Figures
Abstract
Agriculture dominates the planet. Yet it has many environmental costs that are unsustainable, especially as global food demand rises. Here, we evaluate ways in which different parts of the world are succeeding in their attempts to resolve conflict between agriculture and wild nature. We envision that coordinated global action in conserving land most sensitive to agricultural activities and policies that internalise the environmental costs of agriculture are needed to deliver a more sustainable future.
Citation: Tanentzap AJ, Lamb A, Walker S, Farmer A (2015) Resolving Conflicts between Agriculture and the Natural Environment. PLoS Biol 13(9): e1002242. https://doi.org/10.1371/journal.pbio.1002242
Published: September 9, 2015
Copyright: © 2015 Tanentzap et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Funding: This essay came out of a symposium supported by the Natural Environment Research Council grant NE/M005968/1. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
Abbreviations: AES, agri-environment schemes; CRP, Conservation Reserve Program; GHG, greenhouse gas; IUCN, International Union for Conservation of Nature; NRA, nominal rate of assistance; OECD, Organisation for Economic Cooperation and Development; PS, producer support; PSE, producer support estimate; RMA, resource management act; VOP, value of production; WTO, World Trade Organization
Introduction
Agriculture is the most dominant land use on Earth and will remain so as the world’s population and global food demand rise [1] (Fig 1). This poses a fundamental challenge to the natural environment, which requires access to many of the same resources as agricultural producers and is harmed by agriculture’s external impacts [2,3]. Using land resources for agriculture prioritises crop and livestock production over the many other benefits that natural ecosystems provide and that agriculture displaces, including biodiversity, carbon storage, and water purification [4]. Governments also heavily support agricultural production in ways that are often bad for the environment, such as rewarding output or lowering input prices [5,6]. Very little is spent on actively mitigating the environmental impacts (Fig 1).
We distinguished between policies aiming to achieve specific environmental objectives beyond those required by regulation (purple segments) and all other types of support irrespective of their influence on farm production or income (orange segments), e.g., market price support, monetary transfers based on output, input subsidies. Sizes of symbols were scaled to VoP in hundreds of millions of United States dollars. Data are from the most recent year available (2008–2013) and described in S1 Text. Green and brown shading in the background is the percent of cropland and pasture at 5’ resolution in the year 2000 [7]. Financial support data were preferentially sourced from the Organisation for Economic Cooperation and Development (OECD) (n = 21 countries), supplemented from the World Trade Organization (WTO) where possible for additional countries (n = 12). Data used to make this figure are provided in S1 Data.
Here, we summarise how agriculture impacts the natural environment and then scrutinise the success of government agricultural policies that we believe offer the most promise for safeguarding nature while feeding a growing human population. We use economic and political theory to help explain why some measures are more prone to succeed than others, recognising that scientific understanding of a problem does not mean it will be solved [8]. Throughout, we touch upon examples from centres of agricultural production.
A Cultivated Planet
Agriculture’s demand for land drives conversion of natural habitats, and this is arguably its largest environmental cost. Approximately 40% of ice-free land (4,300 million ha) is already covered by crops or used to raise livestock [7], and an additional 2.7–4.9 million ha of cropland annually, the size of a small European nation, may be required to feed the world’s population by 2030 [1,9]. Conversion of land for agriculture is estimated to account for 80% of global deforestation [10], and ca. 53% of terrestrial species assessed as threatened by the International Union for Conservation of Nature (IUCN) [11] are negatively impacted by agriculture (Fig 2). Land conversion also reduces the size of the terrestrial carbon sink. Global simulation models predict that 24% and 10% less carbon is stored in vegetation and soil, respectively, than if present-day landscapes retained their natural vegetation [12].
We counted the total number of species classified as either critically endangered, endangered, or vulnerable by the IUCN Red List in different taxonomic units and the number that were assessed to be threatened by at least one agricultural activity [11]. Agricultural activities were annual and perennial nontimber crops, wood and pulp plantations, livestock farming and ranching, logging and wood harvesting, abstracting of surface water (agricultural use), abstraction of ground water (agricultural use), and agricultural and forestry effluents. Many other species may become threatened with agricultural expansion (S2 Fig).
Agriculture also contributes more to other forms of environmental degradation than any other economic sector. Between 30%–35% of global greenhouse gas (GHG) emissions come from agriculture [3], and crop irrigation accounts for 70% of the world’s freshwater withdrawals [13]. The use of synthetic nitrogen fertiliser has increased nearly 21-fold since 1950, and more nitrogen is now added to agricultural soils than from natural processes [14]. Virtually all human-derived nitrogen is lost to the atmosphere or receiving waters [14,15]. This eutrophication suffocates aquatic ecosystems [16]. Phosphorus from fertiliser and livestock manure [14,17], pesticides [18–20], and nanoparticles [21,22] are also exacerbating environmental pollution. Additionally, poor agricultural management causes soil degradation, reducing agricultural productivity and creating further demand for nutrients, water, and land conversion [23,24].
Solutions for limiting agriculture’s environmental costs are increasingly well understood. These include reducing land clearance by improving yields of existing crops, minimizing excess nutrient and water use, and shifting production from livestock towards crops [3]. Implementing these practices for only a handful of commodities in a subset of the world can have a large environmental benefit [25]. The success of these practices, however, depends on how well policy puts them into practice.
