聯合國:2100年全球人口將達到109億大綱

The world's Population could swell to 10.9 billion by the end of the century, a new United Nations analysis found, raising concerns that adding more than 3 billion people to the planet could further deplete natural resources and accelerate global warming.
聯合國最新分析發現，到本世紀末，世界人口可能會增至109億。人們擔心，地球上增加30多億人口可能會進一步耗盡自然資源，加速全球變暖。

The increase, up from the current count of 7.7 billion people, is expected despite a continued decline in the global fertility rate, which has fallen from 3.2 births per woman in 1990 to 2.5 births per woman this year. Experts say the global fertility rate will continue to decline, but the world’s overall population will still rise, hitting 9.7 billion by 2050.
儘管全球生育率持續下降，但預計屆時這一數字仍將遠超目前的77億人口。全球生育率從1990年的3.2下降到今年的2.5。專家表示，全球生育率將繼續下降，但世界總人口仍將增長，到2050年達到97億。

The new report predicts slower population growth than the UN's last assessment, released in 2017. That estimate projected that the world population would reach a staggering 11.2 billion by the end of the century. The revised figures reflect the downward trend in the globalfertility rate, which means the populations of more countries are shrinking.
這份新報告預測的全球人口增長速度低於聯合國2017年發佈的上一次評估。此前的評估預計，到本世紀末世界人口將達到驚人的112億。修正後的數據反映出全球生育率下降的趨勢，這意味着更多國家的人口正在減少。

The fastest growth, according to the new report, is most likely to occur in sub-Saharan Africa, which is expected to double its population in the next 30 years. The report also projected that India would become the world's most populous country by about 2027, surpassing China. Over the next 30 years, 54 other countries are expected to see population declines, including Lithuania, Bulgaria, Ukraine and Japan.
根據這份新報告，人口增長最快的地區最有可能出現在撒哈拉以南非洲，預計在未來30年，該地區的人口將增加一倍。報告還預測，到2027年，印度將超過中國，成爲世界上人口最多的國家。在未來30年，預計其他54個國家的人口將出現下降，包括立陶宛、保加利亞、烏克蘭和日本。

The United States is estimated to grow from 329 million people in 2019 to 434 million people by the end of the century, with most of that projected increase owing to migration.
據估計，到本世紀末，美國人口將從2019年的3.29億增長到4.34億，增加的大部分人口將來自移民。

According to the UN, many of the fastest-growing regions are among the poorest, which could exacerbate issues of hunger and displacement.
根據聯合國的數據，許多人口增長最快的地區都屬於最貧窮的地區，這可能會加劇飢餓和流離失所的問題。

Scientists are also concerned about the effect of population growth on climate change. As the global population increases, so will humanity's footprint on the planet.
科學家們還擔心人口增長對氣候變化的影響。隨着全球人口的增長，人類將影響地球上更廣泛的區域。

"Our impact on the climate is tied up with population in lots of different ways — what resources people are using, how much industrial production is going on, how much energy is needed for heating, cooling and transportation," Amy Snover, director of the University of Washington's Climate Impacts Group, said. "All of these things affect greenhouse gas emissions, so the more people we have and the more resources we use, the harder it will be to cope with the risks and impacts of climate change."
華盛頓大學氣候影響小組主任艾米·斯諾弗說：“我們對氣候的影響在很多方面都與人口息息相關。人們使用了什麼資源，在進行多少工業生產，需要多少能源用於取暖、製冷和運輸。所有這些都影響到溫室氣體的排放，所以人口越多，使用的資源越多，就越難以應對氣候變化的風險和影響。”

But population growth is just one of the factors driving climate change. Consumption habits also matter, and they're far from uniform across countries.
但人口增長只是推動氣候變化的因素之一。消費習慣也很重要，各國民衆的消費習慣也不盡相同。

"There's a massive disconnect between where the most population growth is happening and where the greatest consumption is happening," said Corey Bradshaw, director of the Global Ecology Laboratory at Flinders University in Australia. In other words, the average person's lifestyle in the US is more detrimental to the environment than the average person's in sub-Saharan Africa. That means rapid population growth in Africa won't be as damaging to the environment as a similar population increase would be in the US.
澳大利亞弗林德斯大學全球生態實驗室主任科裏·布拉德肖說：“人口增長最快的地方和消費最多的地方之間存在着巨大的脫節。”換句話說，美國普通人的生活方式比撒哈拉以南非洲普通人的生活方式對環境的危害更大。這意味着非洲人口的快速增長對環境的破壞不會像美國人口增長帶來的影響那樣嚴重。

In some regions, the increasing population means more people will be vulnerable to rising seas, extreme weather and the spread of infectious diseases, which can all be intensified by climate change.
在一些地區，人口增長意味着更多的人將容易受到海平面上升、極端天氣和傳染病傳播的影響，而這些都可能因氣候變化而加劇。

"People in the least-developed countries already tend to be at higher risk of climate change, so depending on how population growth unfolds across the globe, there's going to be more people in hazardous areas," Snover said.
斯諾弗說：“最不發達國家的人民已經面臨着更高的氣候變化風險，因此，將有越來越多的人生活在危險地區，這取決於全球人口增長的趨勢。”

She added that one of her biggest concerns is whether the planet will have enough resources to meet people's basic needs. Population growth, combined with climate change, could strain agriculture and access to clean drinking water even more.
她補充說，一個最大的擔憂是地球上是否有足夠的資源來滿足人們的基本需求。人口增長加之氣候變化可能會給農業生產和獲取清潔飲用水帶來更多困難。

"These are all big things," Snover said. "We don't have the luxury of picking only one problem to focus on because they're all coming and they're all coming together."
斯諾弗說：“這些都很重要。我們不能只關注一個問題，因爲這些問題都出現了，而且是一起出現。”

Scientists say it's difficult to know whether there's a limit to the number of people the planet can sustain — or when we could be approaching it. Still, according to Bradshaw, the 7.7 billion people who inhabit Earth now may already be pushing the planet to a breaking point.
科學家表示，很難知道地球能承受的人口上限，或者何時會接近上限。不過，據布拉德肖說，現在居住在地球上的77億人可能已經把地球推向了崩潰的邊緣。

"Even if we maintained the current status quo and not a single other carbon molecule was released because of human activity," he said, "we'd still see the effects of climate change for at least 300 years from just the emissions that are already in the system."
他說：“即使我們維持目前的現狀，不再因爲人類活動而有更多的碳排放，但由於生態系統中已經存在的碳排放，在未來300年內，我們仍然可以看到氣候變化的影響。”