气候变化、土地退化和粮食安全问题:关联机制与解决途径

Abstract

气候变化影响全球食物、水、能源生产和消费，并直接威胁国家和区域粮食安全和社会稳定，相关研究关系到国计民生与全球可持续发展。土地退化是近年来国际研究热点，IPCC、IPBES、UNCCD等都开展了土地退化的专题评估，高度关注土地退化的动态、趋势、影响及响应。尽管气候变化与土地退化具有密切关联，但对其复杂关联机制及解决途径缺乏系统的研究。IPCC于2017-2019年开展了第一次气候变化和土地退化评估，并于2019年8月发布了《气候变化与土地》特别报告（SRCCL）。基于此评估报告，对其中气候变化、土地退化与粮食安全之间的关联机制、未来的变化趋势、可能的影响及对策等进行了系统的论述。特别报告的重要贡献在于其厘清了气候变化与土地退化之间的复杂关联与反馈机制，进一步证实土地利用是导致气候变化的主要因素，指出日益增加的人口压力和粮食消费加剧了土地的退化和气候变化。尽管如此，特别报告也强调土地可为当前全球变暖、生物多样性减少等诸多环境问题提供解决方案，并重点指出改变人类饮食结构和消费习惯具有能够同时应对气候变化和土地退化的双赢效果。将全球升温幅度限制在1.5℃以内的窗口期正在迅速缩短，要解决当前日益凸显的气候变化和土地退化问题，需要推动食物消费的转型、降低碳排放、实施可持续土地管理，促进可同时减缓气候变化和土地退化的协同行动，科学合理的应用负排放和碳储存技术。;Climate change affects global production and consumption of food, water and energy, and directly threatens national and regional food security and social stability, thus the relative research is detrimental to the national human prosperity and global sustainable development. Land degradation is an international hot topic in recent years. Many international platforms like IPCC, IPBES and UNCCD have done assessments on the land degradation, especially have focused on the dynamics, trends, impacts, and responses. Although climate change and land degradation are interconnected, there is a lack of understanding of their complex relations and solutions. IPCC has performed its first climate change and land degradation assessment from 2017 to 2019, and released the special report in August of 2019. Based on the report, here we analyzed the complex interaction and feedback between climate change and land degradation, their potential change in the future, and solutions to deal with these problems. The main contribution of the special report is that it clarified the linkages and feedbacks between climate change and land degradation, further recognized that land use change was the main driver of climate change, and indicated that the increasing human pressure and food consumption aggravated climate change and land degradation. However, land is also a solution to many environmental problems we faced today. Changing the human diet can address climate change and land degradation simultaneously. The window of opportunity to restrict global warming with 1.5℃ is rapidly shrinking. We need to promote the diet transition, reduce carbon emission, implement sustainable land management, enable synergies between climate change mitigation and land restoration, and apply smart carbon dioxide removal technologies in order to address the worsening climate change and land degradation.