Challenges to Limiting Agriculture’s Environmental Costs
Designing and implementing policies to reduce agriculture’s environmental costs is difficult. Like other industries, farmers and the businesses reliant upon them, such as input suppliers, processors, and retailers, have a rational self-interest in maximising economic returns and oppose policies that threaten their viability [26,27]. In developed economies, this has historically allowed them to organise into focused lobby groups with considerable advantage over diffuse public interests seeking to safeguard the environment [28,29]. Governments rarely benefit from challenging agri-food lobbies over environmental issues that lack immediate returns for the public good. These lobbies reward government for less demanding environmental policies [30,31], and tailoring policies appropriate for the range of physical and social conditions that farms occupy is costly [26,27]. Concerns about foodborne illness (including genetically modified organisms), environmental impacts (e.g., pesticide use), and animal welfare have ceded some power in the policy arena of developed countries from producers to consumers [32], and increasingly to large retailers, but existing governance structures remain highly susceptible to farmer interests despite spatiotemporal variation in power relations [29]. For example, corporate lobbying efforts in the agricultural sector were deemed effective by 52% of respondents in a 2013 survey of nearly 600 European Union (EU) decision makers, and >80% effectiveness was reported in Denmark, Latvia, and the United Kingdom [33]. Policymakers therefore face major challenges in aligning the private interests of the agri-food sector with public interest in environmental goods across the diversity and extent of farm entities.
In addition to political challenges, measures that do succeed in reducing the environmental harms of agriculture in one place can perversely increase them elsewhere. This is because, in a global market, local policies or technologies that cause agricultural production to carry a greater opportunity cost than using land for environmental goods will displace production to regions where these costs are lower [34]. For example, regulations limiting fertilisers can reduce local water pollution and GHG emissions. But because such measures may reduce yields (i.e., tonnage of production per unit area), food demand will be met elsewhere, leading to intensification and land clearance that potentially creates a net environmental loss [35]. Incentivising low-intensity systems, seen as beneficial to biodiversity conservation in regions such as Europe, may similarly limit production and displace environmental impacts while also lacking the full benefits of natural ecosystems [36]. Efforts to limit the environmental costs of agriculture must therefore consider the environmental impacts beyond farm boundaries as well as the consequences for food production.
Potential Resolutions to the Agriculture–Nature Conflict
Agricultural policy with explicit environmental objectives is generally organized around three approaches (Table 1 and expanded upon in S1 Table; see Box 1 for an exception):
- regulations, such as limits on pesticide use or abstracting water, which can be enforced through penalties and conditions placed on financial support to farmers;
- community-based approaches, which support farmers and local stakeholders to work collectively in addressing environmental impacts; and
- economic instruments, which pay farmers directly or create markets for adopting practices that minimise environmental impacts and provide noncommodity outputs beyond those required by existing regulation; tariffs can also be used to internalise environmental costs.
Box 1. Abandoning the Agricultural Sector to Market Forces
New Zealand radically altered its agricultural policy in 1984 to embrace minimal government intervention. It now relies exclusively on regulation to minimise the environmental impacts of agriculture while providing among the least support to domestic producers out of all developed countries (ca. 0.5% of the value of production; S1 Text). Consequently, the natural environment has been left vulnerable to the pressures of market forces, which are rapidly accelerating production and land conversion with increasing demand for dairy products in particular. The rate of conversion of indigenous grassland to exotic pasture in the South Island has increased by 67% from the period between 1990–2001 to 2001–2008 [52], and New Zealand leads the world in livestock emissions per capita, exceeding the global total across developed countries by more than 13-fold [53].
The nonprescriptive Resource Management Act (RMA) is the primary national legislation intended to oversee natural and physical resources, with land regulation devolved to elected district councils. Although the RMA tasks councils with “maintaining” biodiversity in balance with resource development, they generally expedite the latter. Fewer than 5% of agricultural sector consents requiring biodiversity or ecosystem services maintenance were recently found to comply with conditions [54]. Limited resources are often blamed for poor enforcement, but political interference also occurs [55]. Other regulations, such as the Wildlife Act and Native Plant Protection Act, are rarely invoked, and the latter does not apply to landowners [55].
New Zealand also has a dedicated judicial system to contest decisions made under the RMA. While this system has delivered several notable “wins” for the environment (e.g., [56]), many local actions escape scrutiny. In practice, biodiversity protection by rural landowners occurs mainly on small, voluntary, set-asides of residual unproductive land (known as covenants) and through patchy predator-trapping and stock fencing activities, supported by limited local and national funds. It appears that the laissez-faire approach to the agricultural sector does little to safeguard the environment.
Farmers will be motivated to accept one or more of these approaches where they incur small socioeconomic costs relative to the benefits that they receive from achieving environmental objectives [37,38]. Eliminating financial support for farmers to maximise agricultural production is important in helping to reduce the socioeconomic costs of adopting environmental practices. Reforms in developed economies since the 1980s are now supporting producer incomes more through direct payments than by subsidising production or protecting domestic prices [2,39] (Box 2).
