Prof Philippe Ciais: The world’s most highly cited climate scientist

Phillipe Ciais has spent almost four decades researching the planet’s carbon cycle – and the ways in which humans have been impacting its balance. Based at the Laboratoire des Sciences du Climat et de l’Environnement (LSCE) on the outskirts of Paris, Ciais (pronounced “see-es”) has been listed as an author on more than 1,300 peer-reviewed studies. In fact, analysis of Carbon Brief’s Cosmos database reveals that – by some distance – he is the most highly cited climate scientist in the world. This interview was conducted by Leo Hickman at Laboratoire des Sciences du Climat et de l’Environnement (LSCE) on 28 May 2026. Filming by Joe Goodman. Our Creative Commons license: you are welcome to reproduce original material unadapted in full for non-commercial use, credited ‘Carbon Brief’ with a link to the original article. Please contact us for commercial use. https://www.carbonbrief.org Music credit: Into Infinity artists Unrecognisable Now, Naohito Uchiyama, Languis (CC BY-NC 3.0 US). 00:00 Intro 01:17 'Atmospheric inversion' and 'flux' 04:12 Human impacts on 'fluxes' 06:00 Natural solutions 07:10 Carbon budget imbalance 12:05 CDR 16:35 Methane 18:31 Proxy data 20:03 Climate sensitivity 21:15 Trump administration 23:20 Working in China 28:42 What would you do with €100 33:22 IPCC 36:55 Paris Agreement 41:04 Self-reporting emissions 43:22 AI 50:45 Authoring 1,000 studies 53:30 Most memorable study 55:30 What keeps you up at night 57:39 First memory of climate change