All Figures

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Front Matter

1: Fifth National Climate Assessment Regions

The Fifth National Climate Assessment explores subnational climate change risks, impacts, and responses in each of the 10 regions shown.

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Chapter 1: Overview

1.1: Climate Change Risks and Opportunities in the US

Climate change presents risks while action to limit warming and reduce risks presents opportunities for the US.

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1.2: Historical Trends in Unit Costs and Deployment of Low-Carbon Energy Technologies in the United States

Increasing capacities and decreasing costs of low-carbon energy technologies are supporting efforts to further reduce emissions.

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1.3: US Adaptation and Mitigation Actions

Cities and states are acting on climate change, with a substantial increase in new activities underway since 2018.

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1.4: Future Global Carbon Dioxide Emissions Pathways

Different scenarios of future carbon dioxide emissions are used to explore the range of possible climate futures.

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1.5: US and Global Changes in Average Surface Temperature

The US has warmed rapidly since the 1970s.

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1.6: Rapid and Unprecedented Changes

Current climate conditions are unprecedented for thousands of years.

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1.7: Damages by State from Billion-Dollar Disasters (2018–2022)

The US now experiences, on average, a billion-dollar weather or climate disaster every three weeks.

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1.8: Land Surface Temperature and Its Relationship to Median Household Income for Three Cities

Lower-income urban neighborhoods experience higher surface temperatures.

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1.9: Projected Increases in Average Annual Losses (AALs) from Floods by 2050

Losses due to floods are projected to increase disproportionately in US Census tracts with higher percentages of Black residents.

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1.10: US Flooding Risks in 2020 and 2050

Increasing flooding puts more people and assets at risk.

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1.11: Exemplifying Indigenous Resilience

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1.12: Energy Employment (2020–2050) for Alternative Net-Zero Pathways

Employment gains in electrification and renewable energy industries are projected to far outpace job losses in fossil fuel industries.

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1.13: Potential Warming Pathways in the United States

When or if the US reaches a particular level of warming depends on global greenhouse gas emissions from human activities.

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1.14: Regional Changes in Climate Compared to Present-Day Conditions

What would 3.6°F (2°C) of global warming feel like in the United States?

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1.15: Consequences Are Greater at Higher Global Warming Levels

At higher global warming levels, the US will experience more severe climate impacts.

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1.16: Portfolio of Mitigation Options for Achieving Net Zero by 2050

Reaching net zero by 2050 in the US will involve a mix of reductions in greenhouse gas emissions and increases in carbon dioxide removal.

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Chapter 2: Climate Trends

2.1: Greenhouse Gas Emissions from the US and Other Sources

China is now the largest single-country emitter of carbon dioxide on an annual basis. The United States and Europe have emitted the majority of cumulative carbon dioxide.

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2.2: Observed Trends in Aerosol Optical Depth from 2002 to 2021

Trends in aerosol optical depth show decreases in aerosol pollution across the eastern United States.

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2.3: Evidence for Climate Change Across Multiple Variables

Changes across the Earth system reflect the influence of human activities on the climate.

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2.4: Observed Changes in Annual, Winter, and Summer Temperature and Precipitation

Temperature has increased and precipitation has changed over much of the United States.

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2.5: Observed Sea Level Trends

Sea levels are rising across most US coastal areas.

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2.6: Billion-Dollar Weather and Climate Disasters in 2022

The US experienced 18 billion-dollar weather and climate disasters in 2022.

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2.7: Observed Changes in Hot and Cold Extremes

Hot days have increased in the West, hot nights have increased nearly everywhere, and cold days have decreased.

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2.8: Observed Changes in the Frequency and Severity of Heavy Precipitation Events

Heavy precipitation events are becoming more frequent and intense across much of the country.

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2.9: Projected US Temperatures Changes at 1.5°C, 2°C, 3°C, and 4°C of Global Warming

The United States is projected to warm faster than the global average.

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2.10: Projected US Precipitation Changes at 1.5°C, 2°C, 3°C, and 4°C of Global Warming

Precipitation changes are projected to be larger at higher levels of warming.

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2.11: Projected Changes to Hot and Cold Extremes at 2°C of Global Warming

More hot days, even more warm nights, and fewer cold days are expected at a global warming level of 2°C.

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2.12: Projected Changes to Precipitation Extremes at 2°C of Global Warming

Increases in the frequency and severity of heavy precipitation are expected at a global warming level of 2°C.

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2.13: Projected Changes to Sea Surface Temperatures at 1.5°C, 2°C, 3°C, and 4°C of Global Warming

At higher global warming levels, sea surface temperatures are projected to change around the US coasts and open ocean, with implications for marine resources in those waters.

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2.14: Projected Global Surface Temperature Change

Future emissions of greenhouse gases determine whether and how quickly we reach 2°C of global warming.

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2.15: Possible Regional Tipping Elements

Continued warming could push some aspects of the Earth system past tipping points.

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Chapter 3: Earth Systems Processes

3.1: Observed Global Warming and Attribution to Climate Drivers

The warming observed over the industrial era was driven by emissions from human activities, with greenhouse gas warming partly masked by aerosol cooling.

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3.2: Feedbacks in the Climate System

Multiple feedback processes in the climate system amplify or partially diminish the response to radiative forcing; quantifying their values is necessary to determine the climate response to human activities.

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3.3: Advances in Understanding Climate Sensitivity and Climate Feedback

Uncertainties in climate sensitivity and feedbacks have been reduced by synthesizing multiple lines of evidence.

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3.4: SSP-Based Scenarios and Their Use in Climate Model Projections

Projections of future climate involve a multistep process using scenarios about future socioeconomic developments, policy goals, and emissions to drive Earth system models.

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3.5: Winter Surface Air Temperature Trends in Large Ensemble Simulations

Large ensemble simulations provide a plausible range of trends in winter surface air temperature combining the human-caused climate change and natural variability. The observed trend falls within the range simulated by the large ensemble for the historical period.

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3.6: Natural Variability and Climate Model and Scenario Uncertainties

The sources of uncertainty in climate projections vary depending on timescale and geographical scale and for different aspects of the climate system.

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3.7: Changes in the Contributions of Moderate and Extreme Events to Total Precipitation with Warming

As the climate warms, extreme precipitation events become more intense and make up a larger fraction of total precipitation, while moderate events become less common.

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3.8: Carbon Dioxide Sources and Sinks

While the land and ocean take up some of the carbon dioxide from human activities, the rest continues to accumulate in the atmosphere every year.

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3.9: Changes in Ocean, Cryosphere, and Coastal Processes

Climate change has multiple effects on the ocean, atmosphere, and cryosphere and their complex interactions.

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3.10: Coastal Flood Exposure

Sea level rise is increasing the probability of coastal flooding and associated impacts.

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3.11: Regional Differences in Climate Response

While temperatures have been rising almost everywhere, warming has not occurred uniformly over the planet.

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3.12: Climatic Drivers of Drought, Effects on Water Availability, and Impacts

Climate change alters the hydrologic cycle and is expected to increase drought in some regions through various process pathways.

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3.13: Consecutive Events Leading to and Resulting from Wildfires

Consecutive events caused significant human health and economic impacts in Southern California from 2012 through 2018.

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Chapter 4: Water

4.1: Water-Related Billion-Dollar Disasters in the United States

Water-related billion-dollar disasters are increasing in the United States.