Even with farmer acceptance, success of any policy approach will ultimately depend on whether farmers maintain or boost yields on existing agricultural lands rather than convert new natural lands to production. Halting local land conversion can be achieved with strict enforced regulations (Table 1), but in a globalized market, changes in the local supply of a given cash crop will lead to changes in demand and supply in other distant locations [59]. Trends in cereal production in 19 countries between 1990 and 2005 clearly show this link between local actions and global consequences. These countries managed to boost cereal yields on existing lands while removing cropland from production, but without fully meeting local demand. Per capita cereal imports consequently increased by 12-fold in these countries compared with those lacking land retirement policies [60], clearly suggesting that production was displaced elsewhere. Where subsistence agriculture is important, limiting its local production may similarly boost reliance on cash crops produced abroad [61]. National governments implementing any of the three main policy approaches need to begin working in a coordinated way to combat land use displacement.
Box 2. Environmental Harms of Agricultural Price Support
Price support policies, such as import tariffs or minimum commodity prices, encourage overproduction in the absence of supply management. This strains natural resources and makes marginal land artificially profitable [57]. In the US, the federal government historically managed the dairy industry by guaranteeing to purchase milk if its market price fell below a set value. Modelling revealed that this would drive abandonment and reversion to natural forest across thousands of hectares of land in the state of Wisconsin if milk prices were decreased by only 5%–15%, with millions saved in water treatment and government expenditure [58]. The US has now adopted a strategy of paying producers should their margins fall beneath national averages, likely with similar environmental consequences.
Finding the Right Mixture of Solutions
Maintaining the status quo with agricultural policy is unsustainable for the environment [3,35,62]. On their own, regulations and community approaches will offer little help if damaging the environment remains financially lucrative because the associated penalties are trivial, governments continue to subsidise production (Fig 1, S1 Fig), and farmers are not accountable for the environmental costs of their actions [63–65] (Box 3). Economic instruments, such as payments for public goods, are also contentious, especially for biodiversity conservation [66–68]. Positive outcomes often arise only from certain actions, such as enhancing specific food resources or nesting habitat [69], and catch-all interventions may avoid targeting rare species [70,71]. Removing production subsidies and making farmers financially responsible for their environmental impacts, such as with markets for public goods, can help local outcomes but must avoid curbing intensification because this will encourage land conversion elsewhere to meet demand for food [35].
Box 3. Balancing Large-Scale Incentives for the Rural Poor with Strict Penalties for Agri-business
China—the world’s largest agricultural producer—offers a stark contrast in government policy to that implemented by New Zealand described in Box 2. The country’s economy is heavily controlled by centralised government and relatively free from the political influence wielded by farmers lobbies. Government can therefore act largely in its own self-interest, which may align more often with the public good. This has allowed the Chinese government to implement environmental policies on scales that would be virtually impossible elsewhere in the world. The Grain to Green Project is one example, having converted nearly 9.1 million hectares of cropland into forest whilst incentivising farmers to participate with grain and cash subsidies [72]. This permanent land retirement scheme has reduced soil erosion and increased carbon sequestration at landscape scales [73]. China is also adopting a stricter approach to large industrial agriculture. In 2014, the country’s top legislature revised the national environmental protection law for the first time in 25 years. The revisions included harsher penalties to deter companies from accepting fines rather than investing in pollution control [74]. Whether enforcement follow suits remains to be seen.
Ruhl [26] argued that successful agricultural policies will target large industrial operations that can be readily regulated while incentivising changes in production practices by small farmers without compromising their livelihoods. Recent developments in China are therefore promising, but the country’s agricultural sector still causes major environmental harm, including poor water quality in almost all rivers and lakes [75], and nearly 40% more GHG emissions per tonne of nitrogen fertiliser than in Europe [76]. Subsidies on inputs such as fertilisers and pesticides are largely to blame as they promote overuse. Fertilisers are estimated to be overused by 30%–60% [77], yet nearly CMY¥108,000 million (US$17,000 million) was spent in 2012 on just one scheme to help farmers purchase more of these inputs [78]. Removing harmful financial subsidies would help greatly in aligning the country’s agricultural and environmental aims.
We assert that conflict between agriculture and the environment will be best resolved by policies dedicating high-quality habitat towards nature conservation, while encouraging intensive production on existing farmland with stringent limits on environmental impacts [35,36,79–81]. Measures that make farmland itself more benign—so called “land-sharing” approaches—also deliver local environmental and social benefits [82,83], but can reduce agricultural yields and cause land conversion elsewhere, effectively displacing environmental burdens [80]. Intensifying production on existing farmland may thus be a better option because it avoids displacing impacts and can allow other land to be freed for nature conservation and restoration, with no net loss in agricultural production.
