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Global yields of major crops are analysed using climate, irrigation and new nutrient data to show that large production increases are possible from closing yield gaps to 100% of attainable yields, and that changes in management practices needed to close yield gaps vary considerably by region and current intensity. How and where to feed the world Many crops, particularly those grown in developing countries, produce considerably less than their theoretically attainable yields. This study uses global data on yields for 17 major crops, along with climate, irrigation and nutrient data, to show where yields could be increased with either nutrient addition or irrigation, and where overuse of nutrients and water could be cut without reducing yields. The resulting map identifies regions where it should be possible to decrease the environmental impact of agriculture by eliminating nutrient overuse, while still allowing an approximately 30% increase in major cereal production. In the coming decades, a crucial challenge for humanity will be meeting future food demands without undermining further the integrity of the Earth’s environmental systems 1 , 2 , 3 , 4 , 5 , 6 . Agricultural systems are already major forces of global environmental degradation 4 , 7 , but population growth and increasing consumption of calorie- and meat-intensive diets are expected to roughly double human food demand by 2050 (ref. 3 ). Responding to these pressures, there is increasing focus on ‘sustainable intensification’ as a means to increase yields on underperforming landscapes while simultaneously decreasing the environmental impacts of agricultural systems 2 , 3 , 4 , 8 , 9 , 10 , 11 . However, it is unclear what such efforts might entail for the future of global agricultural landscapes. Here we present a global-scale assessment of intensification prospects from closing ‘yield gaps’ (differences between observed yields and those attainable in a given region), the spatial patterns of agricultural management practices and yield limitation, and the management changes that may be necessary to achieve increased yields. We find that global yield variability is heavily controlled by fertilizer use, irrigation and climate. Large production increases (45% to 70% for most crops) are possible from closing yield gaps to 100% of attainable yields, and the changes to management practices that are needed to close yield gaps vary considerably by region and current intensity. Furthermore, we find that there are large opportunities to reduce the environmental impact of agriculture by eliminating nutrient overuse, while still allowing an approximately 30% increase in production of major cereals (maize, wheat and rice). Meeting the food security and sustainability challenges of the coming decades is possible, but will require considerable changes in nutrient and water management.

Achieving sustainable global food security is one of humanity's contemporary challenges. Here we present an analysis identifying key \"global leverage points\" that offer the best opportunities to improve both global food security and environmental sustainability. We find that a relatively small set of places and actions could provide enough new calories to meet the basic needs for more than 3 billion people, address many environmental impacts with global consequences, and focus food waste reduction on the commodities with the greatest impact on food security. These leverage points in the global food system can help guide how nongovernmental organizations, foundations, governments, citizens' groups, and businesses prioritize actions.

As the demands for food, feed and fuel increase in coming decades, society will be pressed to increase agricultural production - whether by increasing yields on already cultivated lands or by cultivating currently natural areas - or to change current crop consumption patterns. In this analysis, we consider where yields might be increased on existing croplands, and how crop yields are constrained by biophysical (e.g. climate) versus management factors. This study was conducted at the global scale. Using spatial datasets, we compare yield patterns for the 18 most dominant crops within regions of similar climate. We use this comparison to evaluate the potential yield obtainable for each crop in different climates around the world. We then compare the actual yields currently being achieved for each crop with their 'climatic potential yield' to estimate the 'yield gap'. We present spatial datasets of both the climatic potential yields and yield gap patterns for 18 crops around the year 2000. These datasets depict the regions of the world that meet their climatic potential, and highlight places where yields might potentially be raised. Most often, low yield gaps are concentrated in developed countries or in regions with relatively high-input agriculture. While biophysical factors like climate are key drivers of global crop yield patterns, controlling for them demonstrates that there are still considerable ranges in yields attributable to other factors, like land management practices. With conventional practices, bringing crop yields up to their climatic potential would probably require more chemical, nutrient and water inputs. These intensive land management practices can adversely affect ecosystem goods and services, and in turn human welfare. Until society develops more sustainable high-yielding cropping practices, the trade-offs between increased crop productivity and social and ecological factors need to be made explicit when future food scenarios are formulated.

