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WANG YIMENG/FOR CHINA DAILY
近年来，气候变化成为全球关注的公共议题。2022年11月6日，《联合国气候变化框架公约》第二十七次缔约方大会（COP27）在埃及沙姆沙伊赫召开，讨论应对全球气候变化的实际行动和方案，推动全球气候治理。
文章指出，全球范围内的温室气体减排工作仍然任重道远。正如今年10月联合国环境规划署发布的《2022年排放差距报告》显示，国际社会远远没有达到《巴黎协定》的目标，将全球变暖限制在“远低于2℃，最好是1.5℃”的目标遥遥无期。因此，亟待进行全系统转型，才能实现2030年的减排目标。
文章指出，食物系统既是温室气体排放的贡献者，也是实现“双碳”目标和减缓气候变化的重要部分。从全球来看，目前，食物系统约占温室气体总排放量的三分之一，其最大来源是农业生产（39%），包括化肥等投入品的施用，其次是土地利用的变化（32%），以及供应链活动（29%）。后者包括零售、运输、消费、燃料生产、废弃物管理、工业加工和包装。因而转型食物系统对改善气候变化和环境退化至关重要。就转型路径而言，需求侧转型、保护自然生态系统、改善粮食生产和食品价值链脱碳等措施是具有巨大减排潜力的可行性路径。
文章认为，应对气候变化，中国是积极的参与者，已承诺将力争2030年前实现碳达峰、2060年前实现碳中和。在“双碳”目标下，食物系统的碳减排贡献不容忽视。2018年中国食物系统温室气体排放高达10.9亿吨 CO2 当量，约占温室气体排放总量的10%。就实现2060年碳中和目标的中国食物系统转型路径选择而言，在保障粮食安全的前提下，采取提高农业生产技术、减少食物损耗和浪费、调整膳食结构等综合措施均具有显著的减排效果。
据《2021中国与全球食物政策报告》测算，在农作物技术和畜牧业技术提高情景下，到2060年，农业温室气体排放量将分别减少7-16个百分点和9-23个百分点。同时，减少食物损耗和浪费情景下，2060年将减少4-7个百分点。调整膳食结构是减少个人和家庭温室气体排放的最经济有效的减排方案，可在2060年将温室气体排放量减少16-24个百分点，例如提高能源效率和优化能源消耗结构。综合以上所有措施，2060年可减少食物系统温室气体排放量29-55个百分点。
文章建议，应对气候变化是全人类的共同事业，需要切实采取行动推动转型。
以下是文章全文内容：
Transforming global food systems would produce a large reduction in GHG emissions
Heads of State, ministers, and negotiators are now meeting in Sharm el-Sheikh, Egypt, for the largest annual gathering on climate action. The 27th Conference of the Parties to the United Nations Framework Convention on Climate Change (COP 27) discusses issues critical to tackling the climate emergency, from urgently reducing greenhouse gas emissions, building resilience, and adapting to the inevitable impacts of climate change, to delivering on the commitments to finance climate action in developing countries.
The recently released United Nations Emissions Gap Report shows a very disappointing picture. Global GHG emissions continued to increase up to 2019. The emissions in 2020 declined due to the COVID-19 pandemic, but rebounded in 2021, setting a new record at the level of 52.8 gigatons of CO2 equivalent (GtCO2eq). Emissions under current policies are projected to continue to increase and are forecast to reach 58 GtCO2eq in 2030. Without additional actions, current policies will lead to global warming of 2.8 C over this century. A 2.8 degree increase is unbearable for human life. Thus, in 2015 countries committed to making efforts to limit global warming to below 2.0 C and preferably 1.5 C, the so-called Paris Agreement.
Despite all countries at the COP 26 in Glasgow, Scotland, strengthening their intended Nationally Determined Contributions to tackle emissions and mitigate climate change, progress is hugely insufficient, with the emissions reduction of only 0.5 GtCO2eq, less than 1 percent of the projected global emissions in 2030. It is far from the goal and the emissions gap remains high and the world is not on track to meet the targets of the Paris Agreement. Urgent, broad-based, economy-wide transformations are required to drastically cut GHG emissions to avoid the climate catastrophe.
