| Summary: | One of the most important natural causes of climate change are large volcanic eruptions as they have a significant impact on Earth's global climate system, especially on the tropospheric and stratospheric circulation. The direct injection of gases, aerosols and volcanic ash into the stratosphere has a strong and long lasting radiative influence, which leads to a global reduction in surface temperatures, and a pronounced warming of the stratosphere, for several years or even decades. To evaluate the climate response and feedback to an extremely large volcanic eruption we use the complex MPI-Earth System Model (ESM) by forcing it with a simulated Aerosol Optical Depth (AOD) distribution resulting from a stratospheric injection of 700 Mt SO2, corresponding to the Los Chocoyos eruption (VEI>7) in Guatemala (84 ka BP). To take into account the unknown season of the eruption, we perform experiments for January and July eruptions, including five ensemble simulations for each. We consider global atmospheric effects as well as changes in the ocean circulation, sea ice and the carbon cycle, which are generated by complex relationships between the radiative forcing and the earth climate system on different time scales. In this study we show that the global surface temperature and especially the tropical precipitation drop rapidly before they recover within 8 years. The ocean response indicates a reduction in ocean heat content, a strengthening of the Meridional Overturning Circulation (MOC) and a sensitivity of the sea ice content on longer time scales. Finally modifications in the CO2 storage of the earth climate system comprising the ocean, land and atmospheric CO2 concentrations are investigated
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