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4.2: Climate Change Impacts to Water Quality

Climate change threatens the quality of freshwater supplies.

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4.3: Projected Changes in Annual Precipitation by Midcentury

Annual precipitation projections show large regional differences and a wide range of potential differences.

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4.4: Projected Changes in Annual Actual Evapotranspiration by Midcentury

Actual evapotranspiration is projected to increase across most of the Nation but decrease in the Southern Great Plains and Southwest.

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4.5: Projected Changes in Maximum Annual Snow Water Equivalent by Midcentury

Continued decreases in snowpack water content are projected across much of the US.

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4.6: Projected Changes in Average Summer (June–August) Soil Moisture by Midcentury

Projected decreases in summer soil moisture will have important implications for agriculture and ecosystems.

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4.7: Projected Changes in Annual Runoff by Midcentury

Projected changes in runoff vary across the Nation due to projected changes in multiple aspects of the water cycle.

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4.8: Climate Change Impacts to Inland Flood Drivers and Flood Activity

Climate change may cause both increases and decreases in inland flooding, depending on the location and time of year.

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4.9: Projected Changes in Annual Climatic Water Deficit by Midcentury

Water shortages to vegetation will increase across most of the Nation.

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4.10: Washington–California Snow Drought

In 2015, parts of Oregon and Washington experienced a warm snow drought while the California Sierra Nevada experienced a dry snow drought.

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4.11: Washington Apple Orchard Under Drought Stress

An apple orchard in the Roza Irrigation District in Washington shows extreme drought stress in September 2015.

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4.12: Flood Damages Associated with Precipitation Change

A portion of observed increases in inland flood damages can be attributed to changes in precipitation.

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4.13: San Pedro River, Arizona

The San Pedro River in Arizona has been depleted by groundwater pumping, drying up wetlands and wildlife habitat.

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4.14: Projected Increases in Average Annual Losses (AALs) from Floods by 2050

Losses due to floods are projected to increase disproportionately in US Census tracts with higher percentages of Black residents.

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4.15: Residential Flooding from Hurricane Harvey

Flooding from Hurricane Harvey inundated residential neighborhoods in Port Arthur, Texas.

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4.16: American Indian/Alaska Native Homes Requiring Water and Sewer System Improvements

Water infrastructure supporting Tribal and Indigenous Peoples is particularly ill-equipped to handle increases in flooding and drought.

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4.17: Resolving Water Conflicts within the Lake Ontario–St. Lawrence River System

Plan 2014 was developed to manage Lake Ontario–St Lawrence River water levels, restore ecosystems, and account for climate change.

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4.18: Natural Hydrologic Variability Influences Policy

Natural hydrologic variability can promote urgency or complacency in long-term planning.

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Chapter 5: Energy Supply, Delivery, and Demand

5.1: Climate Change Impacts on the Energy System

All aspects of the US energy system are vulnerable to the effects of climate change.

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5.2: Projected Changes in Electricity Demand

Due to climate change, electricity demand is projected to increase over this century.

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5.3: Consecutive and Cascading Events Involving the Energy System

Sequential and concurrent climate impacts have near-term and long-term effects on electricity generation and distribution.

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5.4: Potential Energy System Resilience Solutions

Many strategies are available to increase energy system resilience to climate change.

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5.5: Grid-Interactive Efficient Buildings

A reimagination of building design and operation is being driven by decarbonization goals.

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5.6: Energy System Decarbonization

Decarbonization will require innovative solutions across multiple sectors.

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5.7: Historic and Projected US Electricity Generation Sources

The Nation’s electricity grid continues to expand use of clean energy technologies.

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Chapter 6: Land Cover and Land-Use Change

6.1: Present-Day Land Cover

The United States is characterized by complex spatial distributions of developed, managed, and natural land-cover types.

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6.2: US Land-Cover Conversions, 1985–2020

Land-cover change can result from development, forest management, wildfire, and other causes.

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6.3: Expansion of Developed Land Cover

Increased development decreases natural and managed land cover.

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6.4: US Average Land Cover and Land-Cover Change

Developed land is increasing, while land with tree cover is on the decline.

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6.5: Damage from Postfire Debris Flows

Postfire debris flows threaten public safety.

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6.6: Carbon Flux Response to Land-Cover and Land-Use Change

Changes in land cover and land use affect the fluxes of carbon taken up on land or released into the atmosphere, with impacts on these fluxes lasting for decades to centuries.

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6.7: Land, Climate Change, and Ecosystem Resilience

This figure shows the primary land-use and land-cover changes, their interactions with climate, and impact on ecosystems.

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6.8: Mitigation and Adaptation Value of Future Land-Use Choices

Future land-use choices have implications for climate mitigation and adaptation.

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6.9: Scenario-Based Future Land-Use Trends

Future land-use scenarios describe a wide range of possible land-use changes in the United States.

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6.10: Possible Future Wind and Solar Power Siting

Reaching net-zero emissions will require many new wind and solar projects across the US.

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6.11: Wind Power in Agricultural Landscapes

Renewable energy generation can be sited in ways that minimize agricultural disruption.

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Chapter 7: Forests

7.1: Tree Cover Dynamics

The persistence of tree cover in the United States varies due to many driving forces.

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7.2: Estimated Annual Greenhouse Gas (GHG) Emissions from Wildfires and Prescribed Fires

The amount of forest area burned and associated greenhouse gas emissions have increased in recent decades in the United States.

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7.3: Coastal Ghost Forest

Coastal ghost forests result when trees are killed by sea level rise and saltwater intrusion.

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7.4: Very Large Fires

Conditions conducive to very large fires are projected to increase.

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7.5: Effects of Climate Change on Forests

Climate change and climate-related disturbances are affecting forests in the United States.

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7.6: Spruce and Pine Beetle Outbreaks

Outbreaks of spruce and pine beetles, partly attributable to climate change, are killing trees in the West.

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7.7: Forest Ecosystem Services

Climate change has affected the provisioning of forest ecosystem goods and services in the United States.

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7.8: Forest Carbon Sink

The forest carbon sink has declined in recent decades in the United States, with substantial interannual variability.

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7.9: Climate Effects on Forest Water Resources

Climate change and climate-related disturbances are affecting the availability and quality of water from forests in the United States.

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7.10: Climate Adaptation and Forest Ownership

Adaptation actions occur across many types of forest ownership and management in the United States.

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Chapter 8: Ecosystems, Ecosystem Services, and Biodiversity

8.1: Climate Change and Ecosystems, Biodiversity, and Ecosystem Services

Climate and non-climate stressors together affect biodiversity, ecosystems, and the services they provide.

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8.2: Regional Impacts

All US regions are experiencing impacts of climate change on species, ecosystems, and ecosystem services.

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8.3: Ecosystem Impacts and Risks

Ecosystem impacts and risks increase at higher levels of global warming.

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8.4: Amplifying Climate Change Effects on Watersheds

Climate effects on watersheds exemplify the amplifying impacts of gradual and episodic stressors.

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8.5: Tipping Points and Regime Changes

The Arctic faces substantial impacts from thawing permafrost that cannot be reversed.

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8.6: Abrupt Changes in Ecosystem State

Climate change interacts with other stressors to cause synergistic effects, and resulting ecosystem changes can be abrupt and difficult to reverse.

