HEALTHIER DIETS and reducing food waste are both needed to ensure food security and avoid dangerous climate change, say the research team behind a new study.
Research from Cambridge and Aberdeen universities has estimated that if current food and lifestyle trends continue, food production alone will reach the global targets for total greenhouse gas (GHG) emissions in 2050.
The study’s authors say that we all need to think carefully about the food we choose and its environmental impact. A shift to healthier diets across the world is just one of a number of actions that need to be taken to avoid dangerous climate change: “If we maintain ‘business as usual’, then by 2050 cropland will have expanded by 42% and fertiliser use increased sharply by 45% over 2009 levels. A further tenth of the world’s pristine tropical forests would disappear over the next 35 years.”
The study shows that increased deforestation, fertilizer use and livestock methane emissions are likely to cause GHG from food production to increase by almost 80%.
Lead researcher Bojana Bajzelj from the University of Cambridge’s Department of Engineering, said: “The average efficiency of livestock converting plant feed to meat is less than 3%, and as we eat more meat, more arable cultivation is turned over to producing feedstock for animals that provide meat for humans. The losses at each stage are large, and as humans globally eat more and more meat, conversion from plants to food becomes less and less efficient, driving agricultural expansion and land cover conversion, and releasing more greenhouse gases. Agricultural practices are not necessarily at fault here – but our choice of food is.”
“It is imperative to find ways to achieve global food security without expanding crop or pastureland. Food production is a main driver of biodiversity loss and a large contributor to climate change and pollution, so our food choices matter.”
One scenario investigated by the team is on the supply side: the closing of ‘yield gaps’. Gaps between crop yields achieved in ‘best practice’ farming and the actual average yields exist all over the world, but are widest in developing countries – particularly in Sub-Saharan Africa. The researchers say that closing these gaps through sustainable intensification of farming should be actively pursued.
Yield gap closure alone still showed a greenhouse gas increase of just over 40% by 2050. Closing yield gaps and halving food waste still showed a small increase of 2% in greenhouse gas emissions. When healthy diets were added, the model suggests that all three measures combined result in agricultural GHG levels almost halving from their 2009 level – dropping 48%.
“Western diets are increasingly characterised by excessive consumption of food, including that of emission-intensive meat and dairy products. We tested a scenario where all countries were assumed to achieve an average balanced diet – without excessive consumption of sugars, fats, and meat products. This significantly reduced the pressures on the environment even further,” said the team.
The ‘average’ balanced diet used in the study is a relatively achievable goal for most. For example, the figures included two 85g portions of red meat and five eggs per week, as well as a portion of poultry a day.
To read more about the study click here.