Our consideration of policy instruments approaches and the obstacles to their success (Table 1) suggests that our proposed resolution would practically entail a combination of punitive measures, such as taxes that reduce existing overuse of farm inputs [84], with positive incentives linked to measurable outcomes [49], such as for permanently removing land from production. Taxes on farm inputs can improve upon existing payments to limit input use because they do not explicitly cap nutrient, pesticide, and water use. Without input limits, some farmers may find it profitable to intensify existing production, despite the added taxes, while others might profit more from reducing resource consumption. Across the landscape, yields will be maintained, and potentially increased without additional land conversion. For example, water surcharges in Mexico are used to pay landowners to retain forested watersheds. Displaced land conversion from exploitation of communal properties and changing market pressures reduced the environmental benefits of this programme by only ca. 4% [85]. By enabling farms to respond differently to the same policy, input taxes carry an additional advantage over traditional regulations that hold all farmers to the same standard and ignore sectorial diversity [86]. An aligned but more audacious approach would be to replace taxes on income with taxes on environmental consumption. The idea is to shift from taxing the production of private wealth toward taxing the consumption of public environmental goods, thus promoting economic growth from sustainable use rather than depletion of natural capital. Brown et al. [55] have proposed that such a system would most heavily tax intensive land uses that generate the most negative environmental impacts, while areas of intact ecological function would entitle the owners to a rebate. This approach might encourage farmers to work intensively with the most productive land but set aside and restore less productive areas with net gains for the environment.
Evidence at national levels suggests that investments in land retirement and input-limiting schemes, consistent with our suggested policy approach, do deliver local environmental benefits. To illustrate this, we examined trends in two environmental responses, farmland bird populations and GHG emissions from synthetic fertilisers, across countries with similar agricultural patterns, i.e., dominated by livestock and arable crops (see S1 Text for methods). We calculated the annual, per hectare monetary investment in a specific environmental outcome beyond that required by regulation from a detailed inventory of government policies compiled by the OECD (annotated in S1 Data). As expected, because habitat loss is a major threat to farmland and grassland biota, we found that farmland birds benefited as more money was invested in retiring agricultural land (Fig 2). We also found that total emissions of N2O declined with increasing investment in reducing fertiliser use (Fig 3). While cursory in nature, these results suggest that targeted policies have the potential to deliver positive environmental outcomes.
Temporal trend in (A) farmland bird populations and (B) GHG emissions from synthetic fertiliser were calculated over time for each country using Kendall’s τ (see S1 Text for full methods). Investments in AES were scaled by the ratio of investments in AES relative to financial transfers to agricultural producers for all other purposes so as to account for the fact that environmental improvements can be offset by policies that maximise production. Values were then summed across 5-y periods with a pre-emptive 2-y lag for land retirement. Habitat quality will take at least one growing season to improve following land retirement and any changes in bird populations from improved breeding success will thus largely be measurable the following year, i.e., two years later [87,88]. Spearman’s rank correlation: ρ = 0.95, p = 0.005 and ρ = -0.93, p = 0.008 for (A) and (B), respectively. Points are responses in individual countries: AU = Australia [data available for (B) only], CA = Canada, EU (aggregated together), NO = Norway, CH = Switzerland, and US. Data used to make this figure are provided in S1 Data.
Measures delivering environmental benefits must also be coupled with mechanisms that promote intensification to avoid displacing production elsewhere, and they must do so with fewer external costs. Research suggests increased yields and better environmental practices are possible by improving nutrient and water management and breeding more efficient crops [3]. Reductions in food waste and human diets with less livestock and dairy consumption can also help meet rising food demands without increasing resource use [89,90]. Dietary change is, however, contentious. Governments may need to consider policies that tax livestock products and/or subsidize the development of livestock-free protein sources, e.g., [91], in order to dislodge entrenched norms.
Here, we have laid out a vision for limiting the environmental impacts of agriculture, yet at least two major challenges remain. First, winning political support for policy change remains a fundamental requirement to any of our proposed reforms. Ultimately, democratically elected governments, while not immune to the lobbying power of agribusiness, will generally respond to electoral pressures [31]. Electorates may express little desire for policy change if they are poorly informed, unmotivated, or misled by industry about limiting the environmental costs of agriculture. Second, implementation of our policy mixture will vary spatially. For example, successful land retirement depends on features of the surrounding landscape, such as habitat connectivity [92], and can reduce yields in regions where the most productive land also has the most valuable environmental assets. Nonetheless, improvements in the management of land resources in developing countries [93], new technologies that optimally allocate farm inputs to reduce overuse [94], advances in crop breeding [95], and tools for better conservation planning [96] give us hope that innovations exist for meeting the need for more sustainable and intensive agriculture.
Supporting Information
S1 Data. Investments in different agricultural policies used to generate Figs 1 and 3.
https://doi.org/10.1371/journal.pbio.1002242.s001
(XLSX)
S1 Fig. Proportion by which government policies increase gross returns to farmers as compared with the absence of government intervention.
Blue segments show the nominal rate of assistance (NRA) estimated in 2011 for 137 countries with agricultural sectors comprising >5% of gross domestic product [97]. NRA is equal to the difference in price of agricultural commodities that have been adjusted for changes in value associated with domestic policies, such as import tariffs or production subsidies, and the global undistorted price at the country border and expressed as fraction of the undistorted price [98]. It provides data on many more countries than the OECD producer support estimate and is also advantageous as it is expressed relative to the undistorted rather than distorted value [98]. Countries with NRA equal to zero (entirely white) provide no support to their agricultural sector, have a negative NRA (i.e., taxation), or are low to middle income (gross national income per capita of <$4,085 USD). Sizes of symbols are scaled to the total area under agricultural production.
https://doi.org/10.1371/journal.pbio.1002242.s002
(DOCX)
S2 Fig. Estimated numbers of near-threatened species negatively impacted by agriculture.
