The rising level of carbon dioxide in the atmosphere means that crops are becoming less nutritious, and that change could lead to higher rates of malnutrition that predispose people to various diseases.

　　大气中二氧化碳含量的上升意味着作物中的营养成分变得越来越少，这种变化可能导致营养不良率上升，使人们更易患上各种疾病。

　　That conclusion comes from an analysis published Tuesday?in the journal PLOS Medicine, which also examined how the risk could be alleviated. In the end, cutting emissions, and not public health initiatives, may be the best response, according to the paper’s authors.

　　该结论源自周二在PLOS Medicine杂志上发表的一项论文，其作者在文末分析指出，最好的应对措施或许是减少碳排放量而非采取公共卫生举措。该杂志还研究了此种风险应该如何得到缓解。

　　Research has already shown that crops like wheat and rice produce lower levels of essential nutrients when exposed to higher levels of carbon dioxide, thanks to experiments that artificially increased CO2 concentrations in agricultural fields. While plants grew bigger, they also had lower concentrations of?minerals like iron and zinc.

　　研究已经表明，在一项人工增加农田中二氧化碳浓度的实验中，当小麦和水稻等作物暴露于此种环境中时，会产生较低水平的必需营养物质。随着植物不断生长，它们所含的铁和锌等矿物质浓度也会逐渐变低。

　　Fewer nutrients in crops means fewer nutrients in food. People who don’t get enough of the right nutrients are more likely to get sick. For instance, kids who don’t get enough zinc are more likely to contract diseases like malaria, pneumonia and diarrhea.

　　作物中的营养物质含量越少，食物中所含的营养物质相应也会减少。未能获得足量适当营养的人更容易生病。这就好比没有足够锌的孩子更容易感染疟疾，肺炎和腹泻等疾病。

　　But how many more people would get sick, and what could be done to keep that from happening?

　　但有多少人会因此罹患疾病，又可以采取何种措施有效阻止这种情况发生?

　　To answer this question, the researchers took the data we already know about carbon dioxide and crop nutrients and extended it to future CO2 concentrations. Atmospheric carbon dioxide concentrations are expected to rise from 400 parts per million to 550 ppm?by 2050.

　　为回答这一问题，研究人员选用了我们已获取的关于二氧化碳浓度和作物营养物质的数据，将其用于衡量未来二氧化碳浓度，并预计截至2050年，大气中的二氧化碳浓度将从400ppm升至550ppm。

　　Assuming people keep eating the same things, the researchers were able to predict how many more people would become nutrient-deficient as a result of their less nutritious diets. From there, the researchers then inferred changes in disease rates.

　　假定人们的膳食结构保持不变，研究人员能据此预测，会有多少人由于缺乏营养元素的饮食变得营养不良，从而推断出患病率的变化。

　　The results suggest that rising CO2will cost the world roughly 125 million disability-adjusted life years?– which are roughly equivalent to a year of healthy life – because of higher rates of disease between now and 2050.

　　结果表明，由于现今到2050年这段时间的患病率较高，二氧化碳浓度上升将使世界耗费大约1.25亿残疾调整生命年—这大致相当于健康生活的一年。

　　Most of the people affected would be in areas prone to malnutrition in Southeast Asia and Africa. Developed regions, such as Europe and North America, are unlikely to be heavily affected.

　　受影响的大多数人将来自于易于引起营养不良的东南亚和非洲地区。欧洲和北美等发达地区不太可能受到严重影响。

　　Next, the researchers simulated what would happen if countries took steps to mitigate the threat, such as reducing CO2 emissions in line with the Paris Agreement on climate, or passing out zinc pills to affected populations.

　　接下来，研究人员模拟了各国如若采取根据《巴黎气候协定》减少二氧化碳排放，或向受影响人群分发锌丸等措施减弱这种威胁后可能会出现的情况。

　　The researchers found that roughly half of the added disease burden could be avoided if CO2 levels were cut to levels stipulated by the Paris Agreement—480 ppm. But public health initiatives, like iron distribution or malaria mitigation, would only reduce the problem by a 20 percent.

　　研究人员发现，如果将二氧化碳浓度降低到《巴黎协定》规定的480 ppm水平，可以避免大约一半的新增疾病负担。但实施诸如分发铁金属或缓解疟疾等公共卫生计划只会使问题减少20%。

　　Diets have changed dramatically?in places like China, where more people are eating meat, a better source of iron than most plant-based foods. Additionally, Myers notes that some crop varieties appear resistant to the CO2-associated decrease in nutrition, and those varieties could provide the foundation for agricultural production in an increasingly CO2-rich atmosphere.

　　在像中国这样的地方，民众饮食已经产生了巨大变化：更多的人在吃肉，这是一种相比于大多数植物性食品而言，一种更好的获取铁元素的来源。此外，迈尔斯指出，一些作物品种似乎没有由二氧化碳引起的营养物质流失，因而在二氧化碳含量日益丰富的环境中，可以为农业生产提供基础。

　　The burden of addressing nutrient deficiency is not likely to fall on the people most responsible for the change. In the end, the study highlights how the habits of affluent countries trickle down to affect the world’s poor.

　　解决营养匮乏问题的负担不太可能落在对造成这一变化负有最大责任的人身上。最后，该研究强调了富裕国家民众的生活习惯是如何影响世界穷人的。

　　"It’s the wealthy people in the world who are emitting lots of carbon dioxide," Myers says. "Wealthy consumption patterns are putting the poorest, most vulnerable people in harm’s way."

　　“正是世界上的富人们在排放着大量的二氧化碳，”迈尔斯说。“富裕的消费模式正使最贫困，也是最脆弱的人群受到伤害。”