Sitting at home waiting for a delivery, so just a quick post. There’s been a new narrative, on social media at least, that we may be heading for a plateau in global emissions. The suggestion, then, is that we are on track to follow one of the lower representative concentration pathways (RCP4.5, for example). This would be a good step, if true, but it seems to be based on a single assessment that suggests that emissions in 2040 will be similar to those today. Not only do there appear to be other assessments that disagree, what some seem to be concluding from this appears to confuse stocks and flows.
What will ultimately determine how much we warm will be how much we emit in total. Emissions in a single year might give a clue as to what this would be, but it’s really going to depend on emissions across the whole time period. In particular, for the mid-range RCPs (RCP4.5 and RCP6) most of the emission reductions happen after 2040. So, emissions in 2040 may be a poor guide to how much we are likely to emit in total.
It would, of course, be great if we are starting to see emissions plateauing and, eventually, starting to drop. One concern I have with the current narrative is the suggestion that somehow it is happening without us really having done very much. It’s possible, I guess, but it would seem rather unfortunate if we start to think that we’ve almost solved this problem and then discover that emissions have continued rising. Maybe a better narrative would be one where we highlight how we might be heading for a plateau in emissions and then suggest that we aim for a fall, rather than simply a plateau.