climate change mitigation is a global policy challenge and therefore falls under multilateral surveillance. The paper proposes a pragmatic approach that focusses especially on the mitigation efforts of the 20 largest emitters of greenhouse gases.