Model estimates for climatic effects of anthropogenic GHG emission scenarios in the 21st century

Abstract

To estimate the climatic effects of anthropogenic CO2 and CH4 emission scenarios we performed numerical experiments using IAP RAS CM global climate model. Emissions pathways of 5 RCP (Representative Concentration Pathways) regions were used as evaluated scenarios. It is shown that the anthropogenic contribution of CO2 to global surface temperature change starts to decrease in the second half of the century only for RCP 2.6 and only for ASIA, OECD and REF emission scenarios. The rest of the CO2 emission scenarios contribute to an increase in the global surface temperature of the atmosphere throughout the 21st century. The growth of the compensatory effect of natural CO2 fluxes generally slows down by the end of the 21st century. Impact of anthropogenic methane emissions on climate stabilizes in the 21st century for all scenarios under RCP 2.6, 4.5 and 6.0. The estimates of GHG climatic cost equal up to 24 mK per PgC for CO2 and up to 0.9 mK per Tg for CH4. Methane is shown to have at least 40 times stronger impact on global surface temperature per molecule than CO2.