Marta Moreno-Ibáñez ^1,2* Mathieu Casado ³ Gwenaëlle Gremion ⁴ Valentina Rabanal ^5,6 Onema Adojoh ^7,8 Chukwuma Anoruo ⁹ Adnan Arshad ^10,11 Attig Bahar Faten ^12,13 Cinthya Bello ¹⁴ Helena Bergstedt ¹⁵ Jilda A. Caccavo ^16,3 Nicolas Champollion ¹⁷ Emily S. Choy ¹⁸ María Fernanda De Los Ríos ¹⁹ Henrieka Detlef ²⁰ Rahul Dey ²¹ Gamil Gamal ²² Hugo Guímaro ^23,24 Susana Hancock ^25,26 Christel Hansen ²⁷ Vincent Hare ^28,29 Juan Höfer ³⁰ Thajudeen Jabir ³¹ Shipra Jain ³² Shridhar Jawak ^33,34,35 Mikhail Latonin ^36,37 Joseph Martin ^38,39 Jhon Mojica- Moncada ^40,41 Ryan O'hara ⁴² Olumide Onafeso ⁴³ R. Arun Prasath ^44,45 Eduardo Queiroz Alves ⁴⁶ Sergio Raez-Villanueva ⁴⁷ Paul Rosenbaum ^48,49 Sebastián Ruiz Pereira ^50,51 Valentina Savaglia ^52,53,54 Maud van Soest ⁵⁵ Deniz Vural ^56,57

• ¹ Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, United States
• ² National Snow and Ice Data Center, University of Colorado Boulder, Boulder, Colorado, United States
• ³ UMR8212 Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Gif-sur-Yvette, France
• ⁴ Institut des sciences de la mer de Rimouski, Université du Québec à Rimouski, Rimouski, Quebec, Canada
• ⁵ Servicio Meteorológico Nacional (SMN Argentina), Buenos Aires City, Argentina
• ⁶ Young Earth System Scientists (YESS), Buenos Aires City, Argentina
• ⁷ Natural Sciences - Geology, Northwest Missouri State University, Maryville, United States
• ⁸ Department of Earth, Environmental and Planetary Sciences, College of Arts and Sciences, Case Western Reserve University, Cleveland, Ohio, United States
• ⁹ Department of Physics and Astronomy, University of Nigeria, Nsukka, Enugu, Nigeria
• ¹⁰ State Key Laboratory of Grasslands & Agroecosystem, Lanzhou University, Lanzhou, China
• ¹¹ PODA-Pakistan, Islamabad, Pakistan
• ¹² Tunisia Polytechnic School, University of Carthage, La Marsa, Tunisia
• ¹³ Institute of Social and Economic Research, Rhodes University, Grahamstown, South Africa
• ¹⁴ Carrera de Biología Marina, Universidad Científica del Sur, Lima, Peru
• ¹⁵ B.Geos, Korneuburg, Austria
• ¹⁶ UMR7159 Laboratoire d'Océanographie et du Climat Expérimentations et Approches Numériques (LOCEAN), Paris, France
• ¹⁷ Institut des Géosciences de l'Environnement, CNRS / UGA / Grenoble-INP / IRD / INRAE, Saint-Martin d'Hères, France
• ¹⁸ Department of Biology, Faculty of Science, McMaster University, Hamilton, Ontario, Canada
• ¹⁹ Universidad Nacional Agraria La Molina, Lima, Peru
• ²⁰ Department of Geoscience, Aarhus University, Aarhus, Denmark
• ²¹ National Centre for Polar and Ocean Research (NCPOR), Vasco da Gama, India
• ²² Department of Natural Resources, Faculty of African Postgraduate Studies, Cairo University, Giza, Beni Suef, Egypt
• ²³ Marine and Environmental Sciences Centre, Department of Life Sciences, University of Coimbra, Portugal
• ²⁴ British Antarctic Survey, Natural Environment Research Council, Cambridge, United Kingdom
• ²⁵ Arctic Basecamp, Rotterdam, Netherlands
• ²⁶ The Greenland Project, Copenhagen, Denmark
• ²⁷ Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria, South Africa
• ²⁸ Stable Light Isotope Laboratory, Department of Archaeology , University of Cape Town, Cape Town, South Africa
• ²⁹ Node for Isotope Biogeochemistry, South African Biogeochemistry Research Infrastructure Platform, Cape Town, South Africa
• ³⁰ Escuela de Ciencias del Mar, Pontificia Universidad Catolica de Valparaiso, Valparaíso, Chile
• ³¹ National Centre for Polar and Ocean Research, Arctic Biogeochemistry and Ecology, National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Goa, India
• ³² Institute for Risk and Disaster Reduction, University College London, London, United Kingdom
• ³³ Atmosphere and Climate (ATMOS), The Climate and Environmental Research Institute (NILU), Kjeller, Norway
• ³⁴ Svalbard Integrated Arctic Earth Observing System (SIOS), Longyearbyen, Norway
• ³⁵ Department of Civil Engineering, Manipal Academy of Higher Education (MAHE), Manipal, India
• ³⁶ Nansen International Environmental and Remote Sensing Center, Saint Petersburg, Russia
