How much CO2 emissions would be considered sustainable for humanity?

Question

If climate change is happening because we are producing too much CO2, how much does humanity have to cut back, in order to get to sustainable levels?

Answer 1

I do not know where there would draw the line. I do not think the environment movement has been very clear about it. I just hope the we will still be allowed to exhale.

Answer 2

At this point, that's not certain. Currently, it's obvious that first we have to halt the continuing increase in emissions.

Clearly, some level of emissions is sustainable. But, although exact levelshaven't yet been established, the estimates I've seen say a reduction from current levels of 60-80%.

Which is a lot--but entirely feasible--and the shift to energy efficiency and alternative enrgy will help economic growth rather tan hurt. Bear in mind--that's not something anyone thinks can--or should--be done "overnight." We're talking about policy and infrastructure changes over a period of decades, phasing out older, polluting systems as they wear out with efficient, clean alternative technologies.