Environmental problem shifting from climate change mitigation: A mapping review.

Climate change mitigation will trigger major changes in human activity, energy systems, and material use, potentially shifting pressure from climate change to other environmental problems. We provide a comprehensive overview of such "environmental problem shifting" (EPS). While there is considerable research on this issue, studies are scattered across research fields and use a wide range of terms with blurred conceptual boundaries, such as trade-off, side effect, and spillover. We identify 506 relevant studies on EPS of which 311 are empirical, 47 are conceptual-theoretical, and 148 are synthetic studies or reviews of a particular mitigation option. A systematic mapping of the empirical studies reveals 128 distinct shifts from 22 categories of mitigation options to 10 environmental impacts. A comparison with the recent IPCC report indicates that EPS literature does not cover all mitigation options. Moreover, some studies systematically overestimate EPS by not accounting for the environmental benefits of reduced climate change. We propose to conceptually clarify the different ways of estimating EPS by distinguishing between gross, net, and relative shifting. Finally, the ubiquity of EPS calls for policy design which ensures climate change mitigation that minimizes unsustainability across multiple environmental dimensions. To achieve this, policymakers can regulate mitigation options-for example, in their choice of technology or location-and implement complementary environmental policies.

Prioritize carbon pricing over fossil-fuel subsidy reform.

While many climate activist groups enthusiastically advocate for the removal of fossil-fuel subsidies, we argue that this overstates both the climate effectiveness and political feasibility of such a strategy. Through synthesizing information from various global studies, we show that subsidies contribute to a relatively small portion of climate change and local externality problems, likely accounting for around 1%. We further argue that reform of fossil-fuel subsidies is hampered by various political and social factors, more so than the diffusion of carbon pricing. Based on these results, we argue that the far greater problem of unpriced externalities warrants a redirection or expansion of the enthusiasm for subsidy reform toward carbon pricing. This makes sense also as subsidy reform and carbon pricing essentially represent two sides of the same coin since both contribute to climate mitigation by raising fossil-fuel prices.