If Some Critical Regions Achieve Carbon Neutrality, How Will the Global Atmospheric CO2 Concentration Change?

Abstract

Due to anthropogenic emissions, the global CO2 concentration increases at a rate of approximately 2 ppm per year. With over 130 countries and regions committing to carbon neutrality goals and continuously reducing anthropogenic CO2 emissions, understanding how atmospheric CO2 concentrations will change globally and in other regions has become an intriguing question. Examining different regions’ efforts to reduce anthropogenic CO2 emissions through atmospheric CO2 observations is also meaningful. We used prior and posterior fluxes to drive the TM5 model. The posterior fluxes were based on the China Carbon Monitoring, Verification and Support System for Global (CCMVS-G), which assimilated the atmospheric CO2 concentration data from ground-based observation and satellite observation. We found that the CO2 concentration obtained using the posterior fluxes was more in line with the actual situation. Then, we presented some experiments to estimate how global and regional CO2 concentrations would change if certain key regions and the whole world achieved net zero emissions of anthropogenic CO2. After removing carbon fluxes from China, North America, and Europe, global CO2 concentrations decreased by around 0.58 ppm, 0.22 ppm, and 0.10 ppm, respectively. The most significant decrease occurred in the regions where fluxes were removed, followed by other areas at the same latitude affected by westerly winds. This indicates that fossil fuel flux is the main factor affecting CO2 concentrations, and that meteorological-driven transportation also significantly impacts CO2 concentrations. Most importantly, using this method, it is possible to quantitatively estimate the impact of achieving carbon neutrality in one region on CO2 concentrations in local regions as well as globally.