People didn’t come to realize the importance of planting trees until they (had) experienced a number of serious natural disasters.

经历了多次严重自然灾害后，人们才逐渐意识到植树造林的重要性。

youdao

Pakistan has been hit by a number of recent natural disasters and Zardari believes that they are at least somewhat connected to global warming caused by the burning of fossil fuels.

巴基斯坦最近遭遇了一系列自然灾害的袭击。扎尔·达里相信，这些灾难至少与燃烧石化燃料引发的全球变暖存在一定的关系。

youdao

We've seen, in this region, a number of devastating natural disasters, and when we have strong cooperation and training between our countries then we're in a stronger position to respond quickly.

WHITEHOUSE: The White House