They also considered natural ongoing changes in the climate.

他们还考虑到气候不断的自然变化的原因。

The presence of all that water was shaped by natural changes in Earth's climate through time.

所有这些水资源的存在，都是由于地球气候随时间的自然变化而形成的。

It could be a natural change, or a result of rising world temperatures caused by human activity.

可能是自然变化，也可能是人类活动导致全球变暖的结果。

So, like Thales, he thought that there must be an underlying substance that is the source of all natural change.

因此，他和泰利斯一样，认为自然界的一切事物必定是由一种基本物质造成的。

Over the next few years the growing level of human-driven warming will be amplified further by natural but transient changes.

在接下来的几年里，人类驱动的变暖程度不断增加，将因自然但短暂的变化而进一步加剧。

It must have taken quite a bit of courage to come right out and say it, because it meant denying all the natural changes that people could see for themselves.

要坦白说出这个观念一定需要很大的勇气，因为这必定意味着他必须驳斥人们亲眼所见到的种种自然界的变化。