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8.7: Unique and Vulnerable Ecosystems

Transformations to ecosystems are already noticeable and widespread.

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8.8: Monitoring Ecosystem Changes

Monitoring programs are critically important for observing and projecting trends in resilience, species invasions, range shifts, declines, and extinctions.

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8.9: Adaptation and Transformation Planning Frameworks

Decision frameworks can help plan for the potential transformation of ecosystems.

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8.10: Extreme Event Impacts

Short-term extreme events can have severe impacts on threatened species.

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8.11: Observed Range Shifts and Changes in Phenology

Climate change is leading to shifts in phenology and range for species across the United States.

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8.12: Environmental Mosaics and Climate Refugia

Climate refugia are locations where environmental conditions are changing more slowly than in the surrounding region.

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8.13: Observed Pollinator Sensitivities

Insect pollinator responses to environmental stressors, even within the same taxonomic grouping, can vary widely.

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8.14: Threats to North Atlantic Right Whales

Climate change increases risks to the endangered North Atlantic right whale.

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8.15: Invasive Species and Climate Change

Damaging invasive species that are expected to shift in range because of climate change.

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8.16: Managing for Species Adaptation

Assisted migration can help species adapt to changing climate conditions.

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8.17: Ecosystem Services and Their Benefits

Ecosystems provide a broad range of relational benefits, from the material to the spiritual.

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8.18: Nature-Based Solutions

Nature-based solutions buffer the effects of climate change.

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8.19: Climate Mitigation Potential of Nature-Based Solutions in 2025

Nature-based solutions can support carbon storage while also providing other benefits.

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Chapter 9: Coastal Effects

9.1: Accelerating Relative Sea Level Rise in the Contiguous US

Sea level is projected to continue to increase this century by amounts related to future global warming levels.

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9.2: Projected Sea Level Rise

By 2050 and 2100 under the Intermediate sea level scenario, sea level rise is projected to be higher along the Atlantic versus the Pacific Coast and greatest along the western Gulf Coast.

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9.3: US Regional Average Flood Frequencies

Minor, moderate, and major coastal flood frequencies will increase by a factor of about 5–10 in many regions of the US relative to 2020 in the absence of adaptation.

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9.4: Existing Conditions in a Coastal Community

Coastal landscapes and man-made interventions provide economic, cultural, and community protection from existing climate hazards under existing conditions.

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9.5: Increasing Hazards in a Coastal Community

Coastal communities are expected to flood due to rising sea levels and rising groundwater levels.

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9.6: Adaptation Strategies for a Coastal Community

Timely implementation of adaptation strategies, including planned relocation, can reduce the impacts of climate change on coastal communities.

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9.7: Present and Future State of the Ohio Creek Watershed

Strategies that consider long-term community goals and inclusive and sustained engagement with frontline communities can lead to equitable transformative adaptation.

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Chapter 10: Ocean Ecosystems and Marine Resources

10.1: Ocean-Related Climate Impacts on People and Ecosystems

Many broad-scale climate-related ecological and human impacts are occurring in US marine areas.

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10.2: Northeast Pacific Marine Heatwave Impacts

The West Coast has experienced unprecedented warm ocean temperatures and environmental disruptions from marine heatwaves.

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10.3: Ocean-Based Economies

Communities throughout coastal America rely on ocean-related industries for major shares of their local economies.

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10.4: Ocean-Related Climate Adaptation Strategies

Adaptation can occur at many organizational scales—from individuals to governance systems.

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10.5: Ocean Conditions and Activities Under Two Climate Scenarios

Future ocean conditions and activities will depend on emissions levels and mitigation strategies.

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Chapter 11: Agriculture, Food Systems, and Rural Communities

11.1: Farmworker Exposure to Extreme Heat and Smoke

Climate change increases farmworker exposure to extreme heat and wildfire smoke.

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11.2: Ecosystem Services: Hub of the Wheel

Ecosystem services have wide-ranging benefits for plants, animals, and human well-being.

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11.3: Projected Changes in Plant Hardiness Zones

Plant hardiness zones are projected to shift northward throughout this century.

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11.4: Soil as a Foundation

Healthy soil plays a foundational role in agriculture, ecosystems, society, and culture.

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11.5: Agroecology Approaches and Outcomes

Agroecological approaches seek to achieve beneficial agricultural outcomes while promoting ecosystem services and rural livelihoods.

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11.6: US Agricultural Greenhouse Gas Emissions Indices, 1990 to 2020

While total agricultural greenhouse gas emissions continue to increase, emissions per capita and per unit of total factor productivity (a ratio of agricultural outputs produced to inputs used) have declined over the last 30 years.

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11.7: Cattle-Based Methane Emissions

Ruminant livestock systems contribute to US methane emissions primarily through belching.

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11.8: Greenhouse Gas Emissions from Protein Production

Greenhouse gas emissions from protein production vary greatly according to food type.

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11.9: Connections Between Climate, Food, Ecosystem, and Socioeconomic Systems

Food security is an outcome of the food system, which influences and is influenced by the climate system, ecosystems, and socioeconomic systems.

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11.10: Example Effects of Climate Change on the Food Supply Chain

Climate change has cascading and compounding effects on all stages of the food supply chain.

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11.11: Examples of Food System Failure Due to Climate Change

Climate change is expected to increase risks to food security in multiple ways.

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11.12: Greenhouse Gas Emissions by Food Supply Chain Stage

Greenhouse gas emissions differ by stage of the food supply chain.

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11.13: Community Resilience Index

Rural communities differ in the categories of the Baseline Resilience Indicators that contribute most substantially to their resilience.

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11.14: Baseline Resilience Indicators for Communities

Rural community resilience to natural hazards is measured by several broad categories of indicators that affect aspects of resilience (both positively and negatively).

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Chapter 12: Built Environment, Urban Systems, and Cities

12.1: Greenhouse Gas Emissions by US County and Affiliated Territories

Urban and suburban areas contribute the majority of total greenhouse gas emissions through their consumption and populations.

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12.2: Urban and Rural Population Trends

Urban areas constitute a significant majority of the total US population in all future scenarios.

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12.3: Examples of Built Environment Types Found in US Cities

Cities across the US include multiple types of built environments, ranging from dense urban cores to much less dense suburbs.

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12.4: Effects of the Built Environment on Local Temperatures

Different aspects of the built environment affect temperatures in urban areas.

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12.5: The Urban Heat Island Effect

Urban heat islands are most prominent in dense downtown areas with little access to open space.

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12.6: Land Surface Temperature and Its Relationship to Median Household Income for Three Cities

Lower-income urban neighborhoods experience higher surface temperatures.

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12.7: Natural Infrastructure in Cities

Natural infrastructure in cities provides climate mitigation and adaptation benefits.

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12.8: Green, Blue, and Nature-Based Solutions

Cities have diverse options for climate adaptation and mitigation.

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12.9: Social, Ecological, and Technological Components of Infrastructure

Urban infrastructure involves joint social, ecological, and technological systems. All face risks from climate change individually and in interconnected ways.

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Chapter 13: Transportation

13.1: 2021 Greenhouse Gas Emissions from US Domestic Transportation by Mode

Transportation remains the largest source of emissions in the US, with cars and light-duty trucks as the largest contributors.

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13.2: Transportation Future

A shifting transportation landscape, and how we respond to it, will determine future climate outcomes.

