| 摘要 |
Environmental economics has investigated optimal policies that incentivize the reduction of
environmental externalities in great detail, while clean-up technologies that undo pollution have
received little attention. Current projections for climate policy strategies, however, frequently rely
substantially on clean-up by including the use of various carbon dioxide removal technologies, or
CDRs (IPCC 2018). For limiting global warming to 1.5°C, for example, up to half of current carbon
emissions have to be removed annually in the second half of the 21st century (Rogelj 2015).
This adds complications to the challenge of finding efficient climate policies that go beyond the
state of knowledge in environmental economics: with a comprehensive carbon pricing regime at
work, net negative emissions turn tax revenues into subsidy expenditures, putting stress on the
fiscal budget instead of generating revenues. Moreover, removing carbon dioxide rather than
mitigating emissions could affect leakage related to shifting fossil resource supply or trade of
carbon-intensive goods. Finally, when CDR technologies are land-intensive, their implementation
becomes intertwined with food production and land use change, which has implications for the real
income distribution as well as land-use emissions in non-regulated jurisdictions.
The research we propose sheds light on the challenges of optimal policies on clean-up
technologies like CDR by considering broader economic aspects like fiscal policy interactions,
distributional aspects and jurisdictional spillovers. We contribute in three ways: (1) We advance the
understanding of clean-up policies as a complement to and substitute for pricing emissions in a
first-best setting, (2) we analyze cleanup policies in the context of distortionary income taxation and
distributional consideration, and (3) we investigate CDR policies in fragmented policy regimes that
are subject to carbon leakage. Overall, in our research we link the analysis of policy instruments for
cleanup technologies to the existing strands of environmental and public economics literature that
focuses on taxing externalities.
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