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3. General policy responses What should be the policy response to these challenges? The next two paragraphs describe the recommendations in the UK Government’s Foresight study The Future of Food and Farming (Foresight, 2011) which are in line with most recent analyses.
First, the likelihood of there being major problems ahead is sufficiently high that action is needed throughout the food system. Certainly more food will need to be produced, but in addition diets will need to change, especially in the rich world.
Second, the food system will need to be made more efficient, its governance improved and the amount of food waste reduced – perhaps 30% of all food produced is, for different reasons, never used. Third, sustainability must move centre stage in food policy. We shall need to be much more efficient in our use of inputs to reduce the negative environmental externalities of excessive water consumption and over-use of nitrogen. Food production will need to adapt to climate change and play its part in mitigation – by greater efficiency and by using agricultural land to lock up carbon.
Finally, in an ever more globalised world the moral imperative to reduce hunger and poverty is increasingly aligned with the self-interests of the rich world who will not be able to escape the consequences of famine and food scarcity in least-developed countries.
In the past one of the main options to increase food supply was to increase the area under cultivation and even today there are considerable tracts of land that might be brought into agriculture. But this land is often forested, wetlands, or ancient grassland.
Conversion to agriculture would liberate large quantities of greenhouse gases and would risk major exacerbation of climate change. Indeed, food security is intimately linked to climate change because if we fail on the former it will be much harder to address the latter. The world must thus operate on the assumption that to a good approximation there is no new land for agriculture (though restoration of degraded farmland will often be a priority). Therefore, more must be produced from the same area of land, and this must be done with less effect on the environment. This has been called sustainable intensification (Royal Society, 2009) and working out how it may be achieved is the greatest supply-side challenge in the coming decades. Much can be done using existing knowledge, especially if a pluralistic approach is taken, picking the best of all types of agricultural practice, from advanced conventional, through organic and agroecological approaches to learning from the experience and knowledge of indigenous peoples. But new research is also needed, not only to increase yield and productivity but also to maintain current yields in the face of new challenges from global change, from biological challenges such as weeds, pests and diseases that are continually evolving to exploit crops and livestock. It will also be important to address the particular needs of the world’s poorest who have not benefitted from the scientific advances enjoyed by more wealthy food producers.
4. Nitrogen and food security Nitrogen is one of the most important requirements for plant growth and the invention of the Haber-Bosch process in the early twentieth century that allowed for the relatively cheap manufacture of artificial fertilisers must rank as one of the most important scientific breakthroughs of all time (Smil, 2001). Cheap artificial fertilisers enabled the green revolution to occur and for hunger to be ended in many parts of the world (Evenson and Gollin, 2003). Nitrogen is also the single most important environmental pollutant produced by agriculture: nitrates entering the hydrological
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cycle contaminate human drinking water and pollute rivers, lakes and the ocean, often leading to drastic reductions in biodiversity through eutrophication. Ammonia and other nitrogen compounds enter the atmosphere from farmland and are deposited on natural habitats, altering the ecological balance and in some areas rendering impossible the persistence of the highly diverse plant communities often associated with low nutrient soils (Vitousek et al., 1997). Agriculturally derived nitrous oxide (N2O) is directly emitted from N fertiliser application, N deposited by domesticated animals, nitrogen fixation and mineralisation of N residues in soils. In addition, agriculture contributes significantly to the emission of carbon dioxide and methane (Stern, 2007). Nitrogen is both bane and boon to mankind.
What are the challenges to the research community involved in nitrogen as the world grapples with food security and the need for sustainable intensification? The first is straightforward and obvious – nitrogen needs to be used more efficiently. There are at least four different strands to increasing efficiency.
There is much we can do with existing knowledge, especially if techniques from all types of agriculture are considered (Dawson and Hilton, 2011). Many agronomic techniques for different crops and cropping systems have been developed that get the fertiliser to the places where it is needed by the crop and at the right times, as well as retain nitrogen in the field and reduce losses (Day, 2011). These methods involve reduced application of artificial fertiliser and the more efficient use of manures and nitrogen fixing plants (including grass-clover lays and legume rotations etc.). The barriers to the wider take up of these methods are often insufficient skills and human capital, particular acute in areas where extension services are poorly developed (Foresight, 2011).
