Science is a rich process of well-informed trial-and-error and learning from errors often paves the way to scientific advances. However, this process and associated so-called null results are seldomly shared, because the publication culture and career incentives are biased towards positive results. This bias impedes scientific progress because errors or null results can be repeated by other scientists unless they are made public. In contrast, the publication of non-positive results and associated learnings completes an unbiased record of the research effort, contributes to open and transparent science, allows the authors and others to learn and may open opportunities for new science. A dedicated article type for these kinds of lessons as part of established journals clearly encourages such articles, and increases their visibility and recognition.</p> <p>Here, we introduce and explain a new article type that covers lessons learned to help overcome the positive publishing bias and that is being introduced in participating European Geoscience Union (EGU) publications. "LESSONS" articles describe the <u>L</u>imitations, <u>E</u>rrors, <u>S</u>urprises, <u>S</u>hortcomings and <u>O</u>pportunities for <u>N</u>ew <u>S</u>cience emerging from the scientific process. Note that the terms included in the LESSONS abbreviation are just examples to clarify what these article types stand for without indicating definitions or exclusive categories. Importantly, a LESSONS article will offer a substantial, valuable insight within the scope of geosciences.</p> <p>Specifically, we present two types of articles: LESSONS Reports are journal articles that apply the public peer review model of EGU's journals, whilst LESSONS Posts are not peer-reviewed preprints that allow early-stage reporting. Both article types are short, so the extent and depth to which the subject can be explored is deliberately limited (e.g., as for the <em>GC Insights</em> or <em>Letter</em> format) to help lower the barrier to journal publication. Details of how to structure and submit both of these article types are given, as well as guidance for reviewers. LESSONS articles will be published in EGU's community journals but are also summarized in a dedicated and ongoing interjournal compilation. In this way, these insights are easily findable for other scientists looking to prevent duplicate research, improve their meta-analyses, or otherwise gain value from the LESSONS articles of others.