VOA常速英語：全球飲食影響氣候

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A new study says the growing popularity of the Western diet could help worsen climate change. As more people make meat a principal part of their diet, the authors say it will be very difficult to reduce greenhouse gas emissions.

The global population is forecast to grow to over nine billion by 2050. And as the population rises, so does the need for more food. The demand for meat is rising especially fast in many of the world’s emerging economies. The Western diet has become fashionable there.

Many studies have warned that the Western diet – filed with fat, sugar and salt – is triggering more non-communicable diseases -- diabetes, cardiovascular disease, cancer and obesity. But the new study published inNature Climate Change considers the health of the planet, not just the body.

Co-author Chris Gilligan, professor of mathematical biology at the University of Cambridge, said much of the study focuses on how greater food production will affect land use.

“Well, that’s going to be one of the major problems as we go forward. That has knock-on consequences then on conservation, on biodiversity, but also on use of land for other purposes. For organization, for example, for energy supply and how we manage water. How do we find enough land to produce the crops for crop growth – the crops that are then used to feed animals and also regions for rearing the animals?”

The study said using more land for food production carries a “high price.” Deforestation, for example, would result in greater carbon emissions.

“First of all, we think about where is that new land for agriculture going to come from? And a lot of it is going to come from pristine forests. So as you remove those forests, you’re removing trees which are very important traps for carbon dioxide. And in deforestation there’s an increase in greenhouse gas emissions,” he said.

Gilligan said greater food production also will result in more methane being released into the atmosphere.

“Increasing livestock production also involves a large amount of greenhouse gas production from the animals themselves.”

Methane would also be released through the use of manure as fertilizer. The study says increased deforestation, fertilizer use and methane from livestock “are likely to cause greenhouse gas emissions from food production to increase by nearly 80-percent.”

Gilligan said that what people choose to eat is a major driver behind greenhouse gas emissions.

“For many people meat does taste exciting. It tastes different. [You] can do lots of things with it in a culinary way, as one can with vegetables, of course. But nevertheless there is an attraction there – an attraction in saying, well, yes, I eat a lot more meat than I used to.”

The study also said that “food production is a main driver of biodiversity loss…and pollution.”

The Cambridge professor added that reducing greenhouse gas emissions could involve persuading people to eat differently – but adds it won’t be easy.

“There may be economic means by which this is done, for example, through a carbon tax. But that’s a punitive measure and may perhaps be necessary. More preferable, however, is the notion of the nudge approach to behavior. So, how do you make it attractive for people to change their dietary behavior? That is about publicity about the health advantages and hoping that that really induces people to change what they do,” he said.

Reducing waste during food production, he said, would go a long way toward lowering pollution.

“There’s a huge amount of loss of material through waste in developing countries pre-harvest – and in developed countries, sadly, post-harvest. Were we able to move to a reduction in, for example, waste, that could have a significant reduction in the amount of greenhouse gas emission,” he said.

The U.N. Environment Program estimated one-third of the food produced for human consumption every year gets lost or wasted. That’s about

1.3 billion tons of food that nobody gets to eat. The UNEP reported in the U.S. alone 30 percent of all food is thrown away.

The study goes on to say the Western diet is characterized by an “excessive consumption of food.” Researchers came up with -- what they call -- an “average” balanced diet that would reduce pressure on the environment. It includes “two 85-gram portions of red meat and five eggs per week”, along with a daily portion of poultry.

They said it’s not about being vegetarian. It’s about eating sensibly, while protecting the environment.