The contributions of individual countries and regions to the global radiative forcing

Abstract

Knowing the historical relative contribution of greenhouse gases (GHGs) and short-lived climate forcers (SLCFs) to global radiative forcing (RF) at the regional level can help understand how future GHGs emission reductions and associated or independent reductions in SLCFs will affect the ultimate purpose of the Paris Agreement. In this study, we use a compact Earth system model to quantify the global RF and attribute global RF to individual countries and regions. As our evaluation, the United States, the first 15 European Union members, and China are the top three contributors, accounting for 21.9 ± 3.1%, 13.7 ± 1.6%, and 8.6 ± 7.0% of global RF in 2014, respectively. We also find a contrast between developed countries where GHGs dominate the RF and developing countries where SLCFs including aerosols and ozone are more dominant. In developing countries, negative RF caused by aerosols largely masks the positive RF from GHGs. As developing countries take measures to improve the air quality, their negative contributions from aerosols will likely be reduced in the future, which will in turn enhance global warming. This underlines the importance of reducing GHG emissions in parallel to avoid any detrimental consequences from air quality policies.

Divergent Energy-Climate Nexus in the Global Fuel Combustion Processes

“…Since OSCAR is a simplified climate model and needs calibration to enhance the accuracy of its outputs, the R b was rescaled to calculate the AC as done in previous studies. , The rescale factor of RF of each climate forcer and GMST was confirmed by IPCC report value in a certain year t x by the equation: f x = IPCC ( x , t x ) R normalb ( x , t x ) where the x represents the RF of each forcer or GMST, and the t x and IPCC( x , t x ) are shown in Table S2. The AC to the x of combustion source i could be calculated from: normalA normalC i , x = R normalb , x × f x × normalR normalC i , x …”

“…Combustion processes have significant contributions to many short-lived climate forcers (SLCFs), including black carbon and sulfate aerosols, and consequently induce temporary but strong climate impacts compared to CO 2 . It was previously reported that developed regions, including North America and Western Europe, consumed large amounts of fossil fuels and contributed significantly to the global radiative forcing (RF), while in China and India, though there were also high energy consumptions, the cooling SLCFs such as sulfate and organic aerosols partly offset the warming effects of greenhouse gases (GHGs) . There are substantial differences in climate impacts between biomass and fossil fuel combustions when not only CO 2 but also many nonCO 2 climate forcers were taken into consideration …”

Climate Warming Mitigation from Nationally Determined Contributions

“…The normalized marginal attribution method evaluates the contributions of individual regions proportional to their marginal effects and constrains the total of individual contributions equal to the global effect. In many early studies, this method attributed climate changes to processes or specific regions (Ciais et al, 2013;Li et al, 2016;Fu et al, 2020;Fu et al, 2021).…”

“…The model is driven by emission datasets of greenhouse gases and aerosol precursors, which calculate the corresponding changes in atmospheric concentrations before predicting radiation forcing and climate change. OSCAR has widely been used in projections and attributions in climate change communities (Ciais et al, 2013;Gasser et al, 2018), especially for regional climate contributions (Li et al, 2016;Fu et al, 2021). In this study, we use OSCAR v3.1 to simulate future GMST and atmospheric CO2 changes in different scenarios and to attribute the contributions of climate mitigation to different regions.…”

Cultivation and Biorefinery of Microalgae (Chlorella sp.) for Producing Biofuels and Other Byproducts: A Review

“…The United States (U.S.) National Oceanic and Atmospheric Administration (NOAA) reported that global average CO 2 concentrations increased to approximately 417 ppm in 2020 and that the global CO 2 rate is increasing annually. Rising GHG concentrations lead to global warming and climate change, which are believed to aggravate regional and global water scarcity [5,6]. Advanced strategies of CO 2 mitigation have received increasing attention in the last decade [7][8][9], and many countries are actively immersed in processing/developing technologies to reduce GHGs [10,11].…”