Redefining agricultural yields: from tonnes to people nourished per hectare
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Redefining agricultural yields: from tonnes to people nourished per hectare
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CC Attribution 3.0 Unported:
You are free to use, adapt and copy, distribute and transmit the work or content in adapted or unchanged form for any legal purpose as long as the work is attributed to the author in the manner specified by the author or licensor. |
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2013
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English
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Abstract |
Worldwide demand for crops is increasing rapidly due to global population growth, increased biofuel production, and changing dietary preferences. Meeting these growing demands will be a substantial challenge that will tax the capability of our food system and prompt calls to dramatically boost global crop production. However, to increase food availability, we may also consider how the world's crops are allocated to different uses and whether it is possible to feed more people with current levels of crop production. Of particular interest are the uses of crops as animal feed and as biofuel feedstocks. Currently, 36% of the calories produced by the world's crops are being used for animal feed, and only 12% of those feed calories ultimately contribute to the human diet (as meat and other animal products). Additionally, human-edible calories used for biofuel production increased fourfold between the years 2000 and 2010, from 1% to 4%, representing a net reduction of available food globally. In this study, we re-examine agricultural productivity, going from using the standard definition of yield (in tonnes per hectare, or similar units) to using the number of people actually fed per hectare of cropland. We find that, given the current mix of crop uses, growing food exclusively for direct human consumption could, in principle, increase available food calories by as much as 70%, which could feed an additional 4 billion people (more than the projected 2–3 billion people arriving through population growth). Even small shifts in our allocation of crops to animal feed and biofuels could significantly increase global food availability, and could be an instrumental tool in meeting the challenges of ensuring global food security.
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worldwide demand for crops is increasing rapidly due to global population growth increased biofuel production and also changing dietary preferences a recent study estimates that by 2050 crop production will have to
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roughly double in order to meet demands
00:24
so meaning these demands for crops will be a substantial challenge 1 that taxes the capability of our food system but to increase global food
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availability we can also look at the
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crops that were currently growing and how were using
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them to see if we can feed more people
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with current levels of crop production Of
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particular interest are the crops that we use for animal feed and biofuels
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currently 36 per cent of all produce calories are used for animal feed
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and we find that of those animal feed calories only 12 per cent and that
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contributing to human diets in the form of animal products now the we know not all of
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crop production is used for human food this study reexamines agricultural
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productivity from its standard definition of
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yield were tons per hectare to the actual number of people that were able to feed
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per hectare of land we examine the
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production and allocation of 41 crops globally to determine what fraction of all produced calories are delivered to the food system or in other words what fraction of the calories that we produce actually become food that you and I can eat Fig. 1 and the main text shows a map of the proportion of the calories they're actually become food we can see from this map that areas in the green a high proportion of the calories that they produce actually become food whereas the areas in the red or a small proportion of the calories that they produce actually become food 1 of the major findings of our paper is that only 59 per cent of the calories we produce some croplands actually become food in other words we're losing 41 per cent of the calories that we produce on crop plants and most of this loss is happening due to inefficient feed to animal products conversion calorie
02:13
delivery fractions differ a lot by country though in the US for example 67 per cent of calories produced go animals for feed so if we look at all of the calories produced on U.S. croplands only 34 per cent of those calories actually become food when we look at the
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number of people that we could feed on the calories that were currently producing versus the number of people were actually feeding when you factor in proper location a livestock conversions we find a huge potential in countries such as the United States China and Brazil when we look at the number of people
02:53
that we could feed on produced calories we find that on average we could be about 10 people per hectare but when we look at the number of people were actually feeling given crop allocations in livestock conversions were only feeding about 6 people per hectare shifting
03:12
crops from their current mix of users to all food for human consumption could increase calorie availability by 70 per cent and that's enough calories to feed an additional 4 billion people we also find that
03:26
even small changes in diet like shifting away from beef to poultry and pork
03:31
or shifting from me to an
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overlap to a vegetarian diet could
03:36
increase the conversion efficiency and provide enough additional calories
03:41
for over 800 million people
03:44
considering the number of people that per hectare is important for the future food security also recent cropland expansion into the tropics has come a tremendous ecological costs in this study we demonstrate that even small changes in diets warships in crop allocations can have big benefits on agricultural productivity
