Effect of urban symbiosis development in China on GHG emissions reduction

This paper analyzes current urban symbiosis development and application in China, and then conducts a statistical analysis of the emissions reduction of CO2 and CH4 in relation to recovery of iron and steel scraps, waste paper, and waste plastics from 2011 to 2014 using the greenhouse gas（GHG） emission inventory calculation method provided by the IPCC. Results indicate that the cumulative recovery of renewable resources during China＇s main urban symbiosis development in 2011-2014 was 803.275 Mt, and the amount of iron and steel scraps, waste paper, and waste plastic recovery was the largest, respectively accounting for 62.2%, 18.0%, and 8.2% of total recovery in 2014. In addition, the cumulative emissions reduction of GHGs in relation to recovery of iron and steel scraps, waste paper, and waste plastics in 2011-2014 was27.962 Mt CO2-eq, 954.695 Mt CO2-eq, and 22.502 Mt CO2-eq, respectively, thereby totaling 1005.159 Mt CO2-eq. Results show a remarkable GHG emissions reduction during 2011-2014.

Carbon Capture and Storage:History and the Road Ahead

The large-scale deployment of carbon capture and storage(CCS)is becoming increasingly urgent in the global path toward net zero emissions;however,global CCS deployment is significantly lagging behind its expected contribution to greenhouse gas emission reduction.Reviewing and learning from the examples and history of successful CCS practices in advanced countries will help other countries,including China,to promote and deploy CCS projects using scientific methods.This paper shows that the establishment of major science and technology CCS infrastructures in advanced countries has become the main source of CCS technological innovation,cost reduction,risk reduction,commercial promotion,and talent training in the development and demonstration of key CCS technologies.Sound development of CCS requires a transition from pilot-scale science and technology infrastructures to large-scale commercial infrastructures,in addition to incentive policies;otherwise,it will be difficult to overcome the technical barriers between small-scale demonstrations and the implementation of million-tonne-scale CCS and ten-million-tonne-scale CCS hubs.Geological CO_(2) storage is the ultimate goal of CCS projects and the driving force of CO_(2) capture.Further improving the accuracy of technologies for the measurement,monitoring,and verification(MMV)of CO_(2) storage capacity,emission reduction,and safety remains a problem for geological storage.CO_(2) storage in saline aquifers can better couple multiple carbon emission sources and is currently a priority direction for development.Reducing the energy consumption of lowconcentration CO_(2) capture and the depletion of chemical absorbents and improving the operational efficiency and stability of post-combustion CO_(2) capture systems have become the key constraints to largescale CCS deployment.Enhanced oil recovery(EOR)is also important in order for countries to maximize fossil fuel extraction instead of importing oil from less environmentally friendly oil-producing countries.