I've long been worried about
the arguments of Ray Pierrehumbert and Myles Allen about short lived climate pollutants[SLCPs]. These seem to imply that SLCPs, such as methane and black carbon, are only important when global temperature is near its peak.
One worry is that the short term rise in global temperatures induces feedbacks - e.g. increased CO2 emissions from stored soil carbon. Another is that since the time of "the peak" is not known with certainty, we won't know when to start cutting back on SLCPs.
However, I have recently become aware that the short term warming can increase the heat stored in the Earth, e.g. heat in the oceans and in the latent heat of melted ice. (I vaguely remember a comment here some time ago about latent heat and what might happen when the ice is melted from various regions.) I have come across
Centuries of thermal sea-level rise due to anthropogenic emissions of short-lived greenhouse gases by Ramanathan et. al.The “significance” includes:
Our study shows that short-lived GHGs contribute to thermal expansion of the ocean over much longer time scales than their atmospheric lifetimes. Actions taken to reduce emissions of short-lived gases could mitigate centuries of additional future sea-level rise.
Peak temperature arguments appear to say that bad things happen when global temperatures reach a certain threshold but their severity is independent of the path taken too reach that threshold.
This implies that a 2°C increase in global temperatures brings the same problems independent of the heat stored lower in the oceans or how much of the ice caps have melted.
How big is the stored heat and are there consequences other than sea level rise?
Does the emphasis on peak temperature sideline other important measurements?
Should we look for other measurements to supplement global temperature targets?
