More and more climate science seems to imply we need to eliminate most greenhouse emissions over a time frame closer to 20 years than 50. This has a number of important implications:

It strengthens the case for standard-based regulation and public investment as the main drivers of change, with price as secondary reinforcement. As Tom Laskawy points out, price “will certainly help smooth the bumps in the road to a low-carbon economy. But it will be governments — through mandates, efficiency requirements and infrastructure spending — that will pave the way.”

It implies a strong case for diverting carbon revenue into refunds rather than green investment. If we effectively lower emissions, then emissions will have to begin to drop faster than prices rise about halfway through the process. At that point revenue from auctions or taxes will peak and begin to drop. However, the transition will only be around half-over at that point. We don’t want reductions to depend on a declining revenue source before emission drops are complete. At the point where dedicated revenues drop, the pressure is always to be “responsible” and reduce the program to match the declining funds, rather than finding additional sources.

It implies a strong case for deploying the technology we have rather than waiting for breakthroughs. If we have to massively reduce emissions over the next 20 years, a five-year delay loses a quarter of our transition time.