Spatial–Temporal Characteristics of the Emission Intensities of Several Major Greenhouse Gases and Aerosols under CMIP6 Scenarios

Eight latest scenarios (SSPx-y scenarios), which are based on different shared socioeconomic paths (SSPs) are adopted in the Coupled Model Intercomparison Project Phase 6 (CMIP6) to project the probable magnitude and trend of future climate changes. In this article, the emission datasets of various major greenhouse gases and aerosols under the eight SSPx-y scenarios are analyzed, including emission intensities in the reference year (i.e., 2015), spatial and temporal variations of future emission intensities, and yearly change in emission intensities for the six typical selected sub-regions. Results show that the strongest emission intensities of carbon dioxide (CO₂), methane (CH₄), black carbon (BC), and sulfur dioxide (SO₂) are distributed mainly in East and South Asia in 2015. In comparison with the reference year, variations in the intensities of CO₂ and CH₄ emissions in 2100 show significant differences between the high and low radiative forcing scenarios. In addition, the average global emission intensities of BC and SO₂ in 2100 are weaker than those in the reference year under all scenarios. In terms of temporal variation, such as the development of bioenergy with carbon capture and storage (BECCS), the values of CO₂ emission intensities in all sub-regions become negative in 2100 for four low radiative forcing scenarios (i.e., radiative forcing values≤3.4 W/m²). On the other hand, the net intensity of negative emissions in South America is －0.3 kg m^－2 a^－1 under the SSP5-3.4 scenario in 2100, which is lower than that in all other sub-regions. Finally, a comparison of the variations in emission intensities in East and South Asia reveals that emission reduction actions in East Asia play a more effective role than those in South Asia in the future development described in all scenarios.