Researchers at the University’s Global Academy of Agriculture and Food Systems are developing bio-economic models to help governments and companies understand the cost-effectiveness of measures to reduce the environmental impact of beef production.
粮食生产贡献了全球温室气体排放的37%, 其中，动物性食品占三分之一以上. Such figures have led to calls for reducing meat consumption to fight climate change. 但这对畜牧业有什么影响呢?
Although there has been a shift towards plant-based foods and more sustainable sources of animal protein, 比如鸡和养鱼, 在高收入国家, the demand for meat from low- and middle-income countries (LMICs) is continuing to rise.
“世界不太可能朝着零消耗所有动物蛋白的方向迭代,多米尼克·莫兰说, Professor of Agricultural and Resource Economics in the University’s Global Academy of Agriculture and Food Systems. “九游会官方在线需要优化牲畜系统的生产率, especially in those parts of the 世界 that are able to produce meat with lower emission intensity than others,”他认为.
畜牧业维持着许多人的生计, 特别是在经济选择有限的中低收入国家. Sustainable intensification of livestock systems in these countries could tackle both food security and conservation objectives.
“The carbon footprint for livestock production varies a lot,” 说 Dr Rafael De Oliveira席尔瓦, 全球农业与粮食系统学院校长研究员. “如果考虑到碳封存，它可能是零，甚至是负的, 但如果这与森林砍伐有关, 它可以超过100 千克二氧化碳当量 每公斤肉.”
通过使用 创新的生物经济模型 德·奥利维拉·席尔瓦和莫兰， 可以分析 土地利用变化的影响, 土地管理和肉类需求, 以及采用新技术, 牛肉生产的温室气体排放.
In 2020, 巴西是世界上最大的牛肉出口国, 占全球牛肉出口总额的近20%. 它也是世界上生物多样性最丰富的国家 世界这里的森林覆盖率最高，约占亚马逊雨林的60% 热带雨林.
As beef production grows so does 的需要 for pastures, which is a major driver of deforestation. Urgent measures are required if Brazil is to reconcile its international commitments to biodiversity conservation while also meeting the global demand for beef.
“巴西为自己设定了非常雄心勃勃的目标，承诺减排 到2030年，温室气体排放量将比2005年减少43%, 主要是通过停止亚马逊森林砍伐,De Oliveira席尔瓦博士解释道.
He has been working with the Ministry for Agriculture in Brazil (MAPA) to help the Brazilian Government achieve the pledges it made at COP21 and the country's Nationally Determined Contribution to the Paris Climate Agreement (2015). “We were contacted by the Ministry of Agriculture because they wanted to know how beef production systems would have to adapt to reconcile demand projections with deforestation targets.”
Dr De Oliveira席尔瓦 has developed bio-economic models that compare the cost-effectiveness of MAPA’s sustainable agricultural intensification (SAI) policies for livestock production. The aim of these policies is to reconcile a desire for increased productivity (output per hectare) while simultaneously reducing greenhouse gas emissions.
各种温室气体缓解措施的影响, 包括饲料添加剂和硝化抑制剂的使用, 在塞拉多, the central Brazilian savannah which supports more than 30 per cent of Brazil's cattle herd. 结果表明:通过化学和机械处理对草地进行修复 以促进草的生长 这是迄今为止最有效的减排措施吗.
“Our analysis indicates that Brazil’s greenhouse gas emission targets can be achieved by restoring 15,000,000-20,000,000公顷退化的牧场, 约占巴西牧场的10%,” Dr De Oliveira席尔瓦 说.
Restored pasturelands reduce greenhouse gas emissions by sequestering carbon into the soil and increasing the efficiency of cattle feed production, 是什么导致了牛肉生产成本的节省. 通过避免排放，可以进一步减少温室气体排放 的需要 清除额外的森林区域用于放牧.
推动牧场恢复, MAPA’s Low Carbon Agriculture programme has been providing financial incentives for 农民 since 2010. Dr De Oliveira席尔瓦’s work demonstrates the effectiveness of the scheme and supports investing in a second phase 2020年至2030年.
“在缓慢的开始之后, the Low Carbon Agriculture programme has gained traction and today lots of 农民 are 采取措施恢复巴西的牧场，”他说.
除了告知政府政策之外, De Oliveira席尔瓦博士正在巴西JBS公司工作, 世界上最大的肉类加工公司之一, 制定温室气体减排计划，在2040年前实现净零排放. “九游会官方在线正在帮助JBS确定措施，而不仅仅是减少二氧化碳, 还有甲烷排放.”
在100年的时间尺度上, 甲烷的全球变暖潜力是二氧化碳的28倍多. 认识到全球应对甲烷采取行动的必要性, 在2021年的第26届联合国气候大会上, more than 100 countries (including Brazil) pledged to cut methane emissions by 30 per cent by 2030.
“Reducing methane emissions is more complicated than reducing carbon dioxide emissions, 因为要求不同, 更昂贵的技术,De Oliveira席尔瓦博士解释道.
选择育种, feed supplements and some promising additives can help cattle use feed more efficiently and reduce their methane production, 但这些方法尚未被广泛采用.
While most models for calculating the environmental impact of meat production provide a fixed number, the model developed by Dr De Oliveira席尔瓦 can capture the effects of changes in demand.
在巴西, 如果对牛肉的需求增加, 农民 have to intensify production in the context of deforestation-control policies, which stimulate the adoption of pasture restoration measures resulting in reduced greenhouse gas emissions. 相反, 和直觉相反, reduced demand for beef could lead to an increase in emissions due to reduced incentives to restore pastures.
Applying these models to other beef production systems around the 世界 could shed light on how to mitigate the environmental impact of production and still meet demand. Professor Moran has recently embarked on a BBSRC-funded project Transforming the Debate about livestock systems transformation, that will examine the future of the UK’s livestock sector taking into consideration changes in consumer preferences and emerging technologies, 比如遗传学和育种技术. 这有可能显著减少温室气体排放.
“九游会官方在线期待支持行业利益相关者进行知情对话, 包括科学家, 农民, 处理器, 零售商, 消费者, 投资者和政策制定者, and will seek to find consensus on how livestock production systems will need to change to meet the UK’s net-zero targets,莫兰教授说.