I know these two sentences are correct:
Europeans consider climate change to be the most serious problem facing the world.
Perhaps the most serious problem facing the environment is global warming.
But I really do not understand the grammar. I think the first sentence should be...
Europeans consider climate change to be the most serious problem the world is facing.
And the second one should be...
Perhaps the most serious problem the environment is facing is global warming.
This is extremely confusing for Chinese native speakers, as in Chinese it does not make sense to say "A problem is facing the world" or "A problem is facing the environment".
Can anyone explain the reason?