<p>Dans le sillage des Objectifs de D&eacute;veloppement Durable (ODD) de l&#39;ONU, et des rapports du Groupe d&#39;experts Intergouvernemental sur l&#39;Evolution du Climat (GIEC), les incitations &agrave; r&eacute;pondre &agrave; l&#39;urgence de la lutte contre le r&eacute;chauffement climatique et &agrave; la pr&eacute;servation de la biodiversit&eacute;, se font de plus en plus pressantes. A partir de la pens&eacute;e complexe (Morin, 1977-2004) mais aussi d&#39;un traitement se voulant interdisciplinaire (&eacute;pist&eacute;mologie, philosophie, sociologie, psychologie, math&eacute;matiques ...), cette revue de question tentera d&#39;appr&eacute;hender ce qu&#39;est l&#39;&eacute;cologie de l&#39;action (Morin, 1980) dans toute sa complexit&eacute; et abordera les conditions, les obstacles et les changements d&#39;ordre &eacute;pist&eacute;mologique, ontologique et &eacute;ducationnel que n&eacute;cessite cette action. Il ne sera pas tant question de proposer des actions concr&egrave;tes que de r&eacute;fl&eacute;chir aux transformations de la pens&eacute;e que n&eacute;cessitent ces actions. Ainsi les concepts de complexit&eacute;, d&#39;&eacute;cologie de l&#39;action, d&#39;&eacute;co-ontologie, de r&eacute;sonance et de capabilit&eacute;, tous concourant &agrave; appr&eacute;hender le monde dans toute sa complexit&eacute;, nous guiderons pour esquisser ce que pourrait &ecirc;tre un &eacute;cologue de l&#39;action.</p> <p>In the wake of the United Nations&#39; Sustainable Development Goals (SDG) and the reports of the Intergovernmental Panel on Climate Change (IPCC), the pressure is increasing to respond to the urgent need to combat global warming and preserve biodiversity. Drawing on complex thinking (Morin, 1977-2004) and an interdisciplinary approach (epistemology, philosophy, sociology, psychology, mathematical, etc.), this review will attempt to understand what is the ecological of action (Morin, 1980) in all its complexity, and will address the conditions, obstacles and changes of an epistemological, ontological and educational nature that this action requires. It will not to deal with the question of proposing concrete actions as of reflecting on the transformations in thinking that these actions require. The concepts of complexity, ecology of action, eco-ontology, resonance and capability, all of which contribute to understanding the world in all its complexity, will guide us as we sketch out what an ecologist of action might be.</p> <p><strong>Remerciements:</strong></p> <p>Remerciements &agrave; Gabriel Cohen-Aknine, doctorant EuroMov Digital Health in Motion, Univ Montpellier, IMT Mines Al&egrave;s, CHU de N&icirc;mes et toute l&#39;&eacute;quipe d&#39;organisation de la Journ&eacute;e de l&#39;Ecole doctorale SHM (Sciences du Mouvement Humain ED 463) qui par leur proposition de participation &agrave; une table ronde ont &eacute;t&eacute; les inspirateurs de cet article. Merci &agrave; Fr&eacute;d&eacute;ric Wurtz et Freddy Bouchet, directeurs de recherche au CNRS pour leurs encouragements. Des remerciements vont &eacute;galement &agrave; cette jeunesse qui invite &agrave; consid&eacute;rer la question &eacute;cologique en complexit&eacute;, avec gravit&eacute; et sans verser dans le d&eacute;sespoir; &agrave; Julian, Clothilde et Marid&eacute;lys.</p> <p><meta charset="UTF-8" />Thanks to Gabriel Cohen-Aknine, doctoral student at EuroMov Digital Health in Motion, Univ Montpellier, IMT Mines Al&egrave;s, CHU de N&icirc;mes and the whole organising team of the SHM (Sciences du Mouvement Humain ED 463) doctoral school day who, through their proposal to participate in a round table, were the inspiration for this article. Thanks to Fr&eacute;d&eacute;ric Wurtz and Freddy Bouchet, CNRS research directors, for their encouragements. I would also like to thank the young people who invited us to consider the ecological issue in all its complexity, with seriousness and without despair: Julian, Clothilde and Marid&eacute;lys.</p>