• ³⁷ Saint Petersburg State University, Saint Petersburg, Saint Petersburg, Russia
• ³⁸ Royal Canadian Navy, Victoria, Canada
• ³⁹ Climate Lab, University of Victoria, School of Earth and Ocean Sciences, Victoria, Canada
• ⁴⁰ OCED, AOML, OAR, NOAA, Miami, United States
• ⁴¹ CIMAS, RSMAS, University of Miami, Miami, United States
• ⁴² Harvey Mudd College, Claremont, California, United States
• ⁴³ Geography, Olabisi Onabanjo University, Ago-Iwoye, Nigeria
• ⁴⁴ Institute of Seismological Research, Gandhinagar, Gujarat, India
• ⁴⁵ Ministry of Earth Sciences, New Delhi, India
• ⁴⁶ Radiocarbon Laboratory (LAC-UFF), Department of Geochemistry, Universidade Federal Fluminense, Niterói, Brazil
• ⁴⁷ Princess Margaret Cancer Centre, University Health Network (UHN), Toronto, Canada
• ⁴⁸ Department of Business Studies, Faculty of Social Sciences, Uppsala University, Uppsala, Uppsala, Sweden
• ⁴⁹ Department of Management and Organization, Stockholm School of Economics, Stockholm, Sweden
• ⁵⁰ Departamento de Ingeniería Hidráulica y Ambiental, Pontificia Universidad Católica de Chile, Santiago, Chile
• ⁵¹ PERMACHILE network, Santiago, Chile
• ⁵² Applied Functional Ecology, Department of Plant Biology and Ecology, Universidad de Sevilla, Sevilla, Spain
• ⁵³ Bacteria physiology and genetics, Department of Life Sciences, Université de Liège, Liège, Belgium
• ⁵⁴ Protistology and Aquatic Ecology, Department of Biology, Universiteit Gent, Gent, Belgium
• ⁵⁵ UK Center for Ecology and Hydrology, Bangor, United Kingdom
• ⁵⁶ Permafrost Research Section, Department of Earth Sciences, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), Potsdam, Brandenburg, Germany
• ⁵⁷ Institute of Geosciences, Faculty of Mathematics and Natural Sciences, University of Potsdam, Potsdam, Brandenburg, Germany

The participation of a diverse –in terms of geography, discipline and gender– group of Early Career Researchers (ECRs) in the peer review process can help alleviate the workload of senior researchers and counteract the perceptual biases that the latter tend to show. Moreover, ECRs can benefit from developing skills that are often not included in educational programs. From 2018 to 2021, the Association of Polar Early Career Scientists, in collaboration with other associations, organized six group reviews of the Intergovernmental Panel on Climate Change (IPCC) reports by a total of more than 600 ECRs from over 70 different countries. This study aims to evaluate this group review in terms of its contribution to the production of scientific knowledge, and as a career development opportunity for ECRs. The data analyzed consists of application forms, review comments, and feedback surveys that were collected during each review process. The results of this study show that, overall, the group reviews were a success in terms of the experience of ECRs and their contribution to the peer review of the IPCC reports. Most survey respondents considered the general organization of the group reviews satisfactory and expressed interest in participating in future group reviews. However, most participants did not engage in discussions with their peers, which constitutes a missed opportunity to engage in active learning and the shared production of knowledge. ECRs made a significant contribution to the review of the IPCC reports by producing an average of 2422±532 comments per group review, 36% of which were substantive. PhD students were shown to be as proficient reviewers as postdoctoral researchers and faculty reviewers. More importantly, the diversity of reviewers in terms of geography and discipline, together with the fact that they are ECRs, can help produce more balanced scientific reports since they bring news perspectives, thus counteracting the biases that senior researchers have. This group reviews could be improved by providing more comprehensive training and facilitating communication among reviewers so that they can engage in meaningful exchanges. We conclude that the IPCC should formalize the inclusion of ECRs in future reviews of the IPCC reports.