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Study Provides Carbon Footprint Table for Food

Researchers have compiled the first comprehensive carbon footprint table for fresh food so that chefs, caterers and foodies can cook meals without cooking the planet.

A/Prof Karli Verghese and Dr Enda Crossin of RMIT University, working with Dr Stephen Clune of Lancaster University, identified a clear greenhouse gas emissions hierarchy across food categories. Grains, fruit and vegetables had the lowest impact, followed by nuts and pulses. Meat from non-ruminant animals, such as chicken and pork, had a medium impact.

Fish also had a medium impact on average, although results between species varied significantly. Meat from ruminant animals, such as beef and lamb, had the highest impact.

The research, to be published in January in the Journal of Cleaner Production, reviewed 369 published studies that provided 1718 global warming potential values for 168 varieties of fresh produce, including vegetables, fruit, dairy products, staples, meat, chicken and fish.

The authors have produced a simple list to illustrate how much – or how little – it takes for different foods to contribute 1 kg of greenhouse gas emissions. On average this is:

  • 5.8 kg of onions (about 50 medium onions);
  • 3.5 kg of apples (about 20 medium apples);
  • 2.6 kg of oats;
  • 1 kg of lentils;
  • 1.2 kg of peanuts;
  • 800 mL of milk;
  • 290 g of salmon;
  • 290 g of eggs (about five small eggs);
  • 270 g of chicken;
  • 244 g of kangaroo;
  • 212 g of rabbit;
  • 131 g of Australian pork;
  • 44 g of Australian beef; and
  • 57 g of Australian lamb.

The aim of the study was to develop a dataset to support consumers and catering organisations in calculating the impact of their ingredients and menus. The authors had previously worked with a residential age care organisation to help reduce its greenhouse gas emissions, and found that the food served to residents contributed to a large portion of the environmental impact.

While they were aware of various strategies that could reduce this impact (such as having less red meat), to estimate the impact of a revised menu with some credibility was exceptionally difficult as the information was so dispersed. This started their attempt to understand more clearly the global warming potential of differing foods.

Verghese said the study was the largest and most comprehensive examination of its kind, providing the first global league table for fresh food.