新闻来自nbc news。
原文链接：
https://www.nbcnews.com/mach/science/climate-change-could-affect-human-evolution-here-s-how-ncna907276
编者注：
现在的科学家，也总想搞大新闻。
作者Scott Solomon在莱斯大学教授生态、进化和科学传播，是“未来人类：我们持续进化的科学内因”一书的作者。
中文部分为编者翻译，编者英语四级水平，如有错误，纯属必然，欢迎指正，共同进步。
As climate change brings rising temperatures, droughts, shifting patterns of precipitation and longer growing seasons, plants and animals are evolving to keep pace.
随着气候变化带来气温上升、干旱、降水模式变化以及生长季节的延长，植物和动物正在不断进化以进行适应。
Biologists have observed squirrels and salmon developing at an accelerated pace, causing them to reproduce at a younger age. Earlier summers have caused some flowers to bloom earlier in the year. And corals are forging new relationships with microscopic algae to survive in warmer, more acidic seas.
生物学家观察到松鼠和鲑鱼的发育速度加快，使它们繁殖的年龄更低。过早到来的夏天使得一些鲜花开放更早，珊瑚也在与微型藻类建立新的关系，以便在更加温暖、酸性更强的海水中生存。
As the planet continues to warm, evolutionary changes are expected in other species as well — including Homo sapiens. Climate change will alter the internal workings of our bodies in subtle but significant ways and will likely cause a noticeable shift in our appearance.
随着地球的继续变暖，预计其他物种也会发生进化行为，这其中当然也包括人类。气候变化将以微妙而重要的方式改变我们身体的内部运作，并可能导致我们的外表发生明显变化。
INSIDE THE BODY
身体内部变化
A warmer climate means malaria, West Nile virus and other diseases long confined primarily to the tropics will spread into temperate zones. As a result, people living in the U.S. and other developed nations will be exposed to these illnesses, and our immune systems will be forced to evolve new defenses. That, in turn, could cause other, noninfectious diseases.
气候变暖意味着疟疾、西尼罗河病毒和其他长期局限于热带地区的疾病将蔓延到温带地区。结果会是，生活在美国和其他发达国家的人们将面临这些疾病，我们的免疫系统将被迫发展出新的防御系统。相反，这可能会导致其他非传染性疾病。
Two blood disorders — sickle cell and thalassemia — arose and continue to exist because they have a beneficial side effect: resistance to malaria. Such disorders, or new ones, may soon appear if malaria moves into populated areas of North America, East Asia and Europe.
两种血液疾病 - 镰状细胞和地中海贫血 - 将出现并继续存在，因为它们具有有益的副作用：抗疟疾。如果疟疾进入北美、东亚和欧洲的人口稠密地区，这种疾病或新的疾病可能很快出现。
Similarly, our digestive systems will evolve in response to shifts in food availability — where crops and livestock can be cultivated. The ability to digest milk in adulthood evolved among groups in the Middle East and North Africa that began raising cattle. Future generations may evolve better abilities to tolerate sugar or fat.
同样，我们的消化系统将随着食物供应的变化而发展，特别是在农畜产地。在开始饲养奶牛的中东和北非地区，成年人消化牛奶的能力发生变化，其后代可能会发展出更好的耐受糖或脂肪的能力。
Changing diets will also trigger changes in our microbiomes — the bacteria and other microorganisms that live in our guts and help to keep us healthy. Vegetarians tend to harbor a different mix of bacteria than meat eaters, and these changes could be exaggerated if prolonged droughts make it too costly to raise livestock for meat.
改变饮食也会引发我们体内微生物群体的变化，这些细菌和其他微生物存在于我们的内脏中，有助于保持我们的健康。素食者往往含有不同于肉食者的微生物群体，如果长期干旱导致饲养牲畜成本太高，这些变化可能会被放大。
EXTERNAL CHANGES
外貌变化
While these changes will be of enormous interest to biologists, they will be largely invisible. But as we change on the inside, we’ll also be changing on the outside. Evidence suggests that a warming planet could melt away differences between human races — or population groups, as scientists more accurately call them.
虽然上述这些变化对生物学家来说非常重要，但它们在很大程度上是不可见的。但随着我们内部的改变，我们的外貌也会改变。有证据表明，一个变暖的地球可以消除人类种族差异，准确的说是人口群体之间的差异。
The reason why climate change could reduce racial differences is that it will trigger massive migrations. In recent decades the world has become more urbanized, with people moving into large cities in coastal areas. But as polar ice melts and sea levels rise, large numbers of people will be forced to flee the coasts. And as droughts become more common and more severe, people living in more arid areas will have to move to places with more reliable sources of water.
