Well I suppose these goofy women won't be giving birth until the Earth ends. Actually this is probably a wise decision on their part, but not for the reason they believe.
1. Climate change isn't a "lame career/political cause". It's not like they're putting off children until net neutrality is enshrined in the US constitution. Climate change is an existential threat for large portions of humanity. The scientific consensus on this is virtually unanimous. Until serious, large-scale action against climate change is taken, fearing for the future of any children one may have is perfectly rational, as is opting out of having any.
2. Not having biological children is not the same as skipping parenthood. Adoption exists.
3. Couples that don't have children out of choice are just as happy and fulfilled as those who have them.