Data from: Land-based climate solutions for the United States

Meeting end-of-century global warming targets requires aggressive action
on multiple fronts. Recent reports note the futility of addressing
mitigation goals without fully engaging the agricultural sector, yet no
available assessments combine both nature-based solutions (reforestation,
grassland and wetland protection, and agricultural practice change) and
cellulosic bioenergy for a single geographic region. Collectively, these
solutions might offer a suite of climate, biodiversity, and other benefits
greater than either alone. Nature-based solutions are largely constrained
by the duration of carbon accrual in soils and forest biomass; each of
these carbon pools will eventually saturate. Bioenergy solutions can last
indefinitely but carry significant environmental risk if carelessly
deployed. We detail a simplified scenario for the U.S. that illustrates
the benefits of combining approaches. We assign a portion of non-forested
former cropland to bioenergy sufficient to meet projected mid-century
transportation needs, with the remainder assigned to nature-based
solutions such as reforestation. Bottom-up mitigation potentials for the
aggregate contributions of crop, grazing, forest, and bioenergy lands are
assessed by including in a Monte Carlo model conservative ranges for
cost-effective local mitigation capacities, together with ranges for (a)
areal extents that avoid double counting and include realistic adoption
rates and (b) the projected duration of different carbon sinks. The
projected duration illustrates the net effect of eventually saturating
soil carbon pools in the case of most strategies, and additionally
saturating biomass carbon pools in the case of reforestation. Results show
a conservative end-of-century mitigation capacity of 110 (57 – 178) Gt
CO2e for the U.S., ~50% higher than existing estimates that prioritize
nature-based or bioenergy solutions separately. Further research is needed
to shrink uncertainties but there is sufficient confidence in the general
magnitude and direction of a combined approach to plan for deployment now.