We counted the total number of species classified as either near-threatened or conservation-dependent in different taxonomic units and the number that were assessed to be threatened by at least one agricultural activity [11]. Agricultural activities were annual and perennial nontimber crops, wood and pulp plantations, livestock farming and ranching, logging and wood harvesting, abstracting of surface water (agricultural use), abstraction of ground water (agricultural use), and agricultural and forestry effluents.
https://doi.org/10.1371/journal.pbio.1002242.s003
(DOCX)
S3 Fig. Correspondence between the OECD Producer Support Estimate (PSE) database and WTO notifications.
Points are country-level estimates of: (A) support for AES; (B) total producer support (PS); and (C) value of production (VOP). Estimates are reported in a mixture of local currencies and US dollars, depending on country. n = 12 countries, except for (B), where the Ukraine is omitted because PS is negative due to the way in which market price support is calculated (see S1 Text).
https://doi.org/10.1371/journal.pbio.1002242.s004
(DOCX)
S1 Table. Pros and cons of measures used to mitigate conflict between agriculture and the environment.
We also predict the most likely consequences of these measures for food production (Δ yields), recognizing that some measures can vary substantially, such as if they produce environmental goods that promote yields (e.g., pollinators) and require compliance with conditions that also reduce yields (e.g., pesticide bans). Examples of where these measures are used are not intended to be exhaustive.
https://doi.org/10.1371/journal.pbio.1002242.s006
(DOCX)
References
- 1. Tilman D, Balzer C, Hill J, Befort BL (2011) Global food demand and the sustainable intensification of agriculture. Proc Natl Acad Sci USA 108: 20260–20264. pmid:22106295
- 2.
Warren J, Lawson C, Belcher K (2007) The agri-environment. Cambridge: Cambridge University Press. 232 p.
- 3. Foley JA, Ramankutty N, Brauman KA, Cassidy ES, Gerber JS, et al. (2011) Solutions for a cultivated planet. Nature 478: 337–342. pmid:21993620
- 4.
Millennium Ecosystem Assessment. Ecosystems and human well-being: synthesis. Washington, DC: World Resources Institute; 2005. 155 p.
- 5. James AN, Gaston KJ, Balmford A (1999) Balancing the Earth’s accounts. Nature 401: 323–324. pmid:16862091
- 6.
Myers N, Kent J (2001) Perverse subsidies: how tax dollars can undercut the environment and the economy. Washington, DC: Island Press. 277 p.
- 7. Ramankutty N, Evan AT, Monfreda C, Foley JA. (2008) Farming the planet: 1. Geographic distribution of global agricultural lands in the year 2000. Global Biogeochem Cycles 22: GB1003.
- 8. Lawton JH (2007) Ecology, politics and policy. J Appl Ecol 44: 465–474.
- 9. Lambin EF, Meyfroidt P (2011) Global land use change, economic globalization, and the looming land scarcity. Proc Natl Acad Sci USA 108: 3465–3472. pmid:21321211
- 10.
Kissinger G, Herold M, de Sy V (2012) Drivers of deforestation and forest degradation: a synthesis report for REDD+ policymakers. Lexeme Consulting, Vancouver. 46 p.
- 11.
International Union for Conservation of Nature [IUCN] (2014) The IUCN Red List of Threatened Species. Version 2014.3. http://www.iucnredlist.org via the Internet. Accessed 2015 March 14.
- 12. Bondeau A, Smith PC, Zaehle S, Schaphoff S, Lucht W, et al. (2007) Modelling the role of agriculture for the 20th century global terrestrial carbon balance. Glob Chang Biol 13: 679–706.
- 13.
Food and Agriculture Organization of the United Nations [FAO]. (2015) AQUASTAT database. Available: http://www.fao.org/nr/water/aquastat/data/ via the Internet. Accessed 14 March 2015.
- 14. Bouwman L, Goldewijk KK, Hoek KWVD, Beusen AHW, Van Vuuren DP, et al. (2013) Exploring global changes in nitrogen and phosphorus cycles in agriculture induced by livestock production over the 1900–2050 period. Proc Natl Acad Sci USA 110: 20882–20887. pmid:21576477
- 15. Galloway JN, Aber JD, Erisman JW, Seitzinger SP, Howarth RW, et al. (2003) The nitrogen cascade. BioScience 53: 341–356.
