[Southern California Permaculture] healthy diets from sustainable food systems
jcalvert at crystal3.com
Fri Jan 18 14:18:46 PST 2019
*Food in the Anthropocene: the EAT–Lancet Commission on healthy diets from sustainable food systems*
Strong evidence indicates that food production is among the largest drivers of global environmental change by contributing to climate change, biodiversity loss, freshwater use, interference with the global nitrogen and phosphorus cycles, and land-system change (and chemical pollution, which is not assessed in this Commission).
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The current global food system is unsustainable and requires an agricultural revolution that is based on sustainable intensification and driven by sustainability and system innovation. This change would entail reducing yield gaps on cropland, radical improvements in the efficiency of fertiliser and water use, recycling phosphorus, redistributing global use of nitrogen and phosphorus, implementing climate mitigation options, including changes in crop and feed management, and enhancing biodiversity within agricultural systems.
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Anthropogenic emissions of greenhouse gases cause climate change, which leads to disruptions in the Earth system, such as sea-level rise and increasing frequency of extreme weather events.151 Systems of food production release greenhouse gases (eg, carbon dioxide, methane, and nitrous oxide) into the atmosphere directly and drive land use change that releases additional carbon dioxide when forests are cleared, wetlands drained, and soils are tilled. Food production is a prime source of methane, and nitrous oxide, which have 56 times and 280 times the global warming potential (over 20 years) of carbon dioxide, respectively.151 Methane is produced during digestion in ruminant livestock, such as cows and sheep, or during anaerobic decomposition of organic material in flooded rice paddies. Nitrous oxide mainly arises from soil microbes in croplands and pastures and is affected by soil fertility management, such as fertiliser application. Carbon dioxide is released by agricultural
land from tillage of soils and during burning to clear land of plants, soil, organic matter, and agricultural residues, and from burning fossil fuels by farm machinery, for production of fertilisers, and in transport of agricultural products. Carbon dioxide is also released when converting natural ecosystems, especially forests, to agriculture.
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*Food production as a driver of biodiversity loss*
Multiple human actions contribute to biodiversity loss. Terrestrial and aquatic habitat loss, habitat fragmentation, climate change, chemical pollution, invasive species, and unsustainable harvest of wild species have been identified as primary drivers.190,196 However, habitat loss and fragmentation, particularly through human appropriation of land for food production, is the greatest driver of biodiversity loss.190,197 Based on the International Union for Conservation of Nature classification of bird and mammal extinction risks, 80% of extinction threats to mammal and bird species are due to agriculture (appendix p 17).
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Staying within the boundary for climate change can be achieved by *consuming plant-based diets*. Improved production practices are less effective than a shift to healthy diets in abating food-related greenhouse-gas emissions because most emissions are associated with production of animal source foods whose characteristics, such as enteric fermentation in ruminants, have little potential for change. Increasing shift toward more plant-based diets will enable food production to stay within the climate change boundary.
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