wildlife populations have fallen by an average of almost 70%, 野生动物种群就已平均下降将近70%

315. has not been felt for 66 million years.
     已经是6600万年前的事了
316. Now we're on track for the sixth.
     如今我们正在走向第六次
317. In the last 50 years alone,
     光是在过去的50年中
318. wildlife populations have fallen by an average of almost 70%,
     野生动物种群就已平均下降将近70%
319. and this time, we are the ones responsible.
     这一次 我们是罪魁祸首
320. And yet despite this grim forecast,
     虽然前景黯淡
321. there remains a glimmer of hope.
     但仍有一线希望

来自《我们星球上的生命 第一季 第八集 Life on Our Planet S01E08 冰与火的世纪》第 318 行