Is global dietary change an effective strategy to curb climate change?

Bradfield, James; Trigueiro, Helena; Ray, Sumantra

Research has shown that we are currently not doing this—822 million people are undernourished, a fact linked with almost half of child mortality globally.2 However, the solution to this problem cannot simply be to produce more food, particularly when the Food and Agriculture Organization of the United Nations estimates that one-third of all food produced for human consumption is lost or wasted.3 The need for change is reflected in the United Nations’ Sustainable Development Goal 2.4 which aims to improve the sustainability of food production, increasing productivity while maintaining ecosystems, by 2030. Producing 1 kg of lamb or mutton requires 369.81 m2 of land compared with 12.22 m2 for 1 kg of poultry meat and 2.97 m2 for 1 kg of farmed prawns.5 Examining greenhouse-gas emissions associated with production of 1 kg of beef, poultry and root vegetables, it tells a similar story with 60, 6 and 0.4 kg CO2/kg, respectively.5 Irrigating cropland is the largest human use of freshwater, accounting for 66% of annual resources, while food production is responsible for approximately 30% of the global greenhouse-gas emissions.6 7 There has been significant coverage in the last number of years in strategies to adopt a plant based diet. If greenhouse-gas emissions continue along their current trajectory, vegetable and legume production could decrease by 35% by 2100 due to water shortage and amplified salinity.15 In the same time period, corn production may be cut by half by a 4º C increase in global temperatures, while a temperature increase of under 2º C (in line with the Paris Climate Accord) could possibly reduce American corn production by approximately 18%.16 From a dietary point of view, there are three universal challenges: obesity, undernutrition and climate change.