好英语网如果全世界都突然改吃素会怎样？
People become vegetarians for a variety of reasons. Some do it to alleviate animal suffering, others because they want to pursue a healthier lifestyle. Still others are fans of sustainability or wish to reduce greenhouse gas emissions.
人们成为素食主义者的原因有很多。有些是为了减轻动物的痛苦，还有些人是希望追求更健康的生活方式。此外，也有人支持可持续发展，或者想减少温室气体排放。
No matter how much their carnivorous friends might deny it, vegetarians have a point: cutting out meat delivers multiple benefits. And the more who make the switch, the more those perks would manifest on a global scale.
不管人们怎么说，素食主义者都坚定地认为，不吃肉的好处多多。并且加入素食阵营的人越多，这些好处就更能在全球遍及开来。
But if everyone became a committed vegetarian, there would be serious drawbacks for millions, if not billions, of people.
但如果全世界所有人都变成了坚定的素食主义者，至少有数百万人的利益会受到严重影响。
“It’s a tale of two worlds, really,” says Andrew Jarvis of Colombia’s International Centre for Tropical Agriculture. “In developed countries, vegetarianism would bring all sorts of environmental and health benefits. But in developing countries there would be negative effects in terms of poverty.”
“我们分处两个不同的世界，”哥伦比亚热带农业国际中心的安德鲁·贾维斯（Andrew Jarvis）说道，“在发达国家，素食主义会带来各种环境和健康方面的好处。但在发展中国家，这则会进一步加剧贫困程度。”
Jarvis and other experts at the centre hypothesised what might happen if meat dropped off the planet’s menu overnight.
贾维斯和该中心的其它专家进行了一次假设，看看如果全世界的人在一夜之间突然都不吃肉了，会发生什么情况。
First, they examined climate change. Food production accounts for one-quarter to one-third of all anthropogenic greenhouse gas emissions worldwide, and the brunt of responsibility for those numbers falls to the livestock industry. Despite this, how our dietary choices affect climate change is often underestimated. In the US, for example, an average family of four emits more greenhouse gases because of the meat they eat than from driving two cars – but it is cars, not steaks, that regularly come up in discussions about global warming.
他们首先研究了气候变化。在全球人类活动产生的温室气体中，食品生产行业的温室气体排放量占了四分之一到三分之一，这其中大部分都来自畜牧业。除此之外，我们还常常低估饮食习惯对气候变化的影响。以美国为例，一个四口之家由于吃肉排放的温室气体比开两辆车排放的气体还要多。但在讨论全球变暖问题时，人们往往只会谈到汽车，而忽视了这点。
“Most people don’t think of the consequences of food on climate change,” says Tim Benton, a food security expert at the University of Leeds. “But just eating a little less meat right now might make things a whole lot better for our children and grandchildren.”
“大多数人根本不会考虑食物对气候变化的影响，”英国利兹大学的粮食安全专家蒂姆·本顿（Tim Benton）指出，“但事实上，只要我们少吃哪怕一点点肉，就能大大造福我们的子孙后代。”
Marco Springmann, a research fellow at the Oxford Martin School’s Future of Food programme, tried to quantify just how much better: he and his colleagues built computer models that predicted what would happen if everyone became vegetarian by 2050. The results indicate that – largely thanks to the elimination of red meat – food-related emissions would drop by about 60%. If the world went vegan instead, emissions declines would be around 70%.
牛津大学未来食物项目的研究员马可·斯普林曼（Marco Springmann）试图量化素食的益处。他和同事一起建立了相关的计算机模型，可以预测出如果所有人在2050年前都变成了素食主义者，会发生什么情况。结果显示，由于人们不再食用红肉，食物生产相关的排放量减少了约60%。如果全世界的人都变成了严格的素食主义者，温室气体排放量将减少70%。
“When looking at what would be in line with avoiding dangerous levels of climate change, we found that you could only stabilise the ratio of food-related emissions to all emissions if everyone adopted a plant-based diet,” Springmann says. “That scenario is not very realistic – but it highlights the importance that food-related emissions will play in the future.”
“我们想知道，要想避免气候变化达到危险程度，我们还需要做些什么。结果发现，只有当所有人都以素食为主，才能使食物相关的温室气体排放量在总体排放量中的占比维持在一个稳定的水平，”斯普林曼说道，“这种设想不太现实，但它体现了食物相关的温室气体排放在未来所占据的重要地位。”
Food, especially livestock, also takes up a lot of room – a source of both greenhouse gas emissions due to land conversion and of biodiversity loss. Of the world’s approximately five billion hectares (12 billion acres) of agricultural land, 68% is used for livestock.
食物——尤其是牲畜——占据了大量空间。土地的转换和生物多样性的丧失，也是温室气体排放增加的重要原因。全世界的农业用地约为50亿公顷，其中68%都用于牲畜养殖。
Should we all go vegetarian, ideally we would dedicate at least 80% of that pastureland to the restoration of grasslands and forests, which would capture carbon and further alleviate climate change. Converting former pastures to native habitats would likely also be a boon to biodiversity, including for large herbivores such as buffalo that were pushed out for cattle, as well as for predators like wolves that are often killed in retaliation for attacking livestock.
