I just dispute the conclusion it suddenly jumps to without presenting any evidence:
"...the Earth systems can't cope with it"
and
"On such a crowded planet, we have little capacity to adapt to changes..."
Eh, I agree that's just alarmist pap.
On the other hand, the actual measurements and rates of change of CO2 and Methane and other gasses do concern me, and are undisputed by any mainstream scientists I'm aware of.
The majority agree something major is going on, regardless of whether we understand the source. We should pay attention.
As others have noted, no matter what, we need to be looking at alternative energy sources and treating the environment better - if nothing else, it's in our own self-interest for medium- and long-term survival.