The remaining carbon budget for limiting global warming to 1.5°C will likely be exhausted within this decade1,2. Carbon debt3 generated thereafter will need to be compensated by net negative emissions4. However, economic policy instruments to guarantee potentially very costly net carbon-dioxide removal (CDR) have not yet been devised. Here, we propose intertemporal instruments to provide the basis for widely applied carbon taxes and emission trading systems to finance a net negative carbon economy5. We investigate an idealized market approach to incentivize repayment of previously accrued carbon debt by establishing emitters’ responsibility for net carbon removal through ‘Carbon Removal Obligations’ (CROs). Inherent risks, such as the default risk of carbon debtors, are addressed by pricing atmospheric CO2 storage through interest on carbon debt. In contrast to the prevailing literature on emission pathways, we find that interest payments for CROs induce substantially more ambitious near-term decarbonization complemented by earlier and less aggressive deployment of CDR. We conclude that CROs will need to become an integral part of the global climate policy mix if we are to ensure the viability of ambitious climate targets and an equitable distribution of mitigation efforts across generations.
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This file contains a graphical representation of all 2°C (RCP2.6) emission pathways discussed in the Results (specifically in Figure 3).
This file contains the data of all 2°C (RCP2.6) pathways discussed in the Results as Excel sheet.
SI1.3 contains a graphical representation of all 1.5°C (RCP1.9) emission pathways discussed in the Results (specifically in Figure 4 and Extended Data Figures 7-9).
This file contains the data of all 1.5°C (RCP1.9) pathways discussed in the Results as Excel sheet.
This file contains a graphical representation of the marginal abatement cost (MAC) curves used in the numerical model of this study. The parameters of the MAC curves can be retrieved with the R package provided for using the numerical model.
This file illustrates carbon prices from the SSP scenarios compared to carbon prices and MAC from the numerical model of this study.
This file illustrates consumption loss and GDP loss from the SSP scenarios compared to abatement costs from the numerical model of this study.
This file illustrates net emissions from the SSP scenarios compared to net emissions from the numerical model of this study.
This file contains the analytical methods necessary to derive equation  in the Methods section.
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Bednar, J., Obersteiner, M., Baklanov, A. et al. Operationalizing the net-negative carbon economy. Nature (2021). https://doi.org/10.1038/s41586-021-03723-9