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Researchers from the University of Oxford’s Environmental Change Institute (of which the FCRN is part) have created a new tool - the “temperature of equivalence” - to map the impacts of varying degrees of climate change in different areas. They find that people living in low-income countries will, on average, experience heat extremes at 1.5°C of (global average) warming that people living high-income countries will not encounter until 3°C. This result is based on combining a map of predicted heat extremes with information on where people actually live within these areas. The paper also finds that, on average, people in high-income countries would experience the same increase in extreme rainfall after 1.0°C of warming that people in low-income countries would experience at 1.5°C of warming.
A group of researchers from the University of Michigan’s Sustainable Food Systems Initiative has called for a new approach to solving food system problems, based on the intersection of four key areas: the ecology of agroecosystems, equity on a global and local scale, cultural dimensions of food and agriculture, and human health.
A new paper finds that the global marine fishing fleet produces greenhouse gas emissions equivalent to 4% of the total emissions from global food production. The types of fisheries with the highest emissions intensity per unit of catch are those using motorised craft (vs. non-motorised), those harvesting for human consumption (vs. catches used for meal, oil or non-food uses), fishing for crustaceans (vs. other species types) and fisheries in China (vs. those in other regions).
A new paper in Science reviews trends in meat consumption and the associated health and environmental implications. The paper also discusses potential means of influencing meat consumption levels.
Scientists used DNA barcoding (testing a short section of the genome) to check whether fish in Metro Vancouver are really the species that they are labelled as being. They found that 25% of fish sampled were mislabelled, with error rates higher in restaurants than in grocery stores or sushi bars. Since the price of the claimed species was often higher than that of the real species, the paper suggests that some labelling may be intentional. However, the paper also suggests that some errors could be due to confusion between vernacular fish names (rather than scientific species names).
This paper surveys 195 cities in the United States and finds that the number of water conservation measures adopted in a city depend on both the climate (drier cities tend to have more water conservation measures than wetter cities) and political leanings (cities that lean towards the Democrats have more water conservation measures than Republican-leaning cities).
Managing tropical forest conservation on the basis of maximising carbon storage might not protect the most biodiverse regions of forest, according to a recent paper. Using datasets from Brazil, the authors found that the correlation between biodiversity and levels of carbon stored in forests depended on whether and how the forest had been disturbed by human activity.
As global mean temperature rises due to climate change, the chance of multiple shocks in maize production occurring at the same time rises, due to greater variability in yields. The top four maize-producing countries are United States, China, Brazil, and Argentina. The chance of all four suffering a yield loss of more than 10% in the same year is presently almost zero, but rises to 6% for 2°C of warming and 87% for 4°C of warming. The study does not account for changing variability in temperature (only the increase in mean temperature), nor any gains from breeding heat-tolerant maize varieties.
This review paper reports that organic agriculture has lower yields than conventional agriculture, by 19-25% on average across all crops, according to three meta-analyses. Lower yields may be due to the lack of use of synthetic fertilisers - organic systems are often limited by low levels of nitrogen or phosphorus - and higher susceptibility to pest outbreaks. Widespread uptake of organic farming (to produce the same amounts of output as today) would probably require some conversion of natural habitats to farmland, because of this lower land-use efficiency compared to conventional agriculture - an important consideration, as the area of certified organic production has increased from 15 million ha in 2000 to 51 million ha in 2015 (although this is only 1% of agricultural land).
Current crop production levels could feed a population of 9.7 billion people in 2050, according to a recent paper, but only in a future in which there are socio-economic changes, significant shifts in diets towards plant-based foods, and limited biofuel production. Without dietary changes, crop production would have to increase by 119% by 2050.
A recent paper assesses the carbon implications of converting Indonesian rainforests to oil palm monocultures, rubber monocultures or rubber agroforestry systems (known as “jungle rubber”). It finds that carbon losses are greatest from oil palm plantations and lowest from jungle rubber systems, in all cases being mainly from loss of aboveground carbon stocks. The paper points out that, “Thorough assessments of land-use impacts on resources such as biodiversity, nutrients, and water must complement this synthesis on C but are still not available.”
Smallholders with farms under two hectares produce 28–31% of all crops and 30–34% of all food supply on 24% of the world’s agricultural land, according to a new paper. This contrasts with common claims that smallholders produce 70–80% of the world’s food. The paper also finds that, relative to larger farms, farms under two hectares have greater crop species diversity, allocate less of their crop outputs towards feed and processing and are important suppliers of fruit, pulses, roots and tubers.
Our thanks go to FCRN member Emma Garnett for bringing to our attention a recent paper that investigates how land use could change if consumption were to shift away from meat and towards seafood from aquaculture. Aquaculture systems frequently use feed that is made from land-based crops. The paper studied two aquaculture-heavy scenarios (one using only marine aquaculture, and one using the current ratio of marine to freshwater aquaculture) where all additional meat consumption in 2050 (compared to today) is replaced by aquaculture products. Compared to a business-as-usual scenario for 2050, the aquaculture scenarios use around one-fifth less land to produce feed crops, because of the relative efficiency of aquatic organisms (compared to land-based animals) in converting feed into food that can be eaten by humans.
FCRN member Dr Rosemary Green of the London School of Hygiene & Tropical Medicine has published a paper that calculates the greenhouse gas (GHG) emissions and water use associated with five dietary patterns in India. As shown below, GHG emissions per capita are highest for the “rice and meat” dietary pattern (at 1.2 tonnes CO2 eq. per year) and lowest for the “wheat, rice and oils” pattern (at 0.8 tonnes CO2 eq. per year). For comparison, per capita dietary GHG emissions in the UK have been estimated at 2.6 tonnes CO2 eq. per year for high meat eaters and 1.1 tonnes CO2 eq. per year for vegans (Scarborough et al., 2014). Water use is highest for the “wheat, rice and oils” pattern and lowest for the “rice and low diversity” pattern.
This paper reports on a systematic review of grocery store interventions undertaken to evaluate their effectiveness in changing food purchasing behaviours, and to examine whether this effectiveness varied with intervention components, setting, or socioeconomic status. This is the first paper to synthesise evidence from randomised controlled trials (RCTs) in grocery stores across a wide range of intervention types.
FCRN member Waleed Fouad Abobatta of the Agriculture Research Centre, Egypt, has published a paper on the applications of nanotechnology in agriculture. FCRN readers may be particularly interested in the use of nanotechnology to reduce use of fertilisers and pesticides through greater application efficiency.
A study has found that people who view vegetarianism as a threat to their way of life, and those who believe in human supremacy over animals, are likely to have fewer animal species that they view as worthy of moral consideration (compared to people who do not see vegetarianism as a threat or who do not believe in human supremacy over animals). Moral attitudes varied strongly towards different animal species, for example, 90% of participants a felt moral obligation to care for the welfare of dogs, compared to 51% who felt the same obligation for pigs.