Deployment of hydrogen in hard-to-abate transport sectors under limited carbon dioxide removal (CDR): Implications on global energy-land-water system

Prioritizing Non-Carbon Dioxide Removal Mitigation Strategies Could Reduce the Negative Impacts Associated with Large-Scale Reliance on Negative Emissions

“…Between 2025 and 2050, there will be rapid decarbonization especially in the building (∼95%), power (∼90%), and transport sectors (∼60%) by deploying 1 GtCO 2 of novel CDR by 2050, compared to relatively slower decarbonization rates of approximately 30%, 65%, and 5%, respectively, when the world bets on deploying over 20 GtCO 2 of novel CDR by mid-century. Hard-to-abate sectors within the transport and industry sectors would make decarbonization increasingly slower under multi-Gt CDR pathways. , It is worth noting that DACCS requires significant amounts of energy, which could increase emissions if supplied by fossil fuels. , ERW could potentially increase emissions from water and energy generation. GHG emissions are linked to biochar production, and BECCS comes with significant land requirements and can lead to higher emissions depending on factors such as the scale of deployment, conversion technology, fuel displacement, and the methods and locations of biomass production .…”

“…Hard-to-abate sectors within the transport and industry sectors would make decarbonization increasingly slower under multi-Gt CDR pathways. 14,38 It is worth noting that DACCS requires significant amounts of energy, which could increase emissions if supplied by fossil fuels. 12,14 ERW could potentially increase emissions from water and energy generation.…”

“…It is also worth noting that under very limited availability of negative emissions, bioenergy consumption tends to increase significantly to accelerate deep decarbonization. 38 An increase in bioenergy consumption under limited CDR could lead to higher land allocation for cultivating bioenergy crops at the expense of other agricultural lands and water consumption in the process. As such, limiting CDR excessively could indirectly create other sustainability issues regarding food and water security.…”

“…When deployed responsibly and at scale later this century, CDR can make net zero goals more feasible. 38 This study explores scenarios that prioritize non-CDR mitigation over CDR deployment to quantify the implications of this trade-off on the global energy−land−water system. CDR deployment in the current study has been significantly limited by assuming that the world may not reach tens of Gt scale of CDR by 2050, as proposed in previous studies.…”

“…It is much more straightforward and easier to stop emitting in the first place, compared to trying to remove CO 2 from the atmosphere to achieve climate goals. When deployed responsibly and at scale later this century, CDR can make net zero goals more feasible …”