global warming will be harder to fight than scientists thoughtDuring documented episodes of global warmth, he says, the method reveals relatively low CO2 values, nothing like the levels of 2000 ppm or more suggested by other proxies. If these downward revisions hold, Earth may be even more sensitive to injections of CO2 than current models predict. “Temperatures are going to climb further for less carbon and we better be mindful of that,” Franks says.
Once again, the conservative initial estimates are shown to be wrong upon refinement.
To me it looks like one of the knowledge gaps is CO2 recycling in the oceans. Even the studies by Archer probably overestimate the CO2 burial flux. Warming surface oceans likely transition to a net re-emission mode from a net sequestration mode. So atmospheric CO2 levels persist for millions of years and not a few thousand. Yes, even chemical weathering is not fast enough. The notion of some giant garbage can that will take our trash to any level we want is a persistent one. And dead wrong.