- 16. Diaz RJ, Rosenberg R (2008) Spreading dead zones and consequences for marine ecosystems. Science 321: 926–929. pmid:18703733
- 17. MacDonald GK, Bennett EM, Potter PA, Ramankutty N (2011) Agronomic phosphorus imbalances across the world’s croplands. Proc Natl Acad Sci USA 108: 3086–3091. pmid:21282605
- 18. Rohr JR, Schotthoefer AM, Raffel TR, Carrick HJ, Halstead N, et al. (2008) Agrochemicals increase trematode infections in a declining amphibian species. Nature 455: 1235–1239 pmid:18972018
- 19. Henry M, Béguin M, Requier F, Rollin O, Odoux J-F, et al. (2012) A common pesticide decreases foraging success and survival in honey bees. Science 336: 348–350. pmid:22461498
- 20. Hallmann CA, Foppen RPB, van Turnhout CAM, de Kroon H, Jongejans E (2014) Declines in insectivorous birds are associated with high neonicotinoid concentrations. Nature 511: 341–343. pmid:25030173
- 21. Priester JH, Ge Y, Mielke RE, Horst AM, Moritz SC, et al. (2012) Soybean susceptibility to manufactured nanomaterials with evidence for food quality and soil fertility interruption. Proc Natl Acad Sci USA 109: E2451–E2456. pmid:22908279
- 22. Santiago-Martín A, Constantin B, Guesdon G, Kagambega N, Raymond S, et al. (2015) Bioavailability of engineered nanoparticles in soil systems. J. Hazard. Toxic Radioact. Waste in press.
- 23. Pimentel D, Harvey C, Resosudarmo P, Sinclair K, Kurz D, et al (1995) Environmental and economic costs of soil erosion and conservation benefits. Science 267: 1117–1123. pmid:17789193
- 24. Lal R (1997) Degradation and resilience of soils. Phil Trans R Soc Lond B 352: 997–1010.
- 25. West PC, Gerber JS, Engstrom PM, Mueller ND, Brauman KA, Carlson KM, et al. (2014) Leverage points for improving global food security and the environment. Science 345: 325–328. pmid:25035492
- 26. Ruhl JB (2000) Farms, their environmental harms, and environmental law. Ecol Law Q 27: 263–349.
- 27. Walker S, Brower AL, Stephens RTT, Lee WG (2009) Why bartering biodiversity fails. Conserv Lett 2: 149–157.
- 28.
Olson M (1965) The logic of collective action. Cambridge: Harvard University Press. 208 p.
- 29. Daugbjerg C, Swinbank A (2012) An introduction to the “new” politics of agriculture and food. Policy Soc 31: 259–270.
- 30. Eskridge WN Jr (1988) Politics without romance: implications of public choice theory for statutory interpretation. Va Law Rev 74: 275–338.
- 31. Bellemare MF, Carnes N (2015) Why do members of congress support agricultural protection? Food Policy 50: 20–34.
- 32. Grant WP (2012) Can political science contribute to agricultural policy? Policy Soc 31: 271–279.
- 33.
Burson-Marsteller (2013) A guide to effective lobbying in Europe: the view of policy-makers. Available: http://burson-marsteller.nl/wp-content/uploads/2013/06/Lobbying-survey-Report.pdf. Accessed 1 June 2015.
- 34. Meyfroidt P, Rudel TK, Lambin EF (2010) Forest transitions, trade, and the global displacement of land use. Proc Natl Acad Sci USA 107: 20917–20922. pmid:21078977
- 35. Balmford A, Green R, Phalan B (2012) What conservationists need to know about farming. Proc Roy Soc B 279: 2714–2724.
- 36. Merckx T, Pereira HM (2015) Reshaping agri-environmental subsidies: From marginal farming to large-scale rewilding. Basic and Applied Ecology 16: 95–103.
- 37. Lastra-Bravo XB, Hubbard C, Garrod G, Tolón-Becerra A (2015) What drives farmers’ participation in EU agri-environmental schemes? Results from a qualitative meta-analysis. Environmental Science & Policy 54: 1–9.
- 38. Wilson GA, Hart K (2000) Financial imperative or conservation concern? EU farmers’ motivations for participation in voluntary agri-environmental schemes. Environment and Planning A 32: 2161–2185.
- 39.
Organisation for Economic Co-operation and Development [OECD] (2004) Agriculture and the environment: lessons learned from a decade of OECD work. Paris: OECD. 36 p.
- 40. Nepstad D, McGrath D, Stickler C, Alencar A, Azevedo A, et al. (2014) Slowing Amazon deforestation through public policy and interventions in beef and soy supply chains. Science 344: 1118–1123. pmid:24904156
- 41.
European Court of Auditors (2008) Is cross compliance an effective policy? Special report no 8/2008. Luxembourg: Office for Official Publications of the European Communities. 57 p.
- 42. Curtis A, Lockwood M (2000) Landcare and catchment management in Australia: lessons for state-sponsored community participation. Soc Nat Resour 13: 61–73.
- 43.
OECD (2013) Providing agri-environmental public goods through collective action. Paris: OECD. 306 p.
- 44. Curtis A, Lacy TD (1998) Landcare, stewardship and sustainable agriculture in Australia. Environ Values 7: 59–78.
- 45. Pannell DJ, Marshall GR, Barr N, Curtis A, Vanclay F, et al. (2006) Understanding and promoting adoption of conservation practices by rural landholders. Aust J Exp Agric 46: 1407–1424.
- 46.
Stubbs M (2014) Conservation Reserve Program (CRP): status and issues. Washington, DC: Congressional Research Service. 24 p.
- 47.
United States Department of Agriculture (2011) CRP benefits. http://www.fsa.usda.gov/Internet/FSA_File/united_states.pdf via the Internet. Accessed 14 March 2015.
