The World s Population； World Population； WorldPopulation； in world population 这些都可以!
例句：
我刚才是表示这样的看法：我们正在失去对世界人口的控制.
I was just expressing the view(that) we are losing control of the world population.
世界人口中约三分之一生活在被视为不自由的国家,而这部分人口超过半数生活在中国.
Around a third of the world's population live in countries deemed not free,although over half of these live in China.
今天值此纪念世界人口日之际,让我们重申对于保证人类尊严、自由生活不受恐惧及物资匮乏困扰权利的承诺.
Today as we commemorate World Population Day,let us renew our commitment to human dignity and the right to live in freedom from fear and want.
