The impact of ammonia emissions from agriculture on biodiversity An evidence synthesis Susan Guthrie, Sarah Giles, Fay Dunkerley, Hadeel Tabaqchali, Amelia Harshfield, Becky Ioppolo, and Catriona Manville For more information on this publication, visit www.rand.org/t/RR2695 Published by the RAND Corporation, Santa Monica, Calif., and Cambridge, UK R® is a registered trademark. RAND Europe is a not-for-profit research organisation that helps to improve policy and decision making through research and analysis. RAND’s publications do not necessarily reflect the opinions of its research clients and sponsors. (www.randeurope.org) Support RAND Make a tax-deductible charitable contribution at www.rand.org/giving/contribute © Copyright 2018 The Royal Society The Royal Society is a self-governing Fellowship of many of the world’s most distinguished scientists drawn from all areas of science, engineering, and medicine. The Society’s fundamental purpose, as it has been since its foundation in 1660, is to recognise, promote, and support excellence in science and to encourage the development and use of science for the benefit of humanity. (www.royalsociety.org) The text of this work is licensed under the terms of the Creative Commons Attribution License which permits unrestricted use, provided the original author and source are credited. The license is available at: creativecommons.org/licenses/by/4.0 Images are not covered by this license. III Preface This report provides a synthesis of the The Royal Society is the independent scientific existing evidence on the impacts of ammonia academy of the UK and the Commonwealth, emissions from agriculture on biodiversity and dedicated to promoting excellence in science. the possible interventions to reduce emission RAND Europe is a not-for-profit policy research levels. The review was conducted in 2018 by organisation that helps to improve policy and RAND Europe, working in collaboration with decision making through research and analysis. the Royal Society. The study was funded by the Royal Society. The document should be For further information about RAND Europe of use to policymakers and others interested and this document, please contact: in understanding the current status of the Susan Guthrie, Research Leader evidence around ammonia emissions, their RAND Europe, Westbrook Centre, Milton Road impact on biodiversity, potential interventions Cambridge CB4 1YG, UK to reduce emissions and their effectiveness, Tel: +44 1223 353329 and costing of both harms of emissions and E-mail: [email protected] interventions to reduce emissions. i Summary As levels of other air pollutants have declined, and out-compete species which are more ammonia emissions in the UK have been rising sensitive, smaller or rarer. Ammonia pollution since 2013, with significant implications for also impacts species composition through soil biodiversity and human health. The agricultural acidification, direct toxic damage to leaves and sector is the biggest contributor to ammonia by altering the susceptibility of plants to frost, pollution, producing 82 per cent of all UK drought and pathogens (including insect pests ammonia emissions in 2016. The aim of this and invasive species). At its most serious, if study is to provide an overview of the existing changes in species composition and extinctions evidence in three main areas: are large, it may be that remaining vegetation and other species no longer fit the criteria for • The impacts of ammonia emissions from that habitat type, and certain sensitive and agriculture on biodiversity in the UK. iconic habitats may be lost. • The interventions available to reduce ammonia emissions from agriculture and Certain species and habitats are particularly their effectiveness. susceptible to ammonia pollution. Bog and peatland habitats are made up of sensitive • The costs of the interventions, and how lichen and mosses which can be damaged these compare to the costs of inaction by even low concentrations of ammonia. on ammonia emissions, both in terms of Grasslands, heathlands and forests are also impacts on biodiversity and wider impacts vulnerable. However, much of the wider (e.g. on human health). evidence on biodiversity impacts relates to all nitrogen pollution, rather than just ammonia. Impact of ammonia on biodiversity There is far less evidence on the impact of Ammonia itself and the nitrogen deposition ammonia, and nitrogen more generally, on resulting from ammonia emissions negatively animal species and the wider ecosystem. affect biodiversity. Ammonia is one of the However, animal species depend on plants as a main sources of nitrogen pollution, alongside food source; therefore herbivorous animals are nitrogen oxides. A major effect of ammonia susceptible to the effects