- 48. Wu J (2000) Slippage effects of the conservation reserve program. Am J Agric Econ 82: 979–992.
- 49. Franks JR, McGloin A (2007) Joint submissions, output related payments and environmental co-operatives: Can the Dutch experience innovate UK agri-environment policy? Journal of Environmental Planning and Management 50: 233–256.
- 50. Sotherton NW (1998) Land use changes and the decline of farmland wildlife: An appraisal of the set-aside approach. Biol Conserv 83: 259–268.
- 51. Robinson GM, Lind M (1999) Set-Aside and environment: a case study in southern England. Tijdschr Econ Soc Geogr 90: 296–311.
- 52. Weeks ES, Walker SF, Dymond JR, Shepherd JD, Clarkson BD (2012) Patterns of past and recent conversion of indigenous grasslands in the South Island, New Zealand. N Z J Ecol 37: 127–138.
- 53. Caro D, Davis SJ, Bastianoni S, Caldeira K (2014) Global and regional trends in greenhouse gas emissions from livestock. Climatic Change 126: 203–216.
- 54. Brown MA, Clarkson BD, Stephens RT, Barton BJ (2014) Compensating for ecological harm–the state of play in New Zealand. N Z J Ecol 38: 139–146.
- 55.
Brown MA, Stephens RTT, Peart R, Fedder B (2015) Vanishing nature: facing New Zealand’s biodiversity crisis. Auckland: Environmental Defence Society. 208 p.
- 56.
Forest & Bird (2013) 2013 Annual Report. http://www.forestandbird.org.nz/files/file/FB%20Annual%20Report%202013%20V4%20low%20res.pdf via the Internet. Accessed 14 March 2015.
- 57. Abler D (2004) Multifunctionality, agricultural policy, and environmental policy. Agricultural and Resource Economics Review 33: 8–17.
- 58. Plantinga AJ (1996) the effect of agricultural policies on land use and environmental quality. Am J Agr Econ 78: 1082–1091.
- 59. MacDonald GK, Brauman KA, Sun S, Carlson KM, Cassidy ES, Gerber JS, et al. (2015) Rethinking agricultural trade relationships in an era of globalization. BioScience 65: 275–289.
- 60. Rudel TK, Schneider L, Uriarte M, Turner BL, DeFries R, Lawrence D, et al. (2009) Agricultural intensification and changes in cultivated areas, 1970–2005. Proc Natl Acad Sci USA 106: 20675–20680 pmid:19955435
- 61.
Murray BC (2008) Leakage from an avoided deforestation compensation policy: concepts, empirical evidence, and corrective policy options. Raleigh: Nicholas Institution for Environmental Policy Solutions. 32 p.
- 62. Pe’er G, Dicks LV, Visconti P, Arlettaz R, Báldi A, et al. (2014) EU agricultural reform fails on biodiversity. Science 344:1090–1092. pmid:24904142
- 63. Pretty JN, Brett C, Gee D, Hine RE, Mason CF, et al. (2000) An assessment of the total external costs of UK agriculture. Agric Syst 65: 113–136.
- 64. Pretty J, Brett C, Gee D, Hine RE, Mason CF, et al. (2001) Policy challenges and priorities for internalizing the externalities of modern agriculture. Journal of Environmental Planning and Management 44: 263–283.
- 65. Balmford A, Bruner A, Cooper P, Costanza R, Farber S, et al. (2002) Economic reasons for conserving wild nature. Science 297: 950–953. pmid:12169718
- 66. Kleijn D, Sutherland WJ (2003) How effective are European agri-environment schemes in conserving and promoting biodiversity? J Appl Ecol 40: 947–969.
- 67. Kleijn D, Baquero RA, Clough Y, Díaz M, De Esteban J, et al. (2006) Mixed biodiversity benefits of agri-environment schemes in five European countries. Ecol Lett 9: 243–254. pmid:16958888
- 68. Whittingham MJ (2007) Will agri-environment schemes deliver substantial biodiversity gain, and if not why not? J Appl Ecol 44: 1–5.
- 69. Baker DJ, Freeman SN, Grice PV, Siriwardena GM (2012) Landscape-scale responses of birds to agri-environment management: a test of the English Environmental Stewardship scheme. J Appl Ecol 49: 871–882.
- 70. Kleijn D, Berendse F, Smit R, Gilissen N (2001) Agri-environment schemes do not effectively protect biodiversity in Dutch agricultural landscapes. Nature 413: 723–725. pmid:11607029
- 71. Vickery JA, Bradbury RB, Henderson IG, Eaton MA, Grice PV (2004) The role of agri-environment schemes and farm management practices in reversing the decline of farmland birds in England. Biol Conserv 119: 19–39.
- 72.
State Forestry Administration of China (2014) Forestry in China. http://english.forestry.gov.cn/uploads/Information_Services/Latest_Publication/Forestry_in_China.pdf via the Internet. Accessed 14 March 2015.
- 73. Liu J, Li S, Ouyang Z, Tam C, Chen X (2008) Ecological and socioeconomic effects of China’s policies for ecosystem services. Proc Natl Acad Sci USA 105: 9477–9482 pmid:18621700
- 74.
