Soil carbon sequestration in grazing systems: managing expectations
Soil carbon sequestration in grazing systems: managing expectations
复制标题
放牧系统中的土壤固碳：管理预期
DOI：
10.1007/s10584-020-02673-x
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发表时间：
2020-02-05
期刊：
影响因子：
4.8
通讯作者：
Garnett, Tara
中科院分区：
文献类型：
--
作者：
Godde, Cecile M.;de Boer, Imke J. M.;Garnett, Tara
放牧制度排放温室气体，在特定的农业生态条件下，土壤固碳可以部分或全部抵消这些气体。然而，任何固碳都是有时间限制的、可逆的，而且在全球一级，放牧系统的排放量超过了固碳。因此，放牧系统是全球气候变化的净贡献者，任何减缓努力都需要考虑到关键过程的时间尺度。如果不这样做，就会导致对放牧系统中土壤碳管理作为缓解战略的不切实际的期望。保护牧场的大量碳储存也至关重要，以避免更多的二氧化碳排放造成进一步的气候变化。尽管牧场土壤固碳具有时间限制和可逆性，但如果固碳具有环境和农业效益，并具有潜力，特别是在退化土地上，应促进固碳，以提高将全球升温限制在2摄氏度或最好是1.5摄氏度以下的可行性。一些同行评审的封存估计与10-20年内其他粮食系统缓解方案的数量级相似，例如将粮食损失和浪费减少15%或使饮食与当前健康相关的饮食建议保持一致。然而，在进行此类比较时应谨慎，因为缓解估计与很大的不确定性相关，并且最终将取决于经济成本效益关系、实施的可行性和考虑的时间范围。
Grazing systems emit greenhouse gases, which can, under specific agro-ecological conditions, be partly or entirely offset by soil carbon sequestration. However, any sequestration is time-limited, reversible, and at a global level outweighed by emissions from grazing systems. Thus, grazing systems are globally a net contributor to climate change and the time scale of key processes needs to be factored into any mitigation efforts. Failing to do so leads to unrealistic expectations of soil carbon management in grazing systems as a mitigation strategy. Protecting the large carbon stocks in grazing lands is also essential in order to avoid further climate change from additional CO2 release. Despite the time-limited and reversible nature of soil carbon sequestration in grazing lands, sequestration should be promoted in cases where it delivers environmental and agronomic benefits as well as for its potential, particularly on degraded land, to increase the feasibility of limiting global warming to less than 2 or preferably 1.5 degrees C. Some peer-reviewed sequestration estimates are of a similar order of magnitude to other food systems mitigation options over a 10-20 years period, such as reducing food loss and waste by 15% or aligning diets with current health related dietary-recommendations. However, caution should be applied to such comparisons since mitigation estimates are associated with large uncertainties and will ultimately depend on the economic cost-benefit relation, feasibility of implementation and time frame considered.