of ammonia pollution. pollution on biodiversity is the impact of nitrogen There is a negative correlation between accumulation on plant species diversity and flower-visiting insects, such as bees and composition within affected habitats. Common, butterflies, and nitrogen pollution. Ammonia fast-growing species adapted to high nutrient affects freshwater ecosystems through direct availability thrive in a nitrogen-rich environment agricultural run-off leading to eutrophication ii The impact of ammonia emissions from agriculture on biodiversity (accumulation of nutrients, leading to algal be considered cost-effective, which would growth and oxygen depletion) and also has include the majority of interventions. However, toxic effects on aquatic animals that often have the whole ammonia lifecycle needs to be thin and permeable skin surfaces. taken into account. If emissions are reduced immediately after manure production (e.g. Quantifying the economic impact of ammonia through collection), but then not reduced in emissions on biodiversity is challenging and later stages (e.g. in storage or in spreading), the methods used are subject to debate. then the emissions benefits at earlier stages Available estimates suggest that loss of are negated. Therefore, interventions need to biodiversity due to ammonia emissions could be used in combination, spanning the whole have impacts in the UK which can be valued, lifecycle of manure production, storage and conservatively, at between £0.20 and £4 application. This also highlights the benefits per kg of ammonia. Combining this with the of feed-based approaches which reduce the monetised health impacts, our conservative amount of ammonia produced in manure in the estimate of the total costs from both health first place. It is also important to consider the and biodiversity impacts of ammonia in the UK interplay of ammonia emissions with those of is £2.50 per kg of ammonia (though the range other polluting gases, which might be negatively of possible values is from £2 to £56 per kg). affected by some interventions, or by ammonia This conservative estimate, combined with reductions generally. For example, excess projected emission data, suggests that if no nitrogen, whilst reducing species richness, can action is taken to reduce ammonia emissions, increase the volume of plant matter overall, the negative impacts on the UK in 2020 could which has benefits for carbon sequestration. be equivalent to costs of over £700m per year. However, there are significant uncertainties From a policy perspective, a mix of regulation, in these values. The range of possible costs, incentives and education are likely to be based on the estimates in the literature and necessary to support the implementation of best available projections for emissions, are interventions. Evidence from the Netherlands between £580m and £16.5bn per year. and Denmark suggests that for interventions with a high level of acceptability to the Reducing ammonia emissions agricultural sector, regulatory approaches can be introduced fairly quickly to support compliance. Ammonia emissions can be reduced by Where there are high upfront costs for farms, or managing the production, storage and a lower level of acceptability or knowledge, there spreading of manure. Some of the most may be more need for incentives and education, established ways to do this are summarised alongside voluntary actions in the first instance, in Table 1. Figure 1 provides an overview before regulation can be effectively introduced. of the cost-effectiveness, acceptability and It may also be that different approaches are strength of evidence for a range of specific needed across different farm types or sizes. interventions. Based on our estimates above, Wider education and awareness-raising may the impacts of ammonia can be conservatively also be needed to help build understanding of costed at £2.50 per kg, which is equivalent the importance and costs of ammonia reduction to £1 of damage being caused by every amongst the public and in the retail sector, so 0.4kg of ammonia emitted. On this basis, any that the full cost of these measures are not intervention which exceeds this threshold placed solely on the agricultural sector and/or – to the right of the line in Figure 1 – could government subsidies. iii Table 1. Summary of categories of interventions to reduce ammonia emissions Reduction Implementation cost Method Description in ammonia Limitations (£/kg of ammonia) emissions Higher feeding costs to farmers and potential for Reducing the amount Livestock imbalanced nitrogen levels of excess protein in 10% to 60% -2.3 to 2.3 feed in the farm as the full use livestock diets of grass production is not guaranteed Designing animal High investment costs to Animal