National People's Congress of the People's Republic of China. (2014) China’s legislature adopts revised Environmental Protection Law. http://www.npc.gov.cn/englishnpc/news/Legislation/2014-04/25/content_1861275.htm via the Internet. Accessed 14 March 2015.
- 75. Sun B, Zhang L, Yang L, Zhang F, Norse D, et al. (2012) Agricultural non-point source pollution in china: causes and mitigation measures. Ambio 41: 370–379. pmid:22311715
- 76. Zhang W, Dou Z, He P, Ju X-T, Powlson D, et al. (2013) New technologies reduce greenhouse gas emissions from nitrogenous fertilizer in China. Proc Natl Acad Sci USA 110: 8375–8380. pmid:23671096
- 77. Ju X-T, Xing G-X, Chen X-P, Zhang S-L, Zhang L-J et al. (2009) Reducing environmental risk by improving N management in intensive Chinese agricultural systems. Proc Natl Acad Sci USA 106: 3041–3046. pmid:19223587
- 78.
OECD (2015) Producer and consumer support estimates database. Available http://www.oecd.org via the Internet. Accessed 14 March 2015.
- 79. Hodgson JA, Kunin WE, Thomas CD, Benton TG, Gabriel D (2010) Comparing organic farming and land sparing: optimizing yield and butterfly populations at a landscape scale. Ecol Lett 13:1358–1367. pmid:20825453
- 80. Phalan B, Onial M, Balmford A, Green RE (2011) Reconciling food production and biodiversity conservation: land sharing and land sparing compared. Science 333: 1289–1291. pmid:21885781
- 81. Godfray HCJ, Garnett T (2014) Food security and sustainable intensification. Phil Trans R Soc Lond 369: 20120273.
- 82. Fischer J, Abson DJ, Butsic V, Chappell MJ, Ekroos J, Hanspach J, et al. (2014) Land sparing versus land sharing: moving forward. Conserv Lett 7: 149–157.
- 83. Frishkoff LO, Karp DS, M’Gonigle LK, Mendenhall CD, Zook J, Kremen C, et al. (2014) Loss of avian phylogenetic diversity in neotropical agricultural systems. Science 345: 1343–1346. pmid:25214627
- 84. Mueller ND, Gerber JS, Johnston M, Ray DK, Ramankutty N, et al. (2012) Closing yield gaps through nutrient and water management. Nature 490: 254–257. pmid:22932270
- 85. Alix-Garcia JM, Shapiro EN, Sims KRE (2012) Forest conservation and slippage: evidence from Mexico’s national payments for ecosystem services program. Land Econ 88: 613–638.
- 86. Stavins RN, Whitehead BW (1992) Pollution charges for environmental protection: a policy link between energy and environment. Annual Review of Energy and the Environment 17: 187–210.
- 87. Newson SE, Johnston A, Renwick AR, Baillie SR, Fuller RJ (2012) Modelling large-scale relationships between changes in woodland deer and bird populations. J Appl Ecol 49: 278–286.
- 88. Chamberlain D E, Fuller RJ, Bunce RGH, Duckworth JC, Shrubb M (2000) Changes in the abundance of farmland birds in relation to the timing of agricultural intensification in England and Wales. J Appl Ecol 37: 771–788.
- 89. Bajželj B, Richards KS, Allwood JM, Smith P, Dennis JS, et al. (2014) Importance of food-demand management for climate mitigation. Nature Clim Change 4: 924–929.
- 90. Tilman D, Clark M (2014) Global diets link environmental sustainability and human health. Nature 515: 518–522. pmid:25383533
- 91. Pandya R (2014) Milk without the moo. New Sci 222: 28–29.
- 92. Gilroy JJ, Edwards FA, Uribe CAM, Haugaasen T, Edwards DP (2014) Surrounding habitats mediate the trade-off between land-sharing and land-sparing agriculture in the tropics. J Appl Ecol 51: 1337–1346.
- 93. Hobbs PR, Sayre K, Gupta R (2008) The role of conservation agriculture in sustainable agriculture. Phil Trans R Soc Lond B 363: 543–555.
- 94. Chen X-P, Cui Z-L, Vitousek PM, Cassman KG, Matson PA, et al. (2011) Integrated soil–crop system management for food security. Proc Natl Acad Sci USA 108: 6399–6404. pmid:21444818
- 95. Tester M, Langridge P (2010) Breeding technologies to increase crop production in a changing world. Science 327: 818–822. pmid:20150489
- 96. Bateman IJ, Harwood AR, Mace GM, Watson RT, Abson DJ, et al. (2013) Bringing ecosystem services into economic decision-making: land use in the United Kingdom. Science 341: 45–50. pmid:23828934
- 97. Anderson K, Nelgen S (2013) Updated national and global estimates of distortions to agricultural incentives, 1955 to 2011. Available: http://www.worldbank.org/agdistortions via the Internet. Accessed 2015 June 1.
- 98. Anderson K, Kurzweil M, Martin W, Sandri D, Valenzuela E (2008) Measuring distortions to agricultural incentives, revisited. World Trade Rev 7: 1–30.