CO2 capture and planetary albedo management are going to be the only way. For cO2 capture to be meaningful, we need to increase our planetary energy production by 2 or 3x so we can put that energy into sequestration, and obviously those gains cannot be based on fossil fuels. Albedo management is much faster to roll out, but will have a lot of pushback because it will also create locally undesirable outcomes.

The tipping point is one bad summer. Photosynthesis stops at 40-45c (some plants like cactuses can do night processing based on stored energy, but staple crops don’t do that). If we have just one bad summer, billions will die. Civilization is perpetually just a week or two without food for 30 percent of the population away from complete collapse, and it takes thousands of years of stable conditions to recreate.

If we have a bad summer in the northern hemisphere, we could easily lose the capability to sequester carbon or manage planetary albedo in a meaningful way. Stopping emissions is not a solution at this point, we are already way too deep in self reinforcing methane loops for that to even be the primary factor in warming acceleration.

It’s an inconvenient truth, to be sure.