Patent publications only account for ~10% in this document pool, whereas on average, patents account for a third of the total documents in CAS Content Collection within similar time frame, suggesting a relatively small commercial interest on this research topic. However, the distinct count of concepts being introduced to this field showed a steep increase in the last 10 years, especially in journal publications (Figure ), suggesting new ideas or methods being tested. To reveal how this research effort has been distributed among countries/regions around the globe, we grouped the publications according to the country/region of the first author affiliated organization (journal publications) or the country/region of the patent assignee (patent publications). Figure shows the same ten countries/regions are responsible for the largest numbers of both journal and patent publications in our data set. Publication trends over the past 20 years show that China has steady growth both in journal and patent publications, while India shows similar growth in journal publications; these increases may be driven by the increasing CO2 emissions in both China and India. (Figure ). In CCS literature, the United States shows a small