Estimating the UK’s greenhouse gas emissions

 

CH4_average_emissions_map_hires
UK methane emissions (log10(g/s/gridcell) inferred from four atmospheric monitoring stations in the UK and Ireland.

In parallel with efforts to create a detailed bottom-up inventory (National Atmospheric Emissions Inventory) for the major greenhouse gases, the UK ┬áhas funded four monitoring stations┬áto infer emissions for the purposes of verification. In our new study, available on Atmospheric Chemistry and Physics Discussions, we have used two years of data to estimate emissions of methane and nitrous oxide at high resolution in the UK and Ireland. In our study, we found that UK emissions of methane and nitrous oxide were largely over-estimated from the inventory. Because of the distinct spatial distributions of the major sources of methane (cattle from the West, landfills from the East), we found that the largest decrease from the inventory occurred in the cattle grazing regions of the country. We also found a signifiant seasonal cycle in nitrous oxide emissions, due to seasonality in fertilizer usage in the country. Emissions maximize in the late spring/summer. High resolution “top-down” studies, such as this one, can be used to identify discrepancies with the inventory, with the ultimate aim of improving inventories