Planetary boundaries has emerged as a widely quoted conceptual framing for potential limits to the carrying capacity of the Earth, especially in policy disciplines. Yet in the original 2009 paper in Nature no planetary boundary for the carbon cycle was suggested. In a 2012 Science paper i suggested global terrestrial net primary production as a carbon cycle boundary. Seven years later, has my idea withstood scrutiny? And more generally, is a planetary boundary for the carbon cycle a useful concept? This seminar will provide all the answers. Steven W. Running has been with the University of Montana, Missoula since 1979, where he is a University Regents Professor Emeritus of Global Ecology. His primary research interest is the development of global and regional ecosystem biogeochemical models integrating remote sensing with bioclimatology and terrestrial ecology. He has worked in the NASA Earth Observing System since 1981, and is responsible for the EOS MODIS global terrestrial net primary production and evapotranspiration datasets. He has published more than 300 scientific articles and two books.. He recently ended Chairing the NASA Earth Science Subcommittee. He now co-chairs the Committee on Earth Science and Applications from Space for the National Academy of Science. Dr. Running was a chapter Lead Author for the Intergovernmental Panel on Climate Change which shared the Nobel Peace Prize in 2007. Dr. Running is an elected Fellow of the American Geophysical Union, and has been designated for many years a Highly Cited Researcher by the Institute for Scientific Information. In the popular press, his essay in 2007, “The 5 Stages of Climate Grief” has been widely quoted. Originally presented February 13, 2019, at NASA's Jet Propulsion Laboratory, Pasadena, California as part of the Center for Climate Sciences Distinguished Climate Lectures series.