Food waste, another scenario analysed by the team, occurs at all stages in the food chain. In developing countries, poor storage and transportation cause waste; in the west, wasteful consumption is rife. "The latter is in many ways worse because the wasted food products have already undergone various transformations that require input of other resources, especially energy," said Bajzelj.
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.
"This is not a radical vegetarian argument; it is an argument about eating meat in sensible amounts as part of healthy, balanced diets," said Cambridge co-author Prof Keith Richards. "Managing the demand better, for example by focusing on health education, would bring double benefits maintaining healthy populations, and greatly reducing critical pressures on the environment."
Co-author Prof Pete Smith from the University of Aberdeen said: "unless we make some serious changes in food consumption trends, we would
|Contact: Fred Lewsey|
University of Cambridge