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13.3: Resilience Planning Cycle

Improving transportation resilience requires an iterative approach.

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13.4: Co-benefits of Mitigation and Resilience

Decarbonizing transportation could save money and improve air quality, social equity, and the health of people and ecosystems.

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13.5: Considerations of Equitable Climate Adaptation and GHG Mitigation from Transportation Systems

Reducing emissions involves trade-offs that have implications for reliability, equity, and environmental quality.

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Chapter 14: Air Quality

14.1: Climate Change Impacts on Ozone and Fine Particulate Matter PM_2.5 over the United States

Climate change will have varying effects on ozone and fine particulate matter (PM_2.5) concentrations, including through impacts on weather-sensitive emissions.

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14.2: Simulated Historical and Projected Changes in Fine Particulate Matter (PM_2.5) and Ozone

Reductions in human-caused emissions that contribute to ozone and fine particulate matter (PM_2.5) are expected to improve air quality in a changing climate.

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14.3: Impacts of Wildfire Smoke on Air Quality

Wildfire smoke affects air quality across the country.

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14.4: Air Pollution Exposure at Home in the Houston Ship Channel Region

Industries expose people living near the Ship Channel—often African American, Latino, and low-income residents—to harmful air pollution.

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14.5: Air Pollution and Temperature Inequalities in Houston, Texas

Air pollution, its health impacts, and temperatures are unequally distributed across Houston, Texas.

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14.6: Observed and Projected Pollen Changes Under Climate Change

Pollen has been increasing in many US regions and is projected to continue to increase as climate changes.

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14.7: Potential for Emissions-Reduction Actions to Achieve Air Quality and Climate Benefits

Many emissions-reduction actions can achieve multiple benefits for climate, air quality, and health.

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14.8: Air Quality and Health Benefits Estimates in the US, Relative to Costs

Air quality health benefits alone exceed or significantly offset the costs of greenhouse gas reductions.

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Chapter 15: Human Health

15.1: Heat and Health Equity

Heat does not impact all communities equally.

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15.2: Regional Examples of Climate-Sensitive Infectious Diseases

Some climate-sensitive infectious diseases are expected to see expanded geographic range and extended seasonality.

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15.3: Children’s Mental Health

Out of 1,000 children and young people surveyed in the US, a majority expressed worry about climate change impacts to people and the planet.

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15.4: Intergenerational Inequity

The number of climate hazards a person born in North America will experience during their lifetime depends on how much Earth warms above preindustrial levels

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15.5: Social Vulnerability and Climate Hazards

Some highly vulnerable areas also have high economic losses from climate hazards.

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15.6: Indigenous-Led Disaster Recovery Actions and Improved Health Outcomes

Louisiana Tribal leaders are upholding sovereignty and self-determination in their climate adaptation actions following hurricane damage.

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Chapter 16: Tribes and Indigenous Peoples

16.1: Representative Locations of Indigenous Peoples

Homelands of Indigenous Peoples are located throughout the US and its territories.

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16.2: The Complexity of Land Tenure for Indigenous People

Federally Recognized Tribal Lands are often near federal lands, where Indigenous Peoples may have consultation, treaty, or comanagement rights.

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16.3: Indigenous Holistic Worldview

Indigenous holistic worldviews offer diverse and complex expressions of climate change.

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16.4: Tribal Renewable Energy Projects

The breadth of project type and funding amounts have increased for federally funded renewable energy projects.

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16.5: Publicly Available Climate Data in Relation to Indigenous Territories

Some tribal lands are vulnerable to floods, wildfire, and drought.

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16.6: Indigenous Ingenuity the Hopi Way

Actions on climate change taken by the Hopi people engage science, tradition, and education.

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16.7: Tsha’ Thoñswatha’ Firehouse and Community Hall

The Tsha’ Thoñswatha’ firehouse and community hall in the Onondaga Nation relies on renewable energy and meets a net-zero standard of energy use.

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16.8: Climate initiatives at College of Menominee Nation

At the College of Menominee Nation, Indigenous Knowledge guides climate change response.

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Chapter 17: Climate Effects on US International Interests

17.1: Interconnected Interests and Cascading Impacts

Future impacts to US interests are uncertain given complex system interdependencies and interactions between stressors, capacities, and responses.

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17.2: US Net Import Reliance by Region for Minerals Necessary for Renewable Energy Technology

US renewable energy technologies rely on imports of critical minerals from around the world.

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17.3: Climate-Related Disasters and Economic Losses

This figure shows global trends in the number, growing costs, and increasing diversity of types of climate-related natural disasters since 2000.

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17.4: Climate Finance

Public and private contributions to global climate finance are increasing but not at the pace necessary to avoid the worst impacts of climate change.

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17.5: Impact of Climate Change on Mortality Rates in 2050

Climate change will exacerbate global inequalities in mortality rates.

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Chapter 18: Sector Interactions, Multiple Stressors, and Complex Systems

18.1: Interacting and Overlapping Features of Human–Natural Systems

Climate-related experiences and actions connect with many other activities and contexts.

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18.2: Intersectional Vulnerabilities

Intersecting social and environmental factors privilege some people’s ability to respond to climate change.

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18.3: Interacting Climate Responses and Knowledges Across Scales

Climate responses, ranging from the individual to global scale, interact with and draw from diverse knowledges.

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18.4: Governance of Complex Systems

Governing complex systems involves pathways of decision-making across time.

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Chapter 19: Economics

19.1: Example Projected US Economic Damages for 3°F of Global Warming

Projected economic impacts of climate change vary by sector and region, with aggregate impacts resulting in net damages nationally.

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19.2: Climate Damages by Income, Age, Access to Credit, and Race and Ethnicity

The effects of weather and climate change are often experienced differently by populations according to income, age, access to credit, and race and ethnicity.

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19.3: How Climate Hazards Impact Real Estate Prices

Exposure to climate hazards has a negative effect on real estate values.

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19.4: Fiscal Risks of Climate Change

Climate change puts pressure on public budgets.

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19.5: The Social Cost of Greenhouse Gases

The social cost of greenhouse gases is a monetary estimate of the total economic impact of an additional greenhouse gas emission today.

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Chapter 20: Social Systems and Justice

20.1: Three Dimensions of Environmental Justice

Environmental justice requires three dimensions: recognitional, distributional, and procedural justice.

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20.2: Climate Change Governance

Climate change governance is complex and multifaceted.

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20.3: Coproduction in Research

Coproduction is a way forward to include multiple epistemologies, or knowledge traditions, but must be defined to be productive.

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20.4: Successful Climate Engagement

A simple three-step process of communication can improve climate change engagement with diverse stakeholders.

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20.5: Migration and Governance

Social systems create just or unjust conditions that influence migration outcomes.

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20.6: Relocation and Tribal Sovereignty

Quinault Indian Nation engaged the full community in its village relocation plan.

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Chapter 21: Northeast

21.1: Trends in Extreme Precipitation in the Northeast

The number of days in the Northeast with extreme precipitation has increased.

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21.2: Examples of State and Local Responses to Extreme Weather

Northeastern states and cities have adopted a range of plans, programs, and policies in response to extreme weather, many of which include nature-based strategies.

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21.3: Northeast US Newspaper Mentions of Extreme Weather and Nature-Based Solutions

Mentions of extreme weather events and nature-based solutions are increasing across Northeast media.

