A scoping review of UK evidence for the impacts of regenerative agriculture practices on net greenhouse gas balances

CONTEXT ‘Regenerative agriculture’ (RA) is being advocated as a means of mitigating climate change. Global-scale meta-analysis and evidence reviews on the impacts of individual RA practices suggest some climate benefits. However, RA's climate impacts appear to be highly site specific and dependent on local climate and soil conditions. Evidence from one region may therefore not provide a robust basis for informing policy or practice elsewhere. OBJECTIVE Despite the momentum behind RA, we are not aware of any peer-reviewed evidence synthesis that assesses whether the UK evidence base for RA's purported climate impacts can robustly guide policy and practice. We use a scoping review of the peer-reviewed empirical literature in the UK to address this knowledge gap. METHODS We use the PRISMA extension for scoping reviews (PRISMA-ScR). We use a five-step framework to structure the review: identifying the research question; identifying relevant studies; study selection; extracting and charting the data; and collating, summarizing, and reporting the results. We consider empirical evidence that measures the impact of RA practices on components of net greenhouse gas balances. RESULTS AND CONCLUSIONS The empirical evidence for the impacts of RA practices on net greenhouse gas balances in the UK is inadequate for robustly informing policy or practice due to five main limitations. Firstly, data are only available for 30 of 90 RA practices we identified, with entire areas of RA activity having little-to-no empirical evidence. Secondly, 64% of studies were from in England, meaning that data available to support decisions for the specific farming systems, soil types, and climates in Scotland, Wales and Northern Ireland is further limited. Thirdly, most practices for which we found some empirical evidence are supported by very few studies. Fourthly, comprehensive assessment of the net greenhouse gas balances is precluded because data are only available for a limited range of greenhouse gas or carbon responses. Finally, only 21% of the studies considered yields alongside net greenhouse gas balances reducing stakeholders' ability to assess overall impacts. SIGNIFICANCE Our review found remarkably little evidence for the impacts of RA practices on net greenhouse gas balances in the UK, given the considerable interest from a range of actors. It is clear that considerable evidence needs to be generated rapidly to ensure that the most effective practices, either RA or other approaches, are promoted in appropriate locations.