Biodiversity and Climate Change Assessment: Review of Draft Chapters (2025)
Chapter: 1 Introduction
1
Introduction
Biodiversity is the rich variety of living things that, woven together, support and sustain life on Earth. Biodiversity has many dimensions. It encompasses genes, organisms, species, and their intricate interactions in ecosystems. It is all living things and the relationships among them, the thrumming hive of activity and connection that has been called the “fabric of life” (NASEM 2022). This diversity of life underpins healthy ecosystem structure and function and is fundamental to human well-being, providing clean air and water, climate regulation, and natural resources for cultural practices, medicine, and construction. It also provides a large economic value that spans from protecting global food security through pollination and effective fisheries management, both estimated to be in the billions of dollars (Costello et al. 2016; IPBES 2016), to wetland and floodplain areas protecting communities from flooding and avoiding damages (Johnson et al. 2020; Narayan et al. 2017), to a reduction in emergence of infectious diseases saving billions in healthcare costs and economic disruption (Dobson et al. 2020), among other benefits.
The North American region hosts an exceptionally diverse array of ecosystems (Commission for Environmental Cooperation 2024). These range from Arctic tundra in the far northern reaches of Canada and Alaska to the tropical forests in southern Mexico, encompassing vast forests, grasslands, deserts, freshwater systems, and marine environments. The region’s complex topography and climatic gradients have fostered unique assemblages of species and ecological communities, many of which have also evolved with and been shaped by Indigenous and local communities. These ecosystems transcend jurisdictions and political boundaries, necessitating coordinated conservation and management efforts across borders.
Ecosystems are experiencing unprecedented rates of change in North America and globally. Current estimates indicate that at least one million species globally face extinction risk, with significant impacts observed across North America (IPBES 2019a). Human-driven climate change is a primary driver of biodiversity loss, creating complex interactions and feedbacks (McElwee et al. 2023; Parmesan et al. 2022; Pörtner et al. 2021), with local to global impacts. Rising temperatures, altered precipitation patterns, more frequent extreme weather events, ocean acidification, sea level rise, spread of disease, and permafrost thaw are just a few of the observed impacts. At the same time, human activities have transformed over 70% of ice-free land through urbanization, agriculture, resource extraction, and infrastructure development which have provided both societal benefits and drawbacks for healthy ecosystems. These changes have fragmented habitats, polluted environments, and disrupted ecological processes essential for species survival (IPBES 2019b), adding to the complexity of understanding the intertwined nature of changes in biodiversity and climate. Current understanding of changes and connections in biodiversity and climate and influences of these other factors have been explored globally
through assessments of the Intergovernmental Panel on Climate Change (IPCC), the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), and collaborations such as the 2020 IPBES-IPCC co-sponsored workshop focused on these intertwined issues (discussed in more detail in Chapter 2 of this report).
THE BIODIVERSITY AND CLIMATE CHANGE ASSESSMENT
Building on international assessments at the global scale, the U.S. Congress allocated funding in its Fiscal Year 2022 budget for the U.S. Department of Interior to conduct a comprehensive biodiversity and climate change assessment. The U.S. Geological Survey (USGS), the science lead for the U.S. delegation to IPBES, was designated as the lead for the assessment development. Canada and Mexico expressed interest in joining and the assessment became the Biodiversity and Climate Change Assessment of North America and the U.S. Affiliated Pacific Islands (BCCA).
The BCCA is intended to provide a synthesis of knowledge and decision-relevant information that can be useful to decision-makers across multiple scales, from local resource managers to national policymakers. The assessment is intended to be used to inform policy options and solutions for biodiversity conservation in North America in the context of climate change, while remaining accessible to broader audiences involved or interested in environmental management and conservation. The BCCA authors have adopted the IPBES framework, tailored to North American contexts, incorporating IPBES principles for knowledge synthesis and policy relevance. This approach may increase compatibility with global assessment processes while addressing regionally-specific challenges and opportunities.
THIS REVIEW
At the request of the USGS, the National Academies of Sciences, Engineering, and Medicine appointed an ad hoc committee to conduct an independent expert review of the draft chapters of the BCCA. The Committee was tasked with determining whether the draft chapters adequately and transparently assess the relevant scientific literature and evidence, address the most pressing issues of biodiversity and climate change, and communicate key findings in policy-relevant language accessible to a broad audience (see the Statement of Task in Appendix A). This review is intended to provide the BCCA authors with guidance for revisions to strengthen their assessment. The review also serves as a resource to others interested in biodiversity and climate change and for future assessments that bring these topics together.
The Committee’s review began in October 2024, concurrent with the public comment period for the first order draft of the BCCA. The draft BCCA was relatively early in development when the Committee received it. Many chapters had not yet comprehensively synthesized collected information and most had not developed key findings. As a result, the Committee approached their review by first providing overarching guidance on key principles for the development of biodiversity and climate change assessments, that, if applied to the draft BCCA, would strengthen the assessment and help achieve its objectives. The Committee then developed detailed guidance for how to improve each individual draft chapter, taking into account the stage of development for each chapter.
Roadmap to this Report
In developing this review report, the Committee sought to provide constructive feedback to improve the draft BCCA. Following this introduction (Chapter 1), Chapter 2 outlines essential elements for the development
an effective biodiversity and climate change assessment, identifying areas where the first order draft of the BCCA reviewed by the Committee could be strengthened. Chapter 3 of this report then offers specific suggestions for individual draft chapters.