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21.4: Ocean Temperatures and Marine Heatwaves

Oceans are growing warmer and marine heatwaves are more frequent, which is impacting marine ecosystems in the Northeast.

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21.5: Past (1985), Present (2015), and Future (2050) of the Gulf of Maine Ecosystem

Shifts in the abundance and composition of species in the Gulf of Maine are expected to continue with additional warming.

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21.6: Changing Distribution of Fishery Resources in the Northwest Atlantic Ocean

The distribution and abundance of American lobster are expected to decrease by midcentury.

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21.7: Projected Changes in Coastal Forests

Rising sea levels kill trees and transform coastal forests into marshes, damaging vital ecosystems and the services they provide to the community.

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21.8: Summer Temperature Differences by Neighborhood in the Bronx, New York

Average summer temperatures are generally higher in historically redlined neighborhoods in the Bronx, New York.

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21.9: Flood Insurance Take-Up Rates by County

Many Northeast households and communities risk financial hardship from a lack of flood insurance coverage.

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21.10: Public Funding for Resilience

Northeastern states provide funding for resilience efforts in a number of ways.

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Chapter 22: Southeast

22.1: Population Change in the Southeast

Population change in the Southeast exposes more people to climate threats along the coast and in cities while leaving rural areas with limited capacity.

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22.2: Land-Cover Change and Biodiversity

Land cover change and sprawling development threaten unprotected biodiversity hotspots in the Southeast.

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22.3: Billion-Dollar Disasters and Hurricanes in the Southeast

The Southeast frequently experiences costly weather-related disasters, which are worsened by climate change.

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22.4: Current and Projected Risks to Homes

Vulnerable homes in the Southeast will face increasing climate threats in the future.

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22.5: Sea Level Rise and Flooding in the Southeast

Major flood events in Jacksonville, Florida, could become about 5 times more likely by 2050 under an Intermediate-High sea level rise scenario.

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22.6: Climate-Resilient Neighborhood Design

Climate-resilient community design can ensure the long-term vitality of cities.

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22.7: Climate Resilience in the Southeast

Southeast communities are adapting to climate threats in a number of ways.

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22.8: Present-Day Health Inequities

Present-day health inequities in the Southeast exacerbate climate-related risks.

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22.9: Inequitable Heat Burden and Future Heat Exposure

Projected increases in heat extremes disproportionately affect communities of color and other energy-burdened groups.

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22.10: Blackouts Affecting More than 1,000 Residents for More than 1 Hour

Warm-season blackouts add to heat-related risks for residents in Southeast.

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22.11: Current PM_2.5 Levels and Projected Change in Deaths due to PM_2.5 at 2°C of Global Warming

Rising levels of air pollution from a warming climate pose profound threats to human health.

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22.12: Household Income and Rural Capacity for Action

Counties where low-income households overlap with limited community capacity (shown in light gray) highlight rural climate risk challenges.

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22.13: Projected Annual Economic Damages from Unmitigated Climate Change

The Southeast region faces substantial economic risks from climate change impacts.

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22.14: Regional Impacts of Extreme Weather Events

The Southeast is impacted by a wide variety of extreme weather events.

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22.15: Proactive Adaptation Offsets Future Transportation Infrastructure Costs

Proactive adaptation to climate change could save millions of dollars in future transportation infrastructure costs.

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22.16: Expected Impacts of an Unplanned Calcasieu Navigation Lock Closure

An unplanned closure of the Calcasieu Navigation Lock would have impacts that extend well beyond the Southeast.

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22.17: Projected Annual Energy Infrastructure Costs

Proactively investing in strengthening our electrical infrastructure offsets significant future costs due to climate change damage.

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22.18: Droughts and Black Farmers in the Southeast

The Southeast’s Black farmers face disproportionate weather and climate risks.

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22.19: Projected Changes in Agricultural Yields Under Unmitigated Climate Change

Agricultural yields are expected to decrease under very high warming.

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22.20: Rivercane in North America

Rivercane, a native bamboo, is culturally important to many Tribes in the Southeast.

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Chapter 23: US Caribbean

23.1: The US Caribbean

The US Caribbean region in the Fifth National Climate Assessment consists of Puerto Rico and the US Virgin Islands.

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23.2: Temperature and Rainfall in Puerto Rico

Puerto Rico is projected to become warmer and drier, with increasing uncertainty in the magnitude of change beyond midcentury; just how warm and dry depends on the scenario followed.

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23.3: The One Health Approach

In the face of climate change, the health of Caribbean people, plants, animals, and ecosystems depends on coordination across multiple scales and boundaries.

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23.4: Climate Change and Public Health

Public health is shaped by sociocultural factors and further affected by climate change.

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23.5: Excess Mortality from Hurricane Maria in Puerto Rico

Excess mortality from Hurricane Maria was most common among Puerto Rico’s most impoverished residents.

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23.6: Annual Expected Benefits from Coral Reefs in the US Caribbean

Coral reefs provide substantial coastal protection benefits to the US Caribbean each year.

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23.7: Ecosystem Stressors

Both climate and non-climate stressors affect aquatic and terrestrial ecosystems and biodiversity in the US Caribbean.

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23.8: Climate Impacts on Food and Water Systems from Ridge to Reef

Risks to food and water systems differ under wet and dry scenarios.

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23.9: Food and Water Systems

Cascading impacts of climate change affect food and water systems and security.

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23.10: Infrastructure at Risk of Flooding in the US Virgin Islands

Many types of facilities in the US Virgin Islands and Puerto Rico are threatened by storm-induced flooding.

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23.11: Decentralizing Infrastructure and Governance

Strengthening the resilience of infrastructure will require a transition to decentralized systems as well as decentralized modes of governance.

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23.12: Status of Adaptation Action

Adaptation action in Puerto Rico and the US Virgin Islands reflects different starting times and available capacity.

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Chapter 24: Midwest

24.1: Change in Frequency of Transitions Between 1-Month Precipitation Extremes

The frequency of wet–dry and dry-wet transitions across the Midwest is projected to increase by late century (2071–2100).

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24.2: Freeze-Damaged Apple Blossoms

Early warmth and flowering followed by freezing temperatures in the spring poses risks to perennial and annual crops.

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24.3: Trends in Last Freeze Dates for Spring

Last spring freezes are occurring earlier over most of the Midwest region.

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24.4: Environmental Impacts from Conventional Versus Climate-Smart Practices

Climate-smart agricultural strategies may have adaptation and mitigation advantages that balance agricultural needs and environmental impacts.

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24.5: Extreme Precipitation Impacts

Extreme precipitation events have adverse impacts on aquatic and terrestrial ecosystems, human health, infrastructure, and economies. Conservation and management strategies can help moderate these impacts.

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24.6: Ecological Services of Ice-Covered Inland Waters

Rising winter temperatures are decreasing inland lake ice cover and the associated ecosystem services, benefits, and activities it provides.

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24.7: Impacts from Wildfire Smoke in the Midwest

Wildfire smoke from both local and distant sources threatens human health.

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24.8: Midwest Region Lyme Disease Case Counts by State (2000–2019)

Lyme disease incidence has increased across the Midwest.

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24.9: Beneficial Use Wetland Creation for Healthy Ports

Innovative design of coastal infrastructure, such as the Ashtabula Port, allows the built environment to deliver social and environmental services.

