Atmospheric evidence for a global secular increase in isotopic discrimination of land photosynthesis
Ralph F Keeling, University of California San Diego, Scripps Institution of Oceanography, La Jolla, CA, United States, Heather D Graven, Imperial College London, London, SW7, United Kingdom, Lisa R Welp, Purdue University, Department of Earth, Atmospheric, and Planetary Sciences, West Lafayette, IN, United States, Stephen C Piper, University of Calif, San Diego, La Jolla, CA, United States, Alane Bollenbacher, University of California San Diego, La Jolla, CA, United States, Laure Resplandy, Scripps Institution of Oceanography, La Jolla, CA, United States and Harro A J Meijer, University of Groningen, Groningen, 9727, Netherlands
