A third of all food produced worldwide is never eaten. But how easy is it to reduce our food waste? Two students have found out.

“That's not a very pleasant smell,” says student Helen Chigwende, standing with the entire contents of her household food waste bin laid out before her. Helen and one of her house-mates, Will Smith, want to learn how to live a more sustainable(可持续的) lifestyle, so they need to understand their habits. That means searching their leftovers or food that has been sent straight to the bin without being touched. They soon find out how much of their food waste could have been avoided. “We've got a piece of sandwich meat that doesn't even seem to be eaten,” Will says, looking at what sill-eatable food he could save. It is formed into a pile of “avoidable” waste, which soon becomes the “unavoidable” things.

“One of the reasons why we end up with a lot of food waste is that food isn't stored properly,” explained Dr Woolley. Sometimes it is placed in an area of the fridge or cupboard where it is not easily noticeable, so it gets left and not eaten in time. There are also two other tips in reducing food waste. “The first is planning,” he says. “Write a shopping list to make sure you're not repeating things you've already got. The second is preparation. Cook the right amount for the people that are going to eat.”

Back at the student house, Helen and Will are cooking vegetarian food to ensure a sustainable lifestyle. The long term test of whether they can keep up with their dietary prices and reduce food waste is yet to come. But both are devoted to making a positive change now. Despite being a “picky cater”, Helen says a week of sticking to health has not been too diff-cult. “It's just about finding things you'll enjoy eating.”

Marco Springmann and his colleagues, at the Oxford Martin School's Future of Food Programme, built computer models that predicted what would happen if everyone became vegetarian by 2050. The results indicate that if the world went vegan, the greenhouse gas emissions declines would be around 70%.

In the US, for example, an average family of four emits more greenhouse gases because of the meal they eat than from driving two cars——but it is cars, not steaks, that regularly come up in discussions about global warming.

Food, especially livestock, also takes up a lot of room. 68% of agricultural land in the world is used for livestock. When these lands become grasslands and forests, they would capture carbon dioxide and further ease climate change.

However, if the whole world went vegan, there would be negative effects too. First, it is necessary to keep livestock for environmental purposes. "I'm sitting here in Scotland where the Highlands' environment is very man-made and based largely on grazing by sheep," says Peter Alexander, a researcher in socio-ecological systems modeling at the University of Edinburgh. "If we took all the sheep away, the environment would look different and there would be a potential negative impact on biodiversity. "

Plus, meat is an important part of history , tradition and cultural identity. Numerous groups around the world give livestock gifts at weddings, celebratory dinners such as Christmas with turkey or roast beef.

And nowadays, moderation in meal-eating's frequency and portion size is key to solving these conflicts. "Certain changes would encourage us to make healthier and more environmentally friendly dietary decisions," says Springmann, "like putting a higher price lag on meat and making fresh fruits and vegetables cheaper. "

In fact, clear solutions already exist for reducing greenhouse gas emissions from the livestock industry. What is lacking is the will to implement those changes.

How To Eat Better for the Planet

You are environmentally conscious and hungry. Here are answers to all your eco-friendly food questions.

Does what I eat have an effect on climate change?

Yes. 【小题1】. About one quarter of the planet-warming greenhouse gases are generated by humans each year. That includes raising and harvesting all the plants, animals, and animal products we eat, as well as processing, packaging, and shipping food to markets all over the world.

【小题2】?

When forests are cleared to make room for farms and cattle, large stores of carbon are released into the atmosphere, which heats up the planet. Also, fossil (化石) fuels are used to operate farm machinery and ship food around the globe, all of which generate emissions (排放). Which foods have the largest impact?

【小题3】. Cattle accounts for roughly the same amount of emissions as all the cars, trucks, airplanes, and ships in the world today, while plant-based foods like beans and grains tend to have the smallest effect. Pork, chicken, and eggs are somewhere in the middle.

Why does meat have such a big effect on the climate?

It’s often more efficient to grow crops for humans to eat than it is to grow crops for animals to eat and then turn those animals into food for humans. A conclusion was reached by the United Nations Food and Agriculture Organization in 2017. 【小题4】.

Is there a simple food choice I can make that would reduce my climate footprint?

Consuming less red meat and dairy will typically have the biggest effect for most people in wealthy countries. A number of studies have concluded that people who eat a meat-heavy diet could reduce their food-related footprint by one third or more by moving to a vegetarian diet. 【小题5】. If you don’t want to go that far, just eating less meat and dairy can reduce emissions.