“Net Negative 110 by 2068”

Here’s a note from Mark McElroy:

For all of the talk of Net Zero GHG emissions, even the most aggressive IPCC-sanctioned 1.5 degree pathways, like SSP1-1.9, do not result in temperatures at or below 1.5 degrees (over preindustrial levels) when Net Zero is reached. Net Zero is just a milestone along the way to what really needs to happen, or what I call “Net Negative 110” (i.e., -110% in CO2 emissions over 2015 levels by 2068).

Indeed, under the SSP1-1.9 pathway, Net Zero is called for by 2058, not 2050. From that point forward, emissions must go negative. And if all goes according to plan, temperatures will still not have settled down to 1.5 degrees above preindustrial levels. That won’t happen until 2068, ten years later. Think of Zero as -100%. Then subtract another 10 percent off 2015 levels by 2068, and you’ll have what you need to cap things off at 1.5 degrees — assuming, of course, we’ve met every other interim annual target between 2015 and 2068.

So the real mantra we should all be chanting is “Net Negative 110 by 2068”, not “Net Zero by 2050”. Net Zero by 2050 is so yesterday …