Recently, the team led by Academician Wu Lixin from Frontier Science Center for Deep Ocean Multispheres and Earth System and Physical Oceanography Laboratory (MOE) has made significant progress in studying the historical and future changes in downward solar radiation at the Earth's surface. Their findings, titled A Long-term Decline in Downward Surface Solar Radiation, were published in National Science Review.

Downward surface solar radiation (DSSR) is essential for the energy balance of the atmosphere at the surface and is a key factor influencing the output of green energy—specifically solar energy. The research team utilized the latest generation of CMIP6 climate models, and found that all CMIP6 models consistently demonstrate a notable decline in DSSR from 1959 to 2014, predominantly driven by human-induced forcing. Following the 1980s, global aerosol emissions decreased significantly; however, the reduction in global DSSR showed no signs of slowing down (Figure 1), suggesting that other critical factors may also influence the changes in DSSR. Additionally, through single forcing experiments (examining the effects of greenhouse gas forcing and anthropogenic aerosol forcing separately), the team confirmed that both water vapor (which is primarily regulated by greenhouse gases) and anthropogenic aerosols contribute equally to the decline in global DSSR, with the role of greenhouse gases more significant after 1979.

The study presents a comprehensive analysis of the historical changes in downward surface solar radiation (DSSR) from a global perspective (including both land and ocean). It stands as the first case to quantify the relative contributions of greenhouse gases and anthropogenic aerosols, highlighting the significant role of water vapor in the historical decline of DSSR. Furthermore, the study indicates that the future trajectory of DSSR is heavily dependent on emission scenarios. Therefore, the adoption of clean and low-carbon emission policies will be instrumental in mitigating further reductions in DSSR, thereby providing essential support for a smooth transition from conventional fossil fuels to renewable energy sources. This research not only enhances our understanding of atmospheric energy changes in the context of global warming, but also establishes a theoretical foundation for addressing global concerns and national demands related to variations in solar energy availability.