“Our home planet is dangerously near a tipping point at which human-made greenhouse gases reach a level where major climate changes can proceed mostly under their own momentum.” -James Hansen
As we've seen, the first critical point that everyone needs to understand is the climate has a response lag, which is disguising and delaying most of the effects of the greenhouse gases we've put into the air. By raising the level of CO2 in the air faster than the planet can respond, we've created a package of "on the way" warming headed our way that's three times the actual warming we've experienced so far.
We can still cancel delivery of much of that package of warming, if we quickly bring CO2 in the air back down to a safe level. But since we're still raising the level of CO2 and other greenhouse gases in the air at an accelerating rate, we're letting that opportunity slip away --the package of "future warming" we're sending to our children is getting bigger and bigger every year.