GHG emissions and carbon sequestration in the apple production in the context of Net Zero

Achieving global net zero GHG emissions requires both enhancing sinks and reducing emissions. This study reviews LCA and wider literature on apple production globally to identify ranges of emissions and carbon sequestration in orchards, to inform pathways of transitioning apple production systems to net zero.
We reviewed a total of 84 published papers investigating the contribution of apple production to environmental impacts globally. 38 of these papers were selected for further investigation based on availability of transparent data. To enable the comparison on the same terms from different apple production practices in different geographic and climatic conditions, we harmonised the inventory data across available datasets from reviewed LCA studies. In parallel, we conducted a focused review of orchard carbon sequestration to provide ranges of carbon sequestration in apple orchards. Finally, we combine the above steps together and discuss pathways to net zero GHG emission of apple production.
Our review reveals a large range of GHG emissions from apple production reported by different studies, ranging between 1 and 67 tCO2-eq/ha/yr. In comparison, we found that sequestration by above ground vegetation in apple orchards could be in the range 29 to 79 tCO2/ha/year. The balance between GHG emissions and sequestration in orchards depends on understanding and reducing emissions, while enhancing carbon sequestration. To help this decision, our review identified energy consumption (diesel in agricultural machinery, electricity for irrigation) and fertiliser application as key GHG emission drivers, irrespective of location of apple production. However we identified large differences in fertilisation and energy consumption practices, influenced by different cultivation practices and local conditions, which we discuss further in order to derive key recommendations for emission reduction in apple orchards. In terms of carbon sequestration in orchards, we identified a key research gap,
i.e. usually carbon sequestration is not included within the boundaries of LCA studies. In order to provide an estimate of carbon sequestration in apple orchards we used data from the 31 reviewed LCA studies and reviewed other 4 literature. However, joining together the two sources of data may lead to further uncertainty. Therefore we recommend further research into understanding ways of carbon sequestration in orchards and their potential of storing carbon. This should be connected to estimating emissions in the orchard, so the two measures do not cancel out each other.