By the end of this century, almost every country in the world could have a shrinking population. Although people are living longer due to advances in healthcare and a decline in poverty, they are also having fewer babies. Over the past 50 years, the global fertility rate — the total number of births per woman — has roughly halved to 2.3. In most advanced economies it is already well below the replacement rate of 2.1, where the population replaces itself from one generation to the next, taking into account mortality. Developing nations are on a similar downward trajectory. The upshot is a decline in the working-age population across the developed world, which will bring significant social, economic and political costs if left unaddressed. Some blame a dystopian outlook among millennials and Gen Z — from the harms their children may cause to the climate, to the harms the climate may also do to them. But while a child-free life has gained appeal among some youngsters, for multiple reasons, the vast majority of under-30s in America who do not have kids still want them.
到本世纪末，manbetx app苹果 几乎所有国家的人口都将减少。尽管医疗保健的进步和贫困人口的减少使人们延长了寿命，但婴儿数量也在减少。过去50年里，manbetx app苹果 生育率——每名妇女生育的总人数——大约减半到2.3。在大多数发达manbetx20客户端下载 体，该数字已远远低于2.1的人口更替率，即考虑到死亡率，人口实现代际更替的生育率。发展manbetx3.0 家也处于类似的下行轨道上。