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24.10: Climate Change–Related Factors in Dam Failure

Climate change–related factors contribute to dam failure, with cascading impacts on the built environment.

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24.11: Projected Changes in Cumulative Seasonal and Annual Local Runoff

Projected changes in cumulative local runoff will lead to increased flooding susceptibility in winter and spring, with increased flash drought potential in summer.

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24.12: Map of US Aquifers

Vulnerability to disruptions in water quality and quantity varies by location, depending on the primary source of water for drinking and other uses.

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24.13: Great Lakes Summer Surface Water Temperature Trends

Summer surface water temperatures have been increasing for Lakes Superior, Michigan, Huron, and Erie since the late 1970s.

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Chapter 25: Northern Great Plains

25.1: Tribal Lands and Rurality Measures

Rural areas, including those controlled by Indigenous Peoples, are often under-resourced and therefore less resilient to climate change.

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25.2: Annual Precipitation for the Northern Great Plains

The region has distinct east–west precipitation gradients.

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25.3: Temperature for the Northern Great Plains

Distinctive gradients of temperature will hold with projected warming.

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25.4: Water Resource Regions and Rivers

Annual peak streamflow—a proxy for flooding—has been rising in eastern portions of the region and declining in the west.

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25.5: Observed and Projected Potential Evapotranspiration

Warming is expected to increase evapotranspiration.

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25.6: Observed and Projected Soil Moisture

Warming may not always lead to declines in soil moisture that would cause water stress in crops and natural plants.

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25.7: Invasive Species as Bioindicators of Ecological Condition

Invasive cool-season grasses are reducing biodiversity in the Northern Great Plains.

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25.8: Geography of Land Use and Social Vulnerability

The Northern Great Plains region shows wide geographical variations in land use and social vulnerability.

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25.9: Land-Use Conversion as a Strategy for Climate Adaptation

Land-use conversion offers one strategy for adapting to climate change.

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25.10: Marginal Farmland Planted to Switchgrass

Conversion of cropland to production of biofuels such as switchgrass is being piloted in the region as a climate adaptation action.

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25.11: Pattern Field Tiling

Draining agricultural fields through tiling improves crop yields but can harm ecosystems.

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25.12: Adaptation Planning

Scenario-based planning accounts for uncertainty by considering a range of ways in which change might occur.

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Chapter 26: Southern Great Plains

26.1: Annual Number of Days with Precipitation of 2 Inches or More (1900–2021)

The frequency of days with precipitation of 2 inches or more has increased across the Southern Great Plains.

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26.2: Historical and Projected Changes in Air Temperature (1900–2100)

Air temperatures for Kansas, Oklahoma, and Texas are projected to be historically unprecedented by the end of the century.

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26.3: Compounding Damages in Houston, Texas, from a Hurricane, Cold Outbreak, and Pandemic

Damages from compounding events—a hurricane, cold outbreak, and pandemic—disproportionately impacted socially vulnerable populations in Houston, Texas.

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26.4: Resilience Actions to Address the Impacts of More Frequent or Severe Droughts on Communities

Resilience actions can help alleviate harmful consequences to communities of more frequent or severe drought.

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26.5: Methane Across the Permian Basin (May 2018–March 2019)

Natural gas operations in the Permian Basin leak large amounts of methane.

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26.6: Net Generation of Electricity from Wind (2001–2022)

The Southern Great Plains contributes a large share to total US wind-generated electricity.

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26.7: Power Generation Outages During the Cold Outbreak in February 2021

A severe cold outbreak in February 2021 led to extensive outages for electricity generation plants serving the Electric Reliability Council of Texas (ERCOT).

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26.8: Income and Racial/Ethnic Disparities Related to Power Outages in Texas, February 2021

Regardless of income level, non-White populations experienced a disproportionate share of outages during the February 2021 cold outbreak.

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26.9: Projected Change in Annual Risk of Late False-Spring Events

The risk of plant bud burst before the last freeze is projected to increase for the northern portion of the Southern Great Plains. The risk decreases for the southern portion of the region.

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26.10: Projected Change in Total Annual Precipitation

Slightly drier conditions are projected for much of the western and southern portions of the region by the end of the century.

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26.11: Resilience Actions to Address the Impacts of Heavier Rainfall Events on Businesses

Resilience actions can help businesses and industries reduce the negative consequences of more heavy rainfall events.

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26.12: Climate Change Impacts on Outdoor Activities

Climate change is expected to affect many outdoor sports, recreational, and leisure activities.

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26.13: Projected Change in Annual Number of Days of 100°F or Higher

The number of extreme-heat days is projected to increase.

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26.14: Extreme Event Impacts on Sports and Recreation

Outdoor sports and recreation of all kinds are challenged by extreme events.

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26.15: Flooding of Park in Kansas, Spring 2019

Historic spring flooding in 2019 closed parks and recreational areas in southeastern Kansas.

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26.16: Resilience Actions to Address the Impacts of Hotter Summer Temperatures on Outdoor Activities

Resilience actions can alleviate the effects of hotter temperatures on outdoor activities.

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26.17: Increased Climate Risks in Port Arthur, Texas

Historically underserved communities near chemical facilities face increased risks from weather hazards associated with climate change.

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26.18: Collaboration to Develop Tribal Climate Adaptation Plans

Nine Tribes of Kansas, Nebraska, and Iowa work together to create customized climate action plans for their individual communities.

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26.19: Resilience Actions to Address Equity and Justice Issues Related to Increasing Hurricane Risk

Resilience actions centered on justice and equity can help overburdened communities respond to increasing hurricane risks.

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26.20: Extreme Rainfall Impacts on Transportation

Heavy downpours associated with Hurricane Harvey (2017) caused bridge damage.

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26.21: Mitigation and Adaptation Actions Across the Southern Great Plains

A wide array of actions are being conducted across the region to address the impacts of climate change.

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26.22: Water Treatment Plant in Norman, Oklahoma

Wastewater treatment services in the region are addressing water resource challenges.

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26.23: Resilience Actions to Address the Impacts of Severe Winter Storms on Public Services

Resilience actions can reduce risks to public services caused by increasingly variable severe winter storms.

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Chapter 27: Northwest

27.1: Atmospheric Rivers and Extreme Precipitation in the Northwest

Extreme precipitation days are closely associated with atmospheric rivers, which are projected to be more frequent and intense and to reach farther inland.

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27.2: Redlining and Extreme Heat in Portland, Oregon

Economically and racially segregated urban communities are inequitably exposed to climate change impacts, including extreme heat.

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27.3: Climate-Related Impacts and Extreme Events to Northwest Ecosystems

Long-term climate changes and extreme events threaten Northwest ecosystems.

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27.4: Interacting Stressors Affect Salmon Resilience

Stressors stemming from interactions between human activities and natural systems affect freshwater and marine ecosystems and reduce salmon resilience to climate change.

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27.5: Agricultural Losses Through Crop Insurance Indemnity Payments

Increasing trends in crop insurance loss payments reflect the economic disruption of agricultural production due to extreme events including droughts.

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27.6: Annual Cooling Degree Days Relative to Annual Hydropower Generation

Hydropower generation is currently meeting the number of cooling degree days but might not continue to do so as temperatures and heatwaves increase in the future.