Biofuels from land-rich tropical countries may help displace foreign petroleum imports for many industrialized nations, providing a possible solution to the twin challenges of energy security and climate change. But concern is mounting that crop-based biofuels will increase net greenhouse gas emissions if feedstocks are produced by expanding agricultural lands. Here we quantify the ‘carbon payback time’ for a range of biofuel crop expansion pathways in the tropics. We use a new, geographically detailed database of crop locations and yields, along with updated vegetation and soil biomass estimates, to provide carbon payback estimates that are more regionally specific than those in previous studies. Using this cropland database, we also estimate carbon payback times under different scenarios of future crop yields, biofuel technologies, and petroleum sources. Under current conditions, the expansion of biofuels into productive tropical ecosystems will always lead to net carbon emissions for decades to centuries, while expanding into degraded or already cultivated land will provide almost immediate carbon savings. Future crop yield improvements and technology advances, coupled with unconventional petroleum supplies, will increase biofuel carbon offsets, but clearing carbon-rich land still requires several decades or more for carbon payback. No foreseeable changes in agricultural or energy technology will be able to achieve meaningful carbon benefits if crop-based biofuels are produced at the expense of tropical forests.

Aggressive renewable energy policies have helped the biofuels industry grow at a rate few could have predicted. However, while discourse on the energy balance and environmental impacts of agricultural biofuel feedstocks are common, the potential they hold for additional production has received considerably less attention. Here we present a new biofuel yield analysis based on the best available global agricultural census data. These new data give us the first opportunity to consider geographically-specific patterns of biofuel feedstock production in different regions, across global, continental, national and sub-national scales. Compared to earlier biofuel yield tables, our global results show overestimates of biofuel yields by ~100% or more for many crops. To encourage the use of regionally-specific data for future biofuel studies, we calculated complete results for 20 feedstock crops for 238 countries, states, territories and protectorates.

Feeding a growing world sustainably In the coming years, continued population growth, rising incomes, increasing meat and dairy consumption and expanding biofuel use will place unprecedented demands on the world's agriculture and natural resources. Can we meet society's growing food needs while reducing agriculture's environmental harm? Here, an international team of environmental and agricultural scientists uses new geospatial data and models to identify four strategies that could double food production while reducing environmental impacts. First, halt agricultural expansion. Second, close 'yield gaps' on underperforming lands. Third, increase cropping efficiency. And finally, we need to change our diets and shift crop production away from livestock feed, bioenergy crops and other non-food applications. Increasing population and consumption are placing unprecedented demands on agriculture and natural resources. Today, approximately a billion people are chronically malnourished while our agricultural systems are concurrently degrading land, water, biodiversity and climate on a global scale. To meet the world’s future food security and sustainability needs, food production must grow substantially while, at the same time, agriculture’s environmental footprint must shrink dramatically. Here we analyse solutions to this dilemma, showing that tremendous progress could be made by halting agricultural expansion, closing ‘yield gaps’ on underperforming lands, increasing cropping efficiency, shifting diets and reducing waste. Together, these strategies could double food production while greatly reducing the environmental impacts of agriculture.

In the post-millennium period, the photobook has become a central form for the presentation and dissemination of photographic works by contemporary practitioners. As interest in the medium has increased rapidly, so too have the communities, dedicated events, platforms and competitions which shape the photobook world. Yet there is little critical discourse accompanying this new age of the photobook, and where consideration of the medium exists, it tends towards maker-centric or art-historical discourse. In response, and in a continuation of The Photobook Club project, this research sets out to critically interrogate what happens in the space between the production and reception of the contemporary photobook. In doing so this work addresses not only the making, but the making public, of the medium. The thesis begins by opening up the photographic canon, a process which tethers the newly unified term ‘photobook’ to a taxonomy of photographic relationships with the page, termed ‘lineages’. The specificity of critique this enables is employed first in an investigation into how the contemporary photobook is impacted by networked technologies in the guise of postphotography and post digitality. Aided by content analysis and framed within Michael Bhaskar’s theory of publishing, the research witnesses a number of contemporary design and production trends in response to, and adoption of, new technologies: with different effects across the lineages. Subsequently, attention is turned to the photobook world with extensive surveys, elite interviews and discourse analysis providing a detailed account of an emergent community whose tendency towards production and sophistication has contributed to the contemporary photobook being seen as a new form of a longstanding medium. Finally, literary and montage theory is combined with empirical research, which employs graphical elicitation, in order to provide the first research-informed account of photobook reading. Through the contributions this research makes to the field of study in an ethnographic review of community and discourse; a historical and contemporary contextualisation; and an account of photobook reading, it is able to demonstrate how the photobook is forging stronger connections with engaged and like minded readers, whilst excluding others. As response, the research is structured by, and concluded with, a proposed critical framework for the contemporary photobook, which connects the maker, scholar and reader, and provides a set of potential tools to interrogate the purpose, realisation and impact of a range of photographic publications. In this way, the research brings together photographic and publishing discourses with a focus on the ground between making and reading, seeking to allow stronger and more informed connections between authors and existing, as well as potential, readers.