假如我们都变成了素食主义者，在理想情况下，我们至少能使80%的牧场变回草原和森林，植物将吸收更多的二氧化碳，进一步减缓气候变化。此前为了养殖牲畜，人们曾驱逐过很多大型食草动物，比如野牛。此外为了保护牲畜，人们还杀死了一些狼之类的食肉动物。因此，把牧场变为天然栖息地，还可以增加生物多样性。
The remaining 10 to 20% of former pastureland could be used for growing more crops to fill gaps in the food supply. Though a relatively small increase in agricultural land, this would more than make up for the loss of meat because one-third of the land currently used for crops is dedicated to producing food for livestock – not for humans.
剩下的10%到20%的牧场可以用来生产更多的庄稼，填补食物供应的空缺。虽然农业用地相对来说只增加了很少一部分，但这对补足膳食来说绰绰有余。因为目前用来生产庄稼的土地中，大约有三分之一是用来种植牲畜食用的饲料的，而非为人食用。
Both environmental restoration and conversion to plant-based agriculture would require planning and investment, however, given than pasturelands tend to be highly degraded. “You couldn’t just take cows off the land and expect it to become a primary forest again on its own,” Jarvis says.
不过，由于很多牧场都已经严重退化，环境重建和农业转型都需要大量的筹备工作和财力资助。“不可能牛群一走，牧场自己就会变回之前的原始森林，”贾维斯说。
Carnivorous careers
转业问题
People formerly engaged in the livestock industry would also need assistance transitioning to a new career, whether in agriculture, helping with reforestation or producing bioenergy from crop byproducts currently used as livestock feed.
我们还需要帮助那些从事畜牧工作的人转移到别的行业中去，如从事农业、帮助森林重建、或利用庄稼副产品制造生物能源等等。
Some farmers could also be paid to keep livestock for environmental purposes. “I’m sitting here in Scotland where the Highlands environment is very manmade and based largely on grazing by sheep,” says Peter Alexander, a researcher in socio-ecological systems modelling 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.”
我们还可能会出于环境原因，付钱让农民养殖牲畜。“苏格兰的高地环境很大一部分是人为塑造的，主要以绵羊放牧业为基础，”爱丁堡大学一名社会生态系统建模方面的研究人员彼得·亚历山大（Peter Alexander）指出，“如果我们不再养殖绵羊，这里的环境就会发生变化，可能会对生物多样性造成负面影响。”
Should we fail to provide clear career alternatives and subsidies for former livestock-related employees, meanwhile, we would probably face significant unemployment and social upheaval – especially in rural communities with close ties to the industry.
如果我们没能为这些人提供清晰的转业选择并为不再从事畜牧业的雇员提供补贴，我们就可能面临严重的失业和社会动乱，特别是在和牲畜养殖业联结紧密的乡村地区。
“There are over 3.5 billion domestic ruminants on earth, and tens of billions of chickens produced and killed each year for food,” says Ben Phalan, who researches the balance between food demand and biodiversity at the University of Cambridge. “We’d be talking about a huge amount of economic disruption.”
“世界上有超过35亿头反刍动物（如牛等）。此外，人类每年蓄养数百亿只鸡，宰杀后变成人的食物，”本·帕兰（Ben Phalan）说。他在剑桥大学研究食物供应与生物多样性之间的平衡问题，“这会对经济造成极大的影响。”
But even the best-laid plans probably wouldn’t be able to offer alternative livelihoods for everyone. Around one-third of the world’s land is composed of arid and semi-arid rangeland that can only support animal agriculture. In the past, when people have attempted to convert parts of the Sahel – a massive east-to-west strip of Africa located south of the Sahara and north of the equator – from livestock pasture to croplands, desertification and loss of productivity have ensued. “Without livestock, life in certain environments would likely become impossible for some people,” Phalan says. That especially includes nomadic groups such as the Mongols and Berbers who, stripped of their livestock, would have to settle permanently in cities or towns – likely losing their cultural identity in the process.
但就算计划筹备得再完善，我们也不可能帮助所有人找到替代的工作。全世界约有三分之一的土地是干燥和半干燥的牧场土地，只能用来养殖牲畜。过去人们曾试图把非洲撒黑尔地区（Sahel ，位于撒哈拉沙漠南部和赤道之间）的牧场转变为庄稼地，但沙漠化接踵而至，生产力也大幅下降。“没有了牲畜，有些环境就可能不适宜人类居住了，”帕兰说道。尤其是游牧民族，比如蒙古人和柏柏尔人，他们如果没有了牲畜，就只能在城镇中定居下来——很可能就此失去自己的文化身份。
Plus, even those whose entire livelihoods do not depend on livestock would stand to suffer. 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 centre around turkey or roast beef, and meat-based dishes are emblematic of certain regions and people. “The cultural impact of completely giving up meat would be very big, which is why efforts to reduce meat consumption have often faltered,” Phalan says.
