Agriculture is a major contributor to climate change, and there is an urgent need to reduce greenhouse gas (GHG) emissions from agriculture for mitigation purposes. Modern industrial agriculture has been recognized as a significant source of agricultural GHG emissions, whereas the adoption of regenerative organic agriculture has been proposed as a solution with the potential to reduce GHG emissions from agricultural production. However, there is a lack of on-the-ground studies reporting on the climate impacts of organic agriculture. To remedy this, a carbon footprint (CF) analysis was conducted comparing regionally representative organic and conventional arable cropping systems at Rodale Institute’s Farming Systems Trial in Pennsylvania, USA. Two separate modeling approaches were used to construct CFs for three agricultural systems (two organic and one conventional). The baseline CF analyses used an Intergovernmental Panel on Climate Change Tier 3 model (COMET-Farm) and Tier 2 model (Cool Farm Tool) for comparison purposes. Secondary analyses were conducted on the effects of CO2 emissions from composting manure on CFs. Emission metrics were generally higher (+27%) using the Tier 3 model compared with the Tier 2 model. In the baseline analysis, absolute area-scaled emissions were highest in the conventional system, ranging from 1.25 to 1.72 tons CO2-eq ha−1 yr−1. In comparison, emissions in the organic manure-based system were 25%–37% lower (0.94–1.09 tons CO2-eq ha−1 yr−1), while the organic legume-based system had the lowest emissions, which were 52%–74% lower (0.33–0.83 tons CO2-eq ha−1 yr−1). Yield-scaled emissions of maize in the baseline analyses were highest in the conventional system (0.19–0.26 kg CO2-eq kg−1), followed by the organic manure (0.13–0.16 kg CO2-eq kg−1) and organic legume (0.07–0.17 kg CO2-eq kg−1). Yield-scaled emissions on a feed digestible energy basis were highest in the conventional system (0.014–0.020 kg CO2-eq MJ−1) but were similar between organic manure (0.009–0.010 kg CO2-eq MJ−1) and organic legume (0.006–0.015 kg CO2-eq MJ−1). Including estimates of CO2 emissions due to composting increased emissions for the manure-based organic system substantially (+103%–122%). Our results imply that regenerative organic farming can help mitigate climate change. Future research should focus on more accurately measuring emissions from compost production and other sources of organic fertility, conducting a full life-cycle assessment of these systems, and verifying the results using in-situ field measurements.

Existing guidelines on overviews of reviews and umbrella reviews recommend an assessment of the certainty of evidence, but provide limited guidance on ‘how to’ apply the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) to such a complex evidence synthesis. We share our experience of developing a ‘general principles’ approach to applying GRADE to a complex overview of reviews. The approach was developed in an iterative and exploratory manner during the planning and conduct of an overview of reviews of a novel molecular imaging technique for the staging of prostate cancer, involving a formal review by a group of 11 methodologists/health services researchers. This approach was developed during the evidence synthesis process, piloted, and then applied to our ongoing overview of reviews. A ‘general principles’ approach of applying the domains of GRADE to an overview of reviews and arriving at an overall summary judgement for each outcome is presented. Our approach details additional factors to consider, including addressing both the primary study risk of bias as assessed by the included reviews and the risk of bias of the systematic reviews themselves, as well as the statistical heterogeneity observed in meta-analyses conducted within the included reviews. Our approach distilled key principles from the relevant GRADE guidelines and allowed us to apply GRADE to a complex body of evidence in a consistent and transparent way. The approach taken and the methods used to develop our approach may inform researchers working on overviews of reviews, umbrella reviews, or future methodological guidelines.

Paleontology provides insights into the history of the planet, from the origins of life billions of years ago to the biotic changes of the Recent. The scope of paleontological research is as vast as it is varied, and the field is constantly evolving. In an effort to identify “Big Questions” in paleontology, experts from around the world came together to build a list of priority questions the field can address in the years ahead. The 89 questions presented herein (grouped within 11 themes) represent contributions from nearly 200 international scientists. These questions touch on common themes including biodiversity drivers and patterns, integrating data types across spatiotemporal scales, applying paleontological data to contemporary biodiversity and climate issues, and effectively utilizing innovative methods and technology for new paleontological insights. In addition to these theoretical questions, discussions touch upon structural concerns within the field, advocating for an increased valuation of specimen-based research, protection of natural heritage sites, and the importance of collections infrastructure, along with a stronger emphasis on human diversity, equity, and inclusion. These questions offer a starting point—an initial nucleus of consensus that paleontologists can expand on—for engaging in discussions, securing funding, advocating for museums, and fostering continued growth in shared research directions.