Food systems are major contributors not only to climate change, but also to land-use change and biodiversity loss, the depletion of freshwater resources and the pollution of aquatic and terrestrial ecosystems. Adopting a food systems lens implies a cross-sectoral approach that explicitly connects supply and demand sides, and all actors in the food supply chain. It facilitates identifying synergies and trade-offs across interconnected environmental, health and economic dimensions.
Globally, food system emissions account for one-third of the total GHG emissions or 18 GtCO2eq per year. The largest source is from agricultural production (39 percent), including the intermediate inputs such as fertilizers, followed by changes in land use (32 percent), and supply chain activities (29 percent), including retail, transport, consumption, fuel production, waste management, industrial processes and packaging. Food system emissions will continue to increase, especially from the food supply chain. The emissions could almost double if nothing is done, and are projected to increase by up to 60 to 90 percent between 2010 and 2050.
Food system emissions could prevent achieving the well below 2 C, preferably 1.5 C goal by the end of the century, even if fossil fuel emissions were quickly reduced. The global food system must be transformed rapidly to produce a large emissions reduction and narrow the emissions gap. A range of transformation domains have been identified to cut down the emissions from food systems. The potential to reduce GHG emissions is up to 24.7 GtCO2eq/year through the transformations of the demand-side, protecting natural ecosystems, improving food production and decarbonizing the food value chain. The demand-side changes include dietary changes toward sustainable and nutritionally balanced diets, and reductions in food loss and waste. The protection of natural ecosystems includes reductions in deforestation for agriculture and degradation of agricultural land, and improvements in food production which includes changes in the composition of animal feeds, better rice management, better manure management, and improvements in crop nutrient management, and decarbonizing the food supply chain.
China has made an important commitment to realize its carbon peak before 2030 and achieve carbon neutrality before 2060. Food systems can make a significant contribution to these targets. GHG emissions from Chinese food systems are as high as 1.09 billion tons CO2eq, which accounted for about 10 percent of the country's emissions in 2018.
Ensuring food security must be the national top priority, but measures such as improving agricultural production technologies, reducing food loss and waste, and changes to dietary patterns are also critical for reducing GHG emissions. Improvements in agricultural production technologies are the most effective stand-alone measures. Many technical measures, such as the improvement of chemical fertilizer use efficiency, the feed conversion rate, and the utilization of livestock manure as a resource have great potential to reduce GHG emissions. According to the 2021 China and Global Food Policy Report, GHG emissions reduction from agricultural activities by 2060 will be 7 to 16 percent and 9 to 23 percent under the scenario of crop technology and the scenario of livestock technology, respectively. The reduction of food loss and waste is also conducive to reducing GHG emissions, with a decrease of 4 to 7 percent in 2060. Dietary changes are the most economically effective abatement options to reduce GHG emissions by individuals and households which can cut GHG emissions by 16 to 24 percent in 2060.GHG emissions from food systems energy consumption can be significantly reduced through comprehensive emissions reduction measures, such as the improvement of energy efficiency and the optimization of the energy consumption structure. Combining all the above measures could cut food systems GHG emissions by 29 to 55 percent in 2060.
Actors from all segments of society need to take action to drive transformation and overcome barriers. The government could facilitate this transition by reforming subsidy and tax schemes. The private sector can reduce food loss and waste, use renewable energy, develop new types of food, and reduce carbon emissions. Individual citizens can change their lifestyles to make food choices for environmental sustainability and emissions reduction.
Fan Shenggen is the dean of the Academy of Global Food Economics and Policy and chair professor at China Agricultural University. Zhang Yumei is a professor of the Academy of Global Food Economics and Policy at China Agricultural University. The authors contributed this article to China Watch, a think tank powered by China Daily.
The views do not necessarily reflect those of China Daily.
Contact the editor at editor@chinawatch.cn