Increasing nitrogen efficiency should be a major goal of agronomic research. At the more high-tech end of the research spectrum different forms of precision agriculture can greatly reduce the amount of fertiliser that needs to be applied, while plants can be bred (using conventional and GM techniques) to take up and utilise nitrogen more efficiently (Dunwell, 2011). Looking further into the future it may be possible to engineer nitrogen fixation into grains and other crops. Hightech research is attractive to the private sector as it generates IP but the importance of low-tech research to improve efficiency through better farming practices and soil management is equally as important and will likely require public funding (IAASTD, 2008) The behavioural economics of fertiliser application is complex and often not properly appreciated. Incorrect incentives can be set, such as in China where in some places extension workers were paid by kilogram of fertiliser offloaded on farmers, leading to dire pollution and in some cases crop stunting by nitrogen poisoning. Individual farmers will sometimes apply more fertiliser than economically rational because they are risk averse, or just because it is perceived as the right thing to do. Fertiliser manufacturers clearly have no interest in lessening this behaviour.
Nitrogen application is a classic example of an action whose benefits are reaped by the actor but whose harm is experienced by other people, for example people drinking water from the same catchment, or the global population in the case of greenhouse gas emissions. These are negative externalities whose costs do not influence farmer behaviour. There are different ways that these negative externalities can be reduced. The major one in most developed countries is through regulation (for example the EU Nitrates Directive and Water Framework Directive). An alternative would be to “internalise the externalities” by for Nitrogen Workshop 2012 example a nitrogen tax, though the effect this would have on food prices would need careful attention (Bateman et al., 2011).
Increasing efficiency without decreasing yields is an uncontroversial example of a “win-win” but by how much should yields be sacrificed to reduce negative externalities (typically in high-income countries) or increased pollution accepted as a price for increased yield (for example in low-income countries). There is no simple answer to this as the amount of food the world will need to produce in the coming decades depends on progress made on the demand side (restraining population growth, changing diets), and on efficiency (such as reducing waste) and better governance. But in thinking about these issues it is important to take several things into account.
First, the critical issue in comparing farming systems is not kg N fertiliser ha-1 or pollutant loading ha-1 but kg N fertiliser per kg food produced. There are indirect consequences of reducing yields that must be considered in assessing alternatives.
The consequences for global greenhouse gas emissions of the Green Revolution and in particular the direct and indirect effects of increased nitrogen use (the latter including, for example, the energy used in fertiliser application and the Haber-Bosch process) are rightly highlighted as an issue demanding greater efficiency. Yet if the same amount of food was produced through extensification and in particular through land conversion, the greenhouse gas emissions would have been much worse (Burney et al., 2010). A study comparing land conversion and increased nitrogen application as alternative means of increasing substantially food supply by mid-century again came firmly down in favour of fertilisers (Tilman et al., 2011). Conversion of land can also have drastic effects on biodiversity and for some habitat types, tropical rainforests in particular, there is a growing evidence base that land “sparing” is a better strategy to conserve biodiversity than land “sharing” (Phalan et al., 2011). Such strategies will require both elevated yields on existing farmland, as well as a land use governance system that delivers “spared land” in the face of strong and conflicting contrary interests. Second, there is evidence that subsidising fertilisers in least developed countries may stimulate agriculture to move from subsistence to small business scales (Dorward and Chirwa, 2011). It may increase local food production, increase local incomes, and perhaps put money into sections of society that are hard to reach through other routes. But there are potential negative consequences that it will be important to try to minimise. Increased nitrogen application may lead to pollution, especially if subsidies are such that there are little incentives to be efficient. Input subsidies clearly distort markets and world trade negotiations are aimed at reducing them, though transitory special arrangements are allowed for poor nations.
Nevertheless, as some countries are finding, removing subsidies can be politically very difficult, even when they are becoming a drain on national finances (Wiggins and Brooks, 2010). More economic and political science research on fertiliser subsidies would be helpful.
5. Conclusions The last fifty years have been unusual in human history in that for large parts of the world food has been plentiful and cheap and a low priority for governments and policy makers. The next fifty years will be unusual for other reasons: it is highly likely (but not certain) that human populations will peak while mankind will come to dominate virtually all the biogeochemical cycles including the nitrogen cycle. But though population growth will decelerate there will still be many more (and more
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wealthy) mouths to feed, at a time when competition for water and land will be intensive and the effects of climate change becoming stronger. We shall need to moderate demand, reduce waste, and improve the governance food system, but in addition we shall need to grow more but with less effects on the environment. A greater understanding of how nitrogen, in its many forms, can be used to increase yields in ways that do not damage the environment and compromise future food production (and other ecosystem services) will be critical to achieve sustainable food security.
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