ACP's publishing model combining open access and public peer review
3 September 2025
The journal Atmospheric Chemistry and Physics (ACP) successfully pioneered open-access publishing 25 years ago, making research freely accessible to everyone without paywalls or subscription barriers. In 2001, the term open access (OA) had not yet been coined – for us, it was a practical way to disseminate knowledge through a small publisher, Copernicus Publications, on behalf of the European Geosciences Union (EGU), formerly the European Geophysical Society. ACP believes that OA continues to be a force for good in scholarly publishing. It has diversified the publishing market, it has promoted equity of knowledge that benefits researchers in low-income countries, and it provides public access to publicly funded research. OA enables the authors to retain their copyright and make their research more discoverable and accessible. It also makes research reusable for the benefit of science and humanity – supporting further research, education, and the integration of scientific and public knowledge (e.g. through free online encyclopaedias like Wikipedia).
ACP went further than just open access by also opening up the peer review process so that all referee reports, editor decisions, manuscript versions, and author replies are publicly posted and permanently archived and citable. The same publishing model combining open access and public peer review is now applied by 18 other EGU journals across the whole of geoscience. Since 2001, EGU has published 50,000 journal articles and 250,000 comments from authors, referees, and the public, and public peer review has become an accepted and valued model in the geosciences.
We believe that the model of open access coupled with public peer review represents the highest standard of open science. It fosters transparency and trust in the scientific process while elevating peer review as a valued and visible part of scholarly communication. By encouraging open dialogue and constructive feedback, it enables more efficient and rigorous quality assurance. All interactions – between authors, referees, and the broader scientific community – are visible on our interactive platform, EGUsphere, reducing the risk of conflicts of interest or unprofessional behaviour. Moreover, the transparent review process serves as a valuable learning resource for early-career researchers, offering insight into scientific critique and the evolution of manuscripts – something only partially supported by standalone preprint servers or when review histories are limited to accepted journal articles. Making and keeping peer review and scientific discussion publicly accessible provides the basis for an epistemic web that reflects what we know and how well we know it.
We also believe that trust in science and scientific publishing is further strengthened when OA journals are led by learned societies. As Europe's learned society for the geosciences, EGU operates on a not-for-profit basis in the interests of the geoscience community, emphasising the dissemination of trustworthy scientific knowledge and advocating for scientific openness and academic freedom. EGU’s open-science journals therefore support and enhance these values. At the same time, EGU's scientific community plays an active role in shaping the direction of its journals, ensuring that they continue to evolve in ways that best serve the community's needs.
We recognize the concerns about open-access publishing, but we have vigorously and successfully addressed them. One concern is that the author-pays model may exclude authors from low-income countries. The fee-waiver programme of EGU journals means that no scientist in any country with an inability to pay will be excluded from publishing. For other researchers, our comparatively low article processing charges accurately reflect the true cost of handling, publishing, and ensuring permanent access to articles and their peer review history. A second concern is that OA publishing may incentivise journals to lower standards of scientific scrutiny in pursuit of revenue, which is often coupled with inducements to publish. By combining open access with transparent public peer review, EGU journals directly confront and mitigate this issue.
The world of scholarly publishing is evolving very rapidly. In response to the challenges, ACP and the other 18 EGU journals will continue to take a principled approach to publishing that remains open and responsive to the needs of the community of scientists served by the European Geosciences Union.
A full review of ACP's publishing model and its place within the evolving open-science landscape is available at Ervens et al. (2025) (https://doi.org/10.5194/egusphere-2025-419).
Ken Carslaw, Barbara Ervens, Ulrich Pöschl, and Thomas Koop
(Current and former ACP executive editors)