Coverage of climate change in introductory biology textbooks, 1970–2019

chemicals in food and household products, or genetic testing, all of which include aspects of behavioral choice. Therefore, there is precedent for students to be presented with a selection of individual behaviors with high impact on climate change. International impacts of U.S. biology textbooks This study focused on U.S. textbooks. However, the globalization of the publishing industry since the 1990s has reduced and conglomerated textbook publishing companies to the “big three:” McGraw-Hill, Pearson, and Houghton Mifflin Harcourt [34]. McGraw-Hill (North America) and Pearson Education (North America & International divisions) dominate the sci- ence textbook market. Both offer products to most countries and in scores of languages. Biology, as compared subjects such as history, culture, or language, is not limited to a nation’s borders or societal constructs. Therefore, translated biology textbooks can be distrib- uted among international audiences with few changes. Most international editions of text- books are identical in content and pagination to the U.S. versions. Therefore, we propose that our findings may be generalizable outside the U.S. textbook market. Further recommendations Education is the single strongest predictor of public awareness of climate change [35]. Climate change is also a tremendous threat to human society. Given Americans’ outsized contribution to the problem and resistance to accept anthropogenic climate change, we propose that U.S. educators or curriculum developers consider the implicit messages sent through the amount

of coverage, inclusion of subtopics, and placement of climate change information in instruc- tional materials or course organization. While textbook use has decreased in recent years, textbooks can serve as documents to ana- lyze the material presented in introductory biology courses. We recognize that student text- book usage continues to decline, yet we consider the following suggestions should apply to any instructional methods. We also acknowledge that this study is limited in content level and subject area. The topic of climate change branches beyond the sphere of science into politics, sociology, and econom- ics. In our focus on biology and college-level formal education, we may have missed other domains where young people are exposed to important lessons in climate change. We offer four recommendations to address the concerns about climate change coverage raised through this research. These recommendations also provide opportunities for further research, as any changes could be applied using experimental methods. First, we suggest that authors, publishers, and educators reconsider the standard order of topics within biology courses. Rather than starting with subcellular topics and expanding out to organismal and, finally, ecological topics, educators could start with large-scale topics and drill down to cellular processes. Alternatively, instructors could apply scaffolding to begin with organism-level content, the level at which students interact with the natural world, and then

expand to ecosystems; after revisiting the organism-level, the class could then dive into cellular and subcellular topics. Whether the standard organization is in place due to tradition or con- cern about controversy, the importance of environmental issues may require a reevaluation of the order of course topics. Second, we propose that, rather than providing extensive coverage of climate change effects with few actionable solutions, authors and educators intentionally pair effects with solutions. This allows students to focus on positive engagement with the topic of climate change, while accepting and adapting to global warming. The most extensive coverage of climate change in 2010–2019 included just 107 sentences. This content was found on 4 pages in a 1,279-page PLOS ONE Climate change in biology textbooks, 1970–2019 PLOS ONE | https://doi.org/10.1371/journal.pone.0278532 December 21, 2022 13 / 16