The Northern Ireland economy is heavily dependent on services. The top industries (ranked by percent of gross value added in 2006) are real estate, renting and business activities (16%); manufacturing (15%); wholesale and retail trade (13%); and a large portion of the economy (30%) devoted to providing public services: public administration and defense; health and social work; education; and other services. Although agriculture represents less than 2% of total GVA it has strong links to food and drink processing which comprises a third of manufacturing output (NISRA 2009) and is consistently above other regions in the UK. The majority of energy consumed in Northern Ireland comes from imported fossil fuels (mostly petroleum, with some coal and gas), with less than one percent from renewable sources and waste in 2005 (BERR 2008).
Greenhouse gases (GHGs) are considered a major contributor to climate change, causing public interest in tracking and controlling the level of emissions. The GHG emission inventory for the United Kingdom (Jackson, Li et al. 2008) includes carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), Perfluorocarbons (PFCs), and sulphur hexafluoride (SF6). Aggregated and expressed in millions of tons of carbon dioxide (MtCO2) equivalent, energy1 is responsible for a large majority of emissions in Northern Ireland (73%) due to the use of fossil fuels, with the second largest share of emissions (21%) attributed to agriculture (mainly N2Ofrom fertilizers and soils, as well as CH4 from livestock). The agri-food contribution to GHG emissions in Northern Ireland appears to be significantly higher than other regions in the UK.