Brumberg Hilary, Hegwood Margaret, Eichhorst Waverly, LoPresti Anna, Erbaugh James T, Kroeger Timm
Department of Environmental Studies, University of Colorado Boulder, Boulder, CO 80303, USA.
Emmett Interdisciplinary Program in Environment and Resources, Doerr School of Sustainability, Stanford University, Stanford, CA 94305, USA.
PNAS Nexus. 2025 Jun 24;4(6):pgaf173. doi: 10.1093/pnasnexus/pgaf173. eCollection 2025 Jun.
Natural climate solutions (NCS) could provide over one-third of the climate mitigation needed between now and 2030 to limit warming below 2°C and support the Sustainable Development Goals. However, large disparities persist between the estimated biophysical climate mitigation potential (CMP) of NCS and their actual implementation. Social, political, informational, and economic factors contribute to this gap, but the spatial distribution of these constraints and their impacts on different NCS pathways remains poorly understood. Understanding these constraints is especially important due to the large uncertainties in NCS CMP and growing research on spatial prioritization of NCS, often based only on biophysical criteria. We identified and mapped nonbiophysical constraints to NCS implementation efficacy by conducting a systematic review of recent peer-reviewed literature across 10 high-CMP NCS pathways. From 1,821 papers, we identified 352 that provided 2,480 observations of 39 unique constraints from 135 countries. We mapped the spatial distribution of these constraints and analyzed patterns across NCS pathways and geographic classifications. Lack of funding, insufficient information on NCS management, and ineffective policies emerged as the most common constraints globally. However, each pathway and geography faced a distinct suite of interrelated constraints spanning multiple categories. These findings highlight the need for context-specific, equitable solutions, likely requiring transdisciplinary approaches and cross-sectoral collaborations. The results could also help increase accuracy of NCS CMP estimates. We discuss how adaptive management may be used for NCS initiatives at any scale to proactively diagnose co-occurring constraints at each implementation phase and to develop integrated, place-based solutions.
自然气候解决方案（NCS）能够提供从现在到2030年间所需气候减缓措施的三分之一以上，以将升温限制在2°C以下，并支持可持续发展目标。然而，NCS的估计生物物理气候减缓潜力（CMP）与其实际实施之间仍存在巨大差距。社会、政治、信息和经济因素导致了这一差距，但这些制约因素的空间分布及其对不同NCS途径的影响仍鲜为人知。鉴于NCS CMP存在很大不确定性，且对NCS空间优先排序的研究不断增加（通常仅基于生物物理标准），了解这些制约因素尤为重要。我们通过对10条高CMP的NCS途径的近期同行评审文献进行系统综述，确定并绘制了影响NCS实施效果的非生物物理制约因素。从1821篇论文中，我们识别出352篇，这些论文提供了来自135个国家的39种独特制约因素的2480条观察结果。我们绘制了这些制约因素的空间分布，并分析了不同NCS途径和地理分类的模式。资金短缺、NCS管理信息不足和政策无效成为全球最常见的制约因素。然而，每条途径和每个地区都面临着一系列独特的、相互关联的制约因素，跨越多个类别。这些发现凸显了针对具体情况的公平解决方案的必要性，这可能需要跨学科方法和跨部门合作。研究结果还可以帮助提高NCS CMP估计的准确性。我们讨论了如何将适应性管理用于任何规模的NCS倡议，以便在每个实施阶段主动诊断同时出现的制约因素，并制定综合的、基于地点的解决方案。
