It's not necessarily an exageration. I'm a firm believer that there is a point where the momentum of a situation is irreversible. Climate change will occur anyway but we are certainly not helping it. Normally it would be like a car running at 30 mph on gasoline. Humans have come in and strapped a nitro booster on the situation and it's accelerating to a point of being out of our control.
Then again "control" is a stupid word to use. We can't control nature. Earthquakes, tsunamis, tidal changes, volcanic activity, asteroids. Can't do **** about any of them despite what the nerds say.
The more species we kill off the more the balance swings artificially.
What we can do is minimise our effect on these elements. Nobody in power will do anything, especially in the USA, until enough scientists tell them it is either borderline or too late. George W Bush probably thinks global warming is something invented to keep your testicles hot in winter.