Sprenkle-Hyppolite Starry, Griscom Bronson, Griffey Vivian, Munshi Erika, Chapman Melissa
Conservation International, Arlington, VA, USA.
University of California, Santa Barbara, Santa Barbara, CA, USA.
Carbon Balance Manag. 2024 Jul 31;19(1):23. doi: 10.1186/s13021-024-00268-y.
Integrating trees into agricultural landscapes can provide climate mitigation and improves soil fertility, biodiversity habitat, water quality, water flow, and human health, but these benefits must be achieved without reducing agriculture yields. Prior estimates of carbon dioxide (CO) removal potential from increasing tree cover in agriculture assumed a moderate level of woody biomass can be integrated without reducing agricultural production. Instead, we used a Delphi expert elicitation to estimate maximum tree covers for 53 regional cropping and grazing system categories while safeguarding agricultural yields. Comparing these values to baselines and applying spatially explicit tree carbon accumulation rates, we develop global maps of the additional CO removal potential of Tree Cover in Agriculture. We present here the first global spatially explicit datasets calibrated to regional grazing and croplands, estimating opportunities to increase tree cover without reducing yields, therefore avoiding a major cost barrier to restoration: the opportunity cost of CO removal at the expense of agriculture yields.
The global estimated maximum technical CO removal potential is split between croplands (1.86 PgCO yr) and grazing lands (1.45 PgCO yr), with large variances. Tropical/subtropical biomes account for 54% of cropland (2.82 MgCO ha yr, SD = 0.45) and 73% of grazing land potential (1.54 MgCO ha yr, SD = 0.47). Potentials seem to be driven by two characteristics: the opportunity for increase in tree cover and bioclimatic factors affecting CO removal rates.
We find that increasing tree cover in 2.6 billion hectares of agricultural landscapes may remove up to 3.3 billion tons of CO per year - more than the global annual emissions from cars. These Natural Climate Solutions could achieve the Bonn Challenge and add 793 million trees to agricultural landscapes. This is significant for global climate mitigation efforts because it represents a large, relatively inexpensive, additional CO removal opportunity that works within agricultural landscapes and has low economic and social barriers to rapid global scaling. There is an urgent need for policy and incentive systems to encourage the adoption of these practices.
将树木融入农业景观可实现气候缓解，并改善土壤肥力、生物多样性栖息地、水质、水流和人类健康，但这些益处必须在不降低农业产量的情况下实现。先前对农业中增加树木覆盖所带来的二氧化碳（CO₂）去除潜力的估计假设，在不降低农业产量的情况下，可以整合适度水平的木质生物量。相反，我们采用德尔菲专家咨询法来估算53种区域种植和放牧系统类别的最大树木覆盖率，同时保障农业产量。将这些数值与基线进行比较，并应用空间明确的树木碳积累率，我们绘制了农业树木覆盖额外CO₂去除潜力的全球地图。我们在此展示了首个针对区域牧场和农田校准的全球空间明确数据集，估算了在不降低产量的情况下增加树木覆盖的机会，从而避免了恢复的一个主要成本障碍：以牺牲农业产量为代价进行CO₂去除的机会成本。
全球估计的最大技术CO₂去除潜力在农田（1.86PgCO₂/年）和牧场（1.45PgCO₂/年）之间分配，差异较大。热带/亚热带生物群落占农田潜力的54%（2.82MgCO₂/公顷/年，标准差=0.45）和牧场潜力的73%（1.54MgCO₂/公顷/年，标准差=0.47）。潜力似乎由两个特征驱动：树木覆盖增加的机会以及影响CO₂去除率的生物气候因素。
我们发现，在26亿公顷的农业景观中增加树木覆盖每年可能去除多达33亿吨CO₂，超过全球汽车的年排放量。这些自然气候解决方案可以实现波恩挑战，并在农业景观中新增7.93亿棵树。这对全球气候缓解努力具有重要意义，因为它代表了一个大规模、相对低成本的额外CO₂去除机会，在农业景观中发挥作用，并且在全球快速推广方面具有较低的经济和社会障碍。迫切需要政策和激励系统来鼓励采用这些做法。
