Feedback emissions add 0.2-0.4°C and shorten 1.5°C timeline by up to 25%

The Technology Review article reports that major CMIP models feeding UN assessments omit most warming-induced greenhouse gas releases. A March One Earth analysis isolated three regional sources and calculated they compress the remaining time to consistent 1.5°C and 2°C exceedance by as much as 25 percent. Both studies rely on aggregated observational and modeling papers rather than new primary runs.

IPCC AR6 carbon budgets rest on equilibrium climate sensitivity estimates that exclude these loops. The resulting underestimation means official remaining-emissions allowances are larger than the physical system supports once permafrost carbon, wetland CH4, and fire-driven CO2 are included. This discrepancy scales directly with the rate of initial warming, amplifying policy error margins.

The Warming-Induced Greenhouse Gas Emissions Model Intercomparison Project now coordinates 20-plus teams on standardized experiments. Results are scheduled for input into the 2029 AR7 report. Parallel field trials at Woodwell target fire suppression and wetland chemistry modification to test whether feedback fluxes can be reduced at scale before AR7 finalizes revised budgets.

Operational consequence is immediate: national net-zero pathways calibrated to current IPCC ranges require downward revision of allowable cumulative emissions once the intercomparison outputs are adopted.