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27.7: Carbon Dioxide Emissions from Fossil Fuels by State and Sector

Carbon dioxide emissions from fossil fuel consumption vary widely by sector and state.

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27.8: Heat-Related Emergency Room Visits for Health and Human Services (HHS) Region 10

Heatwaves, such as the heat dome event in the summer of 2021, place strains on healthcare systems.

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27.9: Projected Asthma Burden per Wildfire Season in 2050

Excess asthma burden associated with wildfire smoke is expected to disproportionately affect the Northwest.

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27.10: Heritage, Sense of Place, and Amenities at Risk

The heritage of the Northwest is intertwined with the diversity of landscapes, economies, and quality of life.

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27.11: Growth in Wildland–Urban Interface (1990–2020)

The growth of homes in the wildland–urban interface puts an increasing number of people at risk of wildfire and flooding.

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Chapter 28: Southwest

28.1: Climate Change Indicators, Impacts, and Responses in the Southwest

Indicators highlight important climate impacts and adaptation and mitigation efforts.

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28.2: Projected Changes in Soil Moisture, Snow Water Equivalent, and Runoff

Climate change is projected to reduce snow water equivalent and alter trends in soil moisture and annual runoff.

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28.3: Satellite Images of Lake Mead

Lake Mead water levels have declined, with potential water supply implications for millions of people.

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28.4: California Marine Heatwaves

Pacific marine heatwaves have had coast-wide impacts on ecosystems and fisheries.

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28.5: Sea Level Rise Risks to Infrastructure and Communities

Flooding from sea level rise is expected to affect transportation infrastructure and communities along the California coast, with disproportionate impacts on lower-income communities.

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28.6: Agriculture and Climate Change in the Southwest US

Monitoring indicators of climate impacts on agriculture can improve understanding and help with adaptation efforts.

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28.7: Heat Impacts in the Southwest

With extreme heat events expected to increase in frequency and severity, the ability to perform work outside is projected to decline across parts of the Southwest.

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28.8: Community Resilience Estimates for the Southwest

Communities with higher socioeconomic risk factors are expected to be less resilient in the event of climate and weather disasters.

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28.9: Wildfire and Vegetation Change in the Southwest

Climate change is leading to larger and hotter fires and resulting in shifts in vegetation.

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Chapter 29: Alaska

29.1: Recent Climate-Driven Extremes and Notable Events

Climate-driven extreme events continue throughout Alaska.

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29.2: The Context of Climate Change Response

The response to climate change depends on the desired societal outcome and is shaped by existing societal and environmental conditions.

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29.3: Climate, Health, and Well-Being in Communities

The impacts of climate change on health and well-being depend on many social and environmental factors.

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29.4: Gladys I’yiiqpak Pungowiyi

Strong connections between individuals and communities are vital in rural Alaska.

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29.5: Racial and Geographic Distribution of Alaska’s Population

The racial makeup and population density of Alaska's communities vary greatly by region, creating the potential for varied exposures and disparate impacts across subpopulations

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29.6: Cross-Section of Snowpack After the December 2021 Storm

A rain-on-snow event in December 2021 blocked roads and caused other damages.

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29.7: Climate-Sensitive Employment in Alaska

Climate change is expected to have wide-ranging effects on key economic sectors in Alaska.

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29.8: Unloading Salmon Sent to Chignik in Response to the Fishery Disaster

Donations of salmon provided much-needed food to Chignik and other small communities.

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29.9: Coastal Erosion Rates and Processes in Alaska

Coastal erosion is a major threat around Alaska.

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29.10: Pretty Rocks Landslide, Denali Park Road

Thawing permafrost limited access to Denali National Park.

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29.11: Major Recent Ecological Changes

Climate change has caused or contributed to extensive ecological effects throughout Alaska in recent years.

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29.12: Chinook Salmon Research

Research on the effects of heat on salmon can help scientists understand the effects of continued warming.

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29.13: Climate Change Risks to Military Installations

Climate change poses risks to military assets in Alaska.

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29.14: Canned Red Salmon in Port Heiden

Salmon is vital for food security in much of Alaska.

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29.15: Climate Threats Across Alaska

Statewide assessments show extensive climate-related threats throughout Alaska.

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29.16: Navigating Diverse Institutions to Meet Local and Regional Priorities

Adaptation is a complex process, requiring expertise and engagement with multiple entities.

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29.17: Harvesting Kelp in Prince William Sound

Kelp farming is an adaptation action that can reduce the impacts of ocean acidification, take up carbon dioxide, and provide income.

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Chapter 30: Hawai'i and US-Affiliated Pacific Islands

30.1: Hawaiʻi and the US-Affiliated Pacific Islands

Hawaiʻi and the US-Affiliated Pacific Islands span a vast geography.

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30.2: Detailed View of Hawaiʻi and the US-Affiliated Pacific Islands

The Pacific Islands region contains a diversity of high and low islands.

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30.3: Projected Changes in Rainfall at 3°C (5.4°F) of Global Warming (Relative to 1985–2014)

Rainfall is projected to increase across most of the region with 3°C (5.4°F) of global warming.

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30.4: Regional Sea Level Rise Projections

Future sea levels strongly depend on the scenario, and rates will vary across the region.

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30.5: Climate Change Indicators and Impacts in the Pacific Islands

Monitoring key indicators of climate change is essential for understanding impacts and informing adaptation efforts.

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30.6: Traditional Cast Net Fishing

Species loss threatens the traditions, livelihoods, and resilience of Pacific Islanders.

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30.7: Key Agricultural Plants: Giant Swamp Taro

Programs aimed at supporting traditional crops help strengthen food security.

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30.8: Damage from Typhoon Yutu

Extreme events acutely affect Pacific Island communities and their built environment.

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30.9: Oʻahu Community Heat Assessment (August 31, 2019)

High temperatures are responsible for heat-related illnesses, hospitalizations, and death.

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30.10: Coastal Flooding Events

Sea level rise is increasingly impacting infrastructure and communities.

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30.11: Annual Risk Reduction Benefits Provided by Coral Reefs

Coral reef degradation could affect thousands of people and cause millions of dollars in damages.

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30.12: Characteristic Ecosystems of the Pacific Islands

Pacific Island marine environments provide the foundation for local food systems and cultures.

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30.13: Wildfire Area Burned in the Pacific Islands Compared to the Western US

Wildfires burn large percentages of land in Pacific Islands compared to the western US.

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30.14: The Climate Urgency of Pacific Island Conservation

Conservation efforts across the region help to restore ecosystem health and protect native species.

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30.15: Restoring and Caring for Hawaiian Limu (Seaweed)

The resilience of Pacific Island communities is strengthened by their connection to place and all of its life-forms.

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30.16: Climate Change Impacts on Cultural Sites

Cultural sites, representing the living culture and ancestral knowledge of Indigenous Peoples, are at increasing risk.

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Chapter 31: Adaptation

31.1: Number of Publicly Documented Adaptation Activities (2018–2022)

The level of documented public- and private-sector adaptation activity varies widely across US states and territories.

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31.2: Adaptation Actions Defined by Multiple Factors

Adaptation outcomes are the result of individual and group values and decision-making processes and constraints.

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31.3: Incremental vs. Transformative Approaches

Incremental and transformative adaptation may take many forms, but incremental adaptation involves small changes while transformative adaptation involves profound shifts.

