This study discusses the role of Carbon dioxide removal (CDR) in minimizing global warming projections. CDR is a critical tool in all plans to limit warming to below 1.5 °C, but only a few CDR pathways have been incorporated into integrated assessment models upon which international climate policy deliberations rely. A more diverse set of CDR approaches could have important benefits and costs for energy–water–land systems.
Here we use an integrated assessment model to assess a complete suite of CDR approaches and consider three main scenarios: 1) no climate policy is applied; 2) CO2 emissions are constrained to limit warming to below 1.5 °C in 2100; 3) the 1.5 °C emissions constraint from scenario 2 is applied along with changes to behavior and technology that reduce greenhouse gas (GHG) emissions regardless of carbon policy.
The article presents detailed findings for emissions and removals, primary and final energy, land use, water, and sensitivity analyses. Ultimately, they found that ambitious cross-sectoral efforts to decrease residual GHG emissions reduce but do not eliminate the requirement for CDR. The authors noted that CDR at anywhere approaching the scales projected in their study would require strong policy incentives, extensive monitoring and verification, and public investment at levels similar to landfills and wastewater treatment facilities, which cannot be achieved without substantial societal investment.
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