Climate strategies result in considerable problem shifting

Policies and strategies for climate change mitigation are intended to transform society in terms of activities, use of materials, and sources of energy. Transformation on this scale is likely to shift pressures from climate change to other environmental domains. For mitigation to be sustainable in a broad environmental sense, it must address or anticipate the risk of such environmental problem shifting (EPS). While this issue has been recognized in the case of certain climate change mitigation options, a broad and encompassing overview of EPS is lacking. This study offers a systematic mapping of EPS. 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. Based on screening a total of 10,997 articles, 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. The mitigation options most commonly studied are bioenergy [75 studies] and carbon dioxide removal [61] while the most frequent environmental shifts are to freshwater use [101] and land use [85]. Regarding methods, we find that some studies systematically overestimate EPS by not accounting for the environmental benefits of reduced climate change. We therefore propose to conceptually clarify the different ways of estimating EPS by distinguishing between gross, net, and relative shifting. Regarding terminology, we identified 21 terms that have been used to refer to EPS. To clarify their differences and to demarcate EPS, we presented a typology of secondary policy effects. We argue that the term "environmental problem shifting" is the most accurate term to describe shifts from one environmental problem (in our case climate change) to another.