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31.4: Organizations and Actors Involved in Adaptation Governance

Climate adaptation involves numerous actions by different actors at multiple jurisdictional scales.

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31.5: Estimated Annual Change in Costs Due to Climate Change

Future costs associated with climate change will depend on adaptation efforts and scenarios.

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Chapter 32: Mitigation

32.1: US Greenhouse Gas Emissions by Sector with 2030 and 2050 Goals Added

US emissions will need to decrease rapidly to reach levels consistent with international climate targets.

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32.2: Changes in Drivers for Energy-Related Greenhouse Gas (GHG) Emissions

US greenhouse gas emissions have dropped even as population and economic activity (as measured by GDP) have climbed.

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32.3: Trends in Electricity Generation by Source and Related CO₂ Emissions

Carbon dioxide (CO₂) emissions from electricity generation decreased by almost 40% between 2005 and 2020.

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32.4: Trends in Transportation Emissions and Underlying Drivers

Transportations emissions fell from 2007–2012 but have climbed since then.

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32.5: Trends in Residential- and Commercial-Building Emissions and Intensities

Overall greenhouse gas emissions from buildings have climbed despite small declines in CO₂ emissions from onsite combustion of fossil fuels.

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32.6: Trends in Industry Emissions

Greenhouse gas emissions from US industry, including manufacturing, have declined in recent decades.

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32.7: Trends in Land-Use Greenhouse Gas Emissions and Underlying Drivers

US forests sequester more carbon than is emitted by agriculture, but the forest sink has weakened in recent decades.

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32.8: Historical Trends in Costs and Capacity of Low-Carbon Energy Technologies in the United States

Costs of renewable energy sources and electric vehicle batteries have declined as their cumulative deployment has increased.

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32.9: Historical and Projected Net-Zero Annual Capacity Additions by Technology for the US Under Net-Zero Scenarios

To reach net zero, the US will need to add more electricity-generating capacity in each of the next 30 years than we have added historically.

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32.10: Projected Coal and Solar/Wind Electricity Generation

Models project a steep decline in coal-generated electricity and increases in renewables.

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32.11: Characteristics of US Energy Systems in Climate Mitigation Scenarios

Net-zero model scenarios show large increases in electrical energy, accompanied by decarbonization of electricity sources and modest decreases in overall energy use per person.

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32.12: Emissions Reductions and Related Health Benefits from Dietary Shifts

Changes in American diets could decrease US land-use greenhouse gas emissions, increase carbon sequestration, and reduce air pollution.

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32.13: Hydrogen Production by Source and End Uses in 2021 and 2050

Energy model scenarios show that the magnitude, sources, and uses of hydrogen will change substantially by 2050.

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32.14: Scale and Type of Carbon Dioxide Removal in US Net-Zero Emissions Scenarios

Net-zero emissions scenarios project substantial carbon dioxide removal by 2050, although the type and quantities used in the scenarios vary considerably.

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32.15: Health Co-benefits of Strategic Power Plant Retirements

Shutting down coal-fired power plants would produce both health and climate benefits.

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32.16: Land and Water Requirements of Energy Sources

Different sources of energy entail more or less water and land use.

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32.17: Energy Employment from 2020 to 2050 for Alternative Net-Zero Pathways

A shift toward renewables is projected to increase the total number of jobs in the energy sector.

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32.18: Inequitable Air Quality Within Historically Redlined Neighborhoods

Communities redlined in the 1930s experience more air pollution today.

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32.19: Increasing Reliance on Imported Nonfuel Minerals

The US has grown increasingly dependent on imported minerals.

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32.20: Mitigation-Related Activities at the State and City Levels

Many states and cities have taken action to reduce greenhouse gas emissions.

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32.21: Adoption Rate of Various Forms of Policy Instruments and Climate Action

States and cities have adopted a range of climate actions and policies.

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32.22: Potential Emissions Reductions by Action, for the Year 2050

The size and cost of emissions reductions depend on available technologies and the source of related emissions.

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32.23: US Company-Level Mitigation Actions

A majority of US companies have made mitigation commitments, inventoried emissions, or participated in initiatives, but fewer are taking action.

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Focus on Compound Events

F1.1: Compound Events

Compound events have amplifying impacts on ecosystems and human communities and affect their capacity to respond.

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Focus on Western Wildfires

F2.1: Wildfire Impacts

Climate change has increased the area burned and severity of wildfires and impacts on the environment, human health, and society.

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Focus on COVID-19 and Climate Change

F3.1: Climate Change and Pandemic Risks

Climate change exacerbates infectious disease risk and increases health disparities.

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Focus on Risks to Supply Chains

F4.1: Climate Change and Food Supply

Climate change poses challenges to the animal food products supply chain.

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Focus on Blue Carbon

F5.1: Blue Carbon Ecosystem Sequestration Potential

Coastal blue carbon ecosystems play an important role in carbon sequestration but are vulnerable to climate change.

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Appendix 1: Assessment Development Process

A1.1: Authors of NCA5

Hundreds of experts from all across the US came together to develop NCA5.

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A1.2: NCA5 Zero Order Draft Public Engagement Workshops

Early public engagement helped inform the scope of NCA5.

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Appendix 2: Information Quality

Appendix 3: Scenarios and Datasets

A3.1: Downscaling Global Climate Model Data for NCA5

Global model data were downscaled and weighted to generate higher-resolution climate projections.

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Appendix 4: Indicators

A4.1: Changes in Temperature at Multiple Scales

Presenting indicators at different scales allows stakeholders to obtain information relevant to their needs.

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A4.2: USGCRP Indicators Platform

The USGCRP Indicators Platform leverages agency-supported science and data to understand how environmental, health, and societal conditions are changing.

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A4.3: Annual Greenhouse Gas Index

The warming effects of greenhouse gases are increasing over time.

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A4.4: Urban Heat Island (UHI) Intensity

Urban heat island intensity is increasing in many US cities due to the combination of urbanization and rising temperatures.

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A4.5: Billion-Dollar Disasters

The number of weather- and climate-related disasters exceeding $1 billion has substantially increased since 1980.

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A4.6: Changes in Arctic Sea Ice

Arctic sea ice is shrinking as the melt season grows longer.

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A4.7: Snowpack Changes in the West

Western snowpack is declining, peak snowpack is occurring earlier, and the snowpack season is shortening in length.

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A4.8: Flood Frequency and Magnitude West of the Mississippi River

Trends in flood magnitude and frequency vary widely across the western US.

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A4.9: Change in Drought Conditions

Long-term records show conditions are becoming drier in many portions of the West and wetter elsewhere, particularly the East.

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A4.10: Sea Level and Coastal Flooding in the Northeast

The combination of rising sea levels and the increased frequency of coastal flooding events exacerbates risk for coastal communities.

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A4.11: Marine Heatwaves

Extreme ocean temperatures are more common as ocean temperatures rise.

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A4.12: Marine Species Distribution

Marine species along US coasts are generally shifting northward to cooler waters.

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A4.13: Changes in Seasonality

Observed evidence of changes in seasonality reflect a warming climate.

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A4.14: Wildfires and Wildland–Urban Interface (WUI) Growth

Area burned by wildfires is increasing and the wildland–urban interface is expanding in the contiguous US.

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A4.15: Rangeland Production

Rangeland vegetation production has severