Climate change poses many challenges that affect society and the natural world. With these challenges, however, come opportunities to respond. By taking steps to adapt to and mitigate climate change, the risks to society and the impacts of continued climate change can be lessened. The National Climate Assessment, coordinated by the U.S. Global Change Research Program, is a mandated report intended to inform response decisions. Required to be developed every four years, these reports provide the most comprehensive and up-to-date evaluation of climate change impacts available for the United States, making them a unique and important climate change document. The draft Fourth National Climate Assessment (NCA4) report reviewed here addresses a wide range of topics of high importance to the United States and society more broadly, extending from human health and community well-being, to the built environment, to businesses and economies, to ecosystems and natural resources. This report evaluates the draft NCA4 to determine if it meets the requirements of the federal mandate, whether it provides accurate information grounded in the scientific literature, and whether it effectively communicates climate science, impacts, and responses for general audiences including the public, decision makers, and other stakeholders.

This report reviews trends and progress on climate change mitigation policies in 34 OECD countries and 10 partner economies (Brazil, China, Colombia, Costa Rica, Indonesia, India, Latvia, Lithuania, the Russian Federation and South Africa), as well as in the European Union.

Ending poverty and stabilizing climate change will be two unprecedented global achievements and two major steps toward sustainable development. But the two objectives cannot be considered in isolation: they need to be jointly tackled through an integrated strategy. This report brings together those two objectives and explores how they can more easily be achieved if considered together. It examines the potential impact of climate change and climate policies on poverty reduction. It also provides guidance on how to create a “win-win†? situation so that climate change policies contribute to poverty reduction and poverty-reduction policies contribute to climate change mitigation and resilience building. The key finding of the report is that climate change represents a significant obstacle to the sustained eradication of poverty, but future impacts on poverty are determined by policy choices: rapid, inclusive, and climate-informed development can prevent most short-term impacts whereas immediate pro-poor, emissions-reduction policies can drastically limit long-term ones.

Forest land managers face the challenges of preparing their forests for the impacts of climate change. However, climate change adds a new dimension to the task of developing and testing science-based management options to deal with the effects of stressors on forest ecosystems in the southern United States. The large spatial scale and complex interactions make traditional experimental approaches difficult. Yet, the current progression of climate change science offers new insights from recent syntheses, models, and experiments, providing enough information to start planning now for a future that will likely include an increase in disturbances and rapid changes in forest conditions. Climate Change Adaptation and Mitigation Management Options: A Guide for Natural Resource Managers in Southern Forest Ecosystems provides a comprehensive analysis of forest management options to guide natural resource management in the face of future climate change. Topics include potential climate change impacts on wildfire, insects, diseases, and invasives, and how these in turn might affect the values of southern forests that include timber, fiber, and carbon; water quality and quantity; species and habitats; and recreation. The book also considers southern forest carbon sequestration, vulnerability to biological threats, and migration of native tree populations due to climate change. This book utilizes the most relevant science and brings together science experts and land managers from various disciplines and regions throughout the south to combine science, models, and on-the-ground experience to develop management options. Providing a link between current management actions and future management options that would anticipate a changing climate, the authors hope to ensure a broader range of options for managing southern forests and protecting their values in the future.

The report also provides a comprehensive assessment of past and future sea level change in a dedicated chapter.