A surge in pig and poultry farming in Northern Ireland has built a multimillion-pound industry, feeding British consumers chicken and pork. But it is creating a climate and pollution headache for politicians. After a decade of growth, the country has a poultry population of 25 million and pig production has risen to almost 1.5 million, with most of the meat exported to Great Britain. The figures show Northern Ireland has no shortage of ingredients for sausages in the midst of a bitter row between the EU and the UK over a looming ban on chilled meats traded from Great Britain into the region. But the country is struggling to dispose of its animal waste sustainably – and may need to export more than a third of it. Rising phosphate and nitrate levels are also threatening the country’s waterways and pushing the UK over international ammonia limits. Advisory bodies have told politicians that as much as 35% of animal waste may need to be exported to improve water and soil quality in the region, and that “agricultural activities remain a significant and increasing pressure on water quality” in Northern Ireland. Only one lake out of 21 in Northern Ireland is considered of good status under the EU’s water framework directive, legislation intended to improve river water quality. The devolved administration’s first climate bill moved to its second reading last month, setting a 2045 net zero carbon target for Northern Ireland. Farming groups claim the target could wipe out half of the country’s livestock farmers if it was enforced. A quarter of Northern Ireland’s poultry litter is exported, but there are no figures on the full extent of animal waste exports. Slurry and concentrated solid manure produced by intensive pig and poultry operations is being deposited over the Irish border as far as Wexford, more than 150 miles south. Part of the remainder is shipped to incinerators in Great Britain, including sites at Norfolk and Fife. Material transported to the Irish Republic is largely used as fertiliser or goes to anaerobic digester plants for biofuel. Cross-border pollution from Northern Ireland’s excess waste disposal has triggered legal action, with cases being prepared by Friends of the Earth and Ireland’s national trust body, An Taisce, which owns land straddling the frontier between Monaghan and Tyrone. The Green party says 98% of special areas of conservation in Northern Ireland exceed critical loads of nitrogen, with some by up to 300% or more. James Orr, Friends of the Earth Northern Ireland director, says transboundary pollution is the result of years of regulatory inaction either side of the border. He argues that intensive farming practices have led to: “Air pollution, chronic water pollution and also habitat degradation through the ripping out of natural and semi-natural habitats for intensification.” “We’re a centre for agribusiness in Northern Ireland, which means we’re now saturated with excrement,” said Orr. “And not just ourselves, but our neighbours, too, are paying the price.” The growth in intensive pig and poultry farming in the country continues, with planning decisions awaited on mega units set to house tens of thousands of pigs and chickens in Newtownabbey, Fermanagh and Limavady – poised to be some of the UK’s largest intensive livestock farms. The number of intensive poultry farms (with 40,000 or more birds) granted planning permission in Northern Ireland rose from 141 in 2011 to 245 in 2017, according to figures obtained under the Freedom of Information Act by the Bureau of Investigative Journalism. During this period, Moy Park, Northern Ireland’s largest company and Europe’s biggest poultry processor, encouraged the construction of hundreds of new poultry houses at Northern Irish farms. Poultry numbers in Northern Ireland increased by 27% between 2012 and 2020 to almost 25 million. Between 2006 and 2020, the slaughter of home-produced pigs more than doubled in the region – from 717,172 to 1,444,150 – while its breeding herd grew by 31% between 2006 and 2019. Meanwhile, between 2011 and 2018, Northern Ireland’s pigmeat export sales almost doubled – from £54.8m to £106.2m – as total agri-food exports rose by 77%. About 80% of the region’s meat is exported, with Great Britain its biggest market by some way, accounting for almost two-thirds of agri-food product exports in 2015. Mark Sutton, an environmental physicist at the Centre for Ecology and Hydrology, says that, while recognising agriculture represents a large part of the Northern Irish economy, there is a pressing need to meet targets on nitrogen emissions, of which ammonia is one compound – with much of the UK’s climate focus ahead of Cop26 centring on carbon emissions. Citing damage to nitrogen-sensitive sphagnum moss and peat bogs – which act as carbon sinks – caused by the waste surplus, Sutton argues that measures as straightforward as using newer slurry-spreading machinery and more efficient storage of manure fertiliser could help reduce Northern Ireland’s emissions significantly. “We estimate that something like 80% of [all] the nitrogen inputs that are going into agriculture get wasted,” Sutton said. “If we want to meet our net zero targets, we need to take action on nitrogen. One of the problems is how fragmented its by-products are – you have ammonia, nitrates in the water and nitrous oxide, a greenhouse gas hundreds of times as potent as CO2, coming out of the soils,” he said. Fermanagh and Omagh district councillor Chris McCaffrey said farmers were trying to diversify by “copying this industrial model, which brings massive environmental and public health risks, as well as risks for animal welfare. “We have very low topsoil here in Fermanagh – only a couple of centimetres. So it’s not very long before ammonia and other pollutants get into the water table.” An application for a new 1,000-pig unit in his ward, on the edge of the Derrylin townland, was rejected last year following widespread community opposition. Northern Ireland’s Department for Agriculture, Environment and Rural Affairs (Daera) said it has “developed an ammonia strategy, which will be published for consultation soon. This strategy outlines a comprehensive approach to ammonia reduction and the protection and restoration of habitats.” “Daera has already taken action to address ammonia in Northern Ireland, including funding a wide-ranging ammonia research programme, publishing a code of good agricultural practice for the reduction of ammonia emissions and supporting farmers financially to invest in ammonia reduction technologies such as low emissions slurry spreading equipment, which reduces the ammonia and water quality impacts of slurry spreading through schemes such as the farm business improvement scheme.” Sign up for the Animals farmed monthly update to get a roundup of the best farming and food stories across the world and keep up with our investigations. You can send us your stories and thoughts at animalsfarmed@theguardian.com