Exploring the Kuznets hypothesis in the United Kingdom’s agricultural sector

This study examines the relationship between agricultural greenhouse gas (GHG) emissions (nitrous oxide (N₂O) and methane (CH₄)) and sectoral development in the United Kingdom (UK) using an Environmental Kuznets Curve (EKC)–motivated framework. Annual data from 1990 to 2022 were analysed using autoregressive distributed lag error‑correction models (ARDL‑ECM). The analysis incorporated agricultural Gross Value Added (GVA), Total Factor Productivity (TFP), and the Agricultural Trade Balance (ATB). Descriptive trends show that livestock is the dominant source of agricultural GHG emissions and that both N₂O and CH₄ emissions have declined over the study period while agricultural GVA and productivity (TFP) have grown. However, despite visual indications of nonlinear patterns, analysis, including long‑run marginal effects, the Lind–Mehlum (SLM) test, and flexible Generalized Additive Models (GAMs), find no statistical evidence supporting an inverted‑U EKC for either N₂O or CH₄. N₂O emissions remain positively associated with agricultural GVA across the income range, while CH₄ shows weak and statistically uncertain negative income elasticities. Dynamic impulse‑response and variance‑decomposition results further highlight the central role of productivity and technological progress in reducing emissions over time, with TFP emerging as the dominant long‑run driver of N₂O variation and agricultural GVA explaining the largest share of CH₄ forecast variance. Overall, the findings indicate that emissions reductions in UK agriculture have been driven not by autonomous income‑based EKC mechanisms but by structural change, productivity gains, and policy interventions. These results underscore the need for targeted, emission‑specific mitigation strategies rather than reliance on income‑led environmental transitions within the agricultural sector.