Why we called earth in danger? Why we not called mankind in danger?its mine opinion

It would help if you could tell us what you are thinking
about here -- what is it that is making the Earth (or the people) be in
danger?

In general, I think we would say this sort of thing
because from our point of view, the Earth is only important because we humans are on
it.

When we say global warming, for example, puts the Earth
in danger, of course you are right to say this is wrong.  In fact, only people (and some
animals and plants) are in danger.

But because we seem like
the most important things on Earth, we say that the Earth is in danger whenever we
people are in danger.