Multiple agroecological practices use and climate change mitigation. A review

Agriculture is increasingly affected by climate change but is also a significant contributor of greenhouse gas (GHG) emissions. This global study aims to find evidence on the impact of agroecological practices on climate change mitigation, namely GHG emissions (CO₂, N₂O, and CH₄) and carbon sequestration. We used a rapid review methodology, screening more than 16,000 publications to retrieve evidence on the implementation of multiple agroecological practices on climate mitigation, for which a knowledge gap exists. We addressed the positive, negative, and inconclusive effects of agroecological multi-practices on climate change mitigation as compared to conventional counterparts. The results of the review indicate that (1) multiple agroecological practices are often associated with statistically significant positive climate change mitigation outcomes across the broad range of evaluated metrics (46% positive, 13% negative, <1% inconclusive outcomes). For all four metric types, there were always more positive than negative outcomes. (2) Within GHG emissions, the highest share of positive outcomes was for CO₂ with 0.69 followed by N₂O (0.67). For carbon stock, positive significant results dominated with 70%, whereas significant negative outcomes were reported for only 7%. (3) For 28% of all metrics, no statistical tests were used or not applied for the combination of practices, resulting in 57% positive, 31% negative, and 11% inconclusive outcomes. (4) A general trend with more positive outcomes with increasing number of agroecological practices was found for carbon sequestration but not for GHG emissions metrics. (5) The majority of studies focused on arable systems, where many metrics showed positive outcomes in particular for carbon sequestration; however, a considerable number of negative outcomes were found for CO₂ and CH₄ emissions, particularly in rice. Although the results of this review show more positive outcomes with multiple agroecological practices, there are trade-offs, e.g., between carbon sequestration (positive effect) and GHG emissions (negative effect).