Exposing the Forcing of the Global and Nino 3.4 Temperatures to Higher Levels by the South East Asian Aerosol Plume Using CMIP6, MERRA‐2, MODIS on TERRA, Last Millennium Ensemble, and Volcanic Eruption Data

Abstract The Historical Experiment (HE) assesses CMIP6 climate models against the known climate (1850–2014) where carbon dioxide (CO 2 ), the global temperature and aerosols have followed similar, low frequency, rising trajectories and models are required to use “forcings based as far as possible on observations.” To assess the effect of three equatorial, continental scale aerosol plumes over South East Asia (SEAP), Amazonia and West Africa on global and Nino 3.4 temperatures I filtered 23 CMIP6 data sets with a High‐Pass Filter (HPF) and find that the SEAP causes: reduced surface radiation (4.3 W/m 2 ) and increased OMEGA (0.005 Pa/s) in the SEAP Area; the global and Nino 3.4 temperatures to rise by 0.16 and 1.65 K as the SEAP Aerosol Optical Depth (AOD) rises; with CO 2 having a slightly negative effect. I also show that the HPF AOD of the three plumes is too low in 22 models at 42% (SEAP) 49% (Amazonia) and 69% (West Africa) of the measured data and too high in one and therefore no model meets the HE requirement to use observation based forcings. I also show the SEAP Area volcanoes have a direct influence on the global and Nino 3.4 temperatures and the modeled global and Nino 3.4 temperatures increases are far too high at 9 and 73 K if the CMIP6 SEAP AOD range is adjusted to actual historical levels. I conclude CMIP7 climate models should be tuned using measured aerosol levels from recent decades to correctly allocate the causes of increasing global temperatures.