Ever felt powerless in the face of major challenges such as global warming? Well, there's some good news: the way we cook our meals can actually make a big difference in the world's climate crisis, according to a new study in the UK. Up to 61% of food-related greenhouse gases come from home cooking, with different methods and appliances releasing different amounts of emissions.
Food (and cooking practices) are often left out of the food conversation, in part because data on household cooking practices are so scarce. Yet understanding climate change impacts of different food items from cradle to grave is vital for effectively reducing emissions. Food is estimated to emit 37% of global emissions.
Most studies estimate the climate change impact of food only up to the retail/purchase stages of the food supply chain, thus excluding preparation and cooking. However, the preparation of meat and vegetables can contribute up to 20% and 36% of total product emissions, respectively. In other words, what happens to the food after you buy it is a major contributor to emissions.
Researchers from several UK universities carried out a survey of 765 participants to gather data on cooking habits in households. Eleven different cooking methods, involving ten types of appliance, were assessed. Results showed on average cooking accounts for 6–61% of the total emission impacts for a given food. This changes according to the type of food. In the particular case of vegetables (namely, potatoes, carrots, cabbage, cauliflower, and onions), cooking accounts for up to 61% of their total emissions. Meanwhile, in the case of meat and fish, it represents 8–27% of their total emissions, the study showed (also due to the fact that meat's overall emissions are so big that cooking represents a relatively smaller part).
When it comes to ready-to-eat foods, the toasting of bread contributes 13% of the total emissions released. For semi-cooked or precooked foods, such as tofu, cooking accounts for up to 42% of their GHGs. Cooking canned baked beans, which are ready to eat after being heated up, represents 6% of their total emissions.
Even though cooking amounts to only 11% of meat's emissions, Cooking meat accounts for the highest overall emissions across the various foods in the UK. This is due to the long cooking times (>60 min) of oven roasting, which consumes the most energy among the different appliance types.
This might seem like a lot but there are actually several things we can all do to reduce our emissions from cooking, the study’s findings showed. Researchers found that emissions can be at least halved (in the case of toast) and reduced up to 16-fold (in the case of tofu) just by changing the cooking method used.
Considering the most common cooking appliances, ovens are the least sustainable due to comparatively long cooking times and high energy demand, while microwaves have the lowest overall impact. For vegetables, roasting in the oven comprises 53–78% of their total impact, while using the microwave would reduce emissions by up to 78%.
Using an electric grill is also a good alternative to toasting or grilling in the oven since it consumes half of the energy (and can use clean electric energy as well). For instance, grilling chicken in an electric grill releases 73% less GHG emissions than cooking in an oven. Electric grilling corresponds to 9% of the impact coming from the consumption stage, as opposed to 27% for oven grilling.
Cooking under pressure is also an efficient way of cooking meat, pulses, potatoes, and vegetables because the cooking time is substantially shortened. Using an electric pressure cooker as opposed to one that operates on the stovetop could further reduce emissions, since 50% less energy is required, the study found.
“We know GHG emissions from home cooking can be reduced by choosing which foods we eat and minimising cooking time and appliance use. Even combining a more environmentally friendly cooking method, such as using a microwave to part-cook food then roasting to finish in the oven, can cut our GHG emissions substantially,” said in a statement lead researcher Christian Reynolds.
The study was published in the journal Nature Food.