气候变化可以减少种族差异的原因是它会引发大规模的人口迁移。近几十年来，世界城市化发展迅速，人口流沿海地区的大城市。但随着极地冰层融化和海平面上升，大量人口将被迫离开海岸。随着干旱变得更加普遍和严重，生活在干旱地区的人们将不得不搬到拥有固定水源的地方。
These migrations will erode the geographic barriers that once separated human populations. In fact, this process is already underway. As of 2017, 258 million people were living in a country other than the one they were born in — an increase of 49 percent since 2000, according to a report from the United Nations. A World Bank report released in March predicts that climate change will cause 140 million people to migrate by 2050, with those now living in sub-Saharan Africa, South Asia and Latin America especially likely to migrate.
这些迁移将穿越曾经造成人口分离的地理屏障。事实上，这个过程已经在进行之中。根据联合国的一份报告，截至2017年，有2.58亿人生活在他们出生的国家以外，自2000年以来增加了49％。世界银行3月份发布的一份报告预测，到2050年，气候变化将导致1.4亿的人口迁移，现在生活在撒哈拉以南非洲、南亚和拉丁美洲的人群尤其可能迁移。
One consequence of large-scale migrations is what biologists call gene flow, a type of evolution caused by the blending of genes between populations. When people from different populations mate and reproduce, their genes intermingle in their children. That can lead to combinations of traits not seen in either parent or in the populations they come from — like the dark skin and blue eyes of Cape Verde islanders, the result of interbreeding between Portuguese and West Africans.
大规模迁移的一个后果是生物学家所谓的基因流动，这是一种由种群间基因混合引起的进化。当来自不同人群的人婚配时，他们的基因就会在他们的孩子身上融合。这可能出现在他们父母或他们来自的人群中没有的特征组合，比如佛得角岛民的黑皮肤和蓝眼睛，就是葡萄牙人和西非人之间混血的结果。
SHIFTING SKIN COLOR
改变皮肤颜色
One of the most obvious effects of gene flow may be greater similarity in skin color.
基因流动最明显的影响之一可能是使人类的肤色更加相似。
Skin color differences came about a result of natural selection in different human populations. The pigment eumelanin makes skin darker, which helps protect against harsh sunlight. But too much eumelanin can make it hard for the body to produce vitamin D, which is needed to build healthy bones. So over many thousands of years, human populations evolved varying levels of skin pigmentation as they spread across the globe, with natural selection balancing the cost of having too much eumelanin (which can indirectly cause bone deformities) versus having too little (which can lead to cancer and birth defects).
皮肤颜色差异是由于不同人群中的自然选择造成的。真黑素使皮肤更暗，有助于抵御强烈的阳光。但过多的真黑素可能会使身体难以产生维生素D，维生素D是建立健康骨骼所必需的。因此，在数千年的时间里，人类在全球范围内进化出不同程度的皮肤色素沉着，自然选择平衡了过多的真黑素（可能间接导致骨骼畸形）与过少（可能导致癌症和先天缺陷）的影响。
As a result, skin color came to closely match the intensity of sunlight in different regions — darker near the equator and lighter near the poles.
这样的结果是，肤色与不同区域的阳光强度非常相关，赤道附近较暗，而极地附近较浅。
But in today’s world, with sunscreen and vitamin supplements, natural selection is less relevant to ongoing changes in human skin pigmentation than gene flow. Because skin color is controlled by many genes, parents whose skin color differs tend to have children with intermediate skin tones. And so in five to 10 generations (125 to 250 years), we may see fewer people with dark skin or pale skin and more with a brown or olive complexion. Having both dark skin and light eyes may become more common.
但在今天的世界中，人们使用防晒霜和服用维生素，自然选择与人体皮肤色素的关系不如基因的影响强大。由于皮肤颜色受许多基因控制，因此肤色不同的父母往往会生出具有中度肤色的儿童。因此，在5至10代（125至250年）中，我们可能会看到更少皮肤较黑或皮肤苍白的人，而是更多棕色或橄榄色。同时拥有深色皮肤和浅色眼睛的人可能会变得更加常见。
Blending of races is already well underway in ethnically diverse countries like Brazil, Singapore and the U.S. A Pew report from 2017 found that the number of multiracial births in the U.S. rose from 1 percent in 1970 to 10 percent in 2013. And the increase will continue — the multiracial population is projected to grow by 174 percent over the next four decades.
在巴西、新加坡和美国这些种族多样化的国家，种族混合已经在进行中。2017年的皮尤报告发现，美国的混血新生儿数量从1970年的1％上升到2013年的10％。这一增长将继续，预计四十年后，混血人口将增长174％。
The bottom line? As people around the world become more physically similar to one another, it's possible that racism might slowly fade.
底线？随着世界各地的人们在身体上越来越相似，种族主义可能会逐渐消失。
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