CO2 reached 1980s (352 ppm, average) to 2000s (380 ppm, max) levels 2500-5500 years ago in Japan per stomata records. Scientists (Wang et al., 2020) have determined stomatal evidence can uncover large short-term CO2 fluxes of 50-100 ppm within a century or less. Measurements from a forest near Mt. Kurikoma, Japan, reveal minimum to maximum … Continue reading New Study Finds CO2 Reached 1980s-2000s Levels About 4,000 Years Ago In Japan