此外，即使是那些不完全靠牲畜为生的人，日子也会变得很难熬。无论是在历史上、传统上还是文化认同感中，肉都是一个重要部分。全世界有很多种族都会在婚礼上和节庆日送上牲畜作为礼物，例如，圣诞节的核心便是火鸡或烤牛肉。“如果完全摒弃了肉，这将对文化造成巨大的冲击，因此有很多试图减少肉类食用量的努力都遭遇失败。”帕兰说道。
The effect on health is mixed, too. Springmann’s computer model study showed that, should everyone go vegetarian by 2050, we would see a global mortality reduction of 6-10%, thanks to a lessening of coronary heart disease, diabetes, stroke and some cancers. Eliminating red meat accounts for half of that decline, while the remaining benefits are thanks to scaling back the number of calories people consume and increasing the amount of fruit and vegetables they eat. A worldwide vegan diet would further amplify these benefits: global vegetarianism would stave off about 7 million deaths per year, while total veganism would knock that estimate up to 8 million. Fewer people suffering from food-related chronic illnesses would also mean a reduction in medical bills, saving about 2-3% of global gross domestic product.
不吃肉对健康的影响也很复杂。斯普林曼的计算机模型显示，假如到了2050年，所有人都成了素食主义者，那么心血管疾病、糖尿病、中风和部分癌症将减少，由此全球死亡率将降低6%到10%。其中有一半的功劳当属红肉的退场，而剩下的则是因为人们摄入的热量减少，食用的水果和蔬菜却有所增多。如果全世界都施行严格素食主义，带来的好处将更加明显：如果只是普通素食主义，每年死亡人数将减少700万；而如果施行严格素食主义，每年死亡人数最多会减少800万。患有食物相关的慢性病的人数也将减少，这意味着人们可以节省医疗开支，节省下来的成本相当于全球GDP的2%至3%。
But realising these projected benefits would require replacing meat with nutritionally appropriate substitutes. Animal products contain more nutrients per calorie than vegetarian staples like grains and rice, so choosing the right replacement would be important, especially for the world’s estimated two billion-plus undernourished people. “Going vegetarian globally could create a health crisis in the developing world, because where would the micronutrients come from?” Benton says.
但要想实现这些益处，我们必须寻找与肉类营养相当的替代品。每单位卡路里的动物食品中所含的营养比素食主食（如谷物和米饭等）要多，因此我们必须找到合适的替代品。据估计，世界上约有20亿人处于营养不良状态，因此找到合适的替代品对于他们来说尤为重要。“如果所有人都变成了素食主义者，这将在发展中国家引发健康危机，因为他们将无从获得微量元素，”本顿说。
All in moderation
节制最关键
But fortunately, the entire world doesn’t need to convert to vegetarianism or veganism to reap many of the benefits while limiting the repercussions.
不过幸运的是，我们不需要全世界人都变成素食主义者，也能实现很多好处，同时减少相关的消极影响。
Instead, moderation in meat-eating’s frequency and portion size is key. One study found that simply conforming to the World Health Organization’s dietary recommendations would bring the UK’s greenhouse gas emissions down by 17% – a figure that would drop by an additional 40% should citizens further avoid animal products and processed snacks. “These are dietary changes that consumers would barely notice, like having a just-slightly-smaller piece of meat,” Jarvis says. “It’s not this either-or, vegetarian-or-carnivore scenario.”
我们应当节制食用肉类的频率和数量。一项研究发现，只要全英国人遵循世界卫生组织（WHO）给出的营养建议，英国的温室气体排放量就能减少17%。而如果人们进一步减少购买动物制品和加工零食，这一数字还能再减少40%。“消费者几乎不会注意到自己的食物发生了什么变化，其实也就是吃的那块肉稍微变小了一点而已，”贾维斯说道，“这并不是素食和肉食只能二选一的问题。”
Certain changes to the food system also would encourage us all to make healthier and more environmentally-friendly dietary decisions, says Springmann – like putting a higher price tag on meat and making fresh fruits and vegetables cheaper and more widely available. Addressing inefficiency would also help: thanks to food loss, waste and overeating, fewer than 50% of the calories currently produced are actually used effectively.
斯普林曼表示，食物体系的变化还能鼓励我们培养更加健康、对环境更加友好的饮食习惯。这些变化包括抬高肉类定价、降低新鲜蔬菜水果的价格、扩大销售范围等等。提高利用率也能起到一定的作用，由于浪费和饮食过度等问题，如今生产的全部食物能量中，只有不到一半的能量得到了有效利用。
“There is a way to have low productivity systems that are high in animal and environmental welfare – as well as profitable – because they’re producing meat as a treat rather than a daily staple,” Benton says. “In this situation, farmers get the exact same income. They’re just growing animals in a completely different way.”
“我们可以减少该行业的产量，但使其变得对动物和环境更加友好，利润也更高，因为肉变成了一道珍馐，而非日常菜肴，”本顿说道，“这样一来，农民的收入就可以保持不变，只不过换了一种养殖牲畜的方式而已。”
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.
事实上，要想减少牲畜养殖业的温室气体排放量，我们已经有了清晰明了的解决方法。我们缺少的，只是实施这些变化的决心而已。