Effects of multi-observations uncertainty and models similarity on climate change projections

Abstract Climate change projections (CCPs) are based on the multimodel means of individual climate model simulations that assumed to be independent. However, similarity leads biased toward largest set similar models and intermodel uncertainty underestimation. We assessed influences similarities in CMIP6 through CMIP3 CCPs. ascertained from shared physics/dynamics initial conditions by comparing simulated spatial temperature precipitation with corresponding observed patterns accounting for spread relative observational uncertainty, which is also critical. After similarity, information 57 CMIP6, 47 CMIP5, 24 can explained just 11 independent without significant differences globally averaged statistics. On average, indicate a lower global-mean rise 0.25 °C (~0.5 °C–1 some regions) all end 21st century under CMIP6’s highest emission scenario.