Land-based climate solutions for the United States

Area of Science:

• Environmental Science
• Climate Change Mitigation
• Agricultural Science

Background:

• Meeting end-of-century global warming targets necessitates aggressive, multi-faceted climate action.
• Previous assessments have not integrated nature-based solutions (NBS) and cellulosic bioenergy for regional climate mitigation.
• NBS carbon sequestration is limited by pool saturation, while bioenergy offers indefinite potential but carries environmental risks.

Purpose of the Study:

• To assess the combined mitigation potential of NBS and cellulosic bioenergy in the United States.
• To illustrate the synergistic benefits of integrating these approaches for climate, biodiversity, and other ecosystem services.

Main Methods:

• A simplified U.S. scenario allocating former cropland to bioenergy and NBS (e.g., reforestation).
• Monte Carlo modeling to assess bottom-up mitigation potentials considering cost-effective capacities, realistic adoption rates, and carbon sink durations.
• Inclusion of carbon pool saturation effects for both soil and biomass.

Main Results:

• The combined approach yields a conservative end-of-century mitigation capacity of 110 Gt CO2e (57-178 Gt CO2e) for the U.S.
• This represents approximately a 50% increase compared to estimates focusing solely on NBS or bioenergy.
• Synergistic effects enhance overall carbon sequestration potential beyond individual strategy capacities.

Conclusions:

• Integrating nature-based solutions and cellulosic bioenergy provides a significantly more effective strategy for U.S. climate mitigation.
• The combined approach offers greater mitigation capacity than strategies implemented in isolation.
• Sufficient confidence exists to plan for the deployment of combined strategies, despite the need for further uncertainty reduction.