The carbon footprint response to projected base stations of China's 5G mobile network.

While the rapid expansion of China's 5G mobile network helps to speed up the nation's economic and social development, it tends to release more CO due to the 5G's significant energy demand, hampering sustainable development of the 5G network. Previous assessments of CO emissions from China's 5G development were based on a projected 5G network ranging from six to fifteen million base stations with the absent of a convincing business model in 5G's application. Under the scenario of business-estimated six million base stations in 2030, the share of electricity consumed by China's 5G networks in 2030 could reach 8.4 % of the national total power generation, causing 0.44 GtCO/yr CO emissions. We collected 5G base station numbers in 2020 and 2021 in 31 provinces and province-level municipalities (PLM), the period with the rapid growth of the 5G base stations in China. We linked these provincial base stations with provincial Gross Domestic Product (GDP), population (POP), and big data development level (BDDL) and established a statistical model to predict 5G base stations by 2030. The model predicted 2-5 million 5G base stations by 2030, considerably lower than the business-projected base station number. Under the model predicted 5G base stations, China's 5G network could yield 0.15-0.29 GtCO/yr emissions subject to the nation's BDDL from 40 to 80 % by 2030. Both 5G base stations and CO emissions are significantly lower than the previous estimates. We decomposed the CO footprint of China's 5G networks and assessed the contribution of the number of 5G base stations and mobile data traffic to 5G-induced CO emissions. We find that increasing the application of clean energy and promoting energy efficiency can reduce CO emissions in the 5G network. To more accurately estimate 5G's climate effect, we propose that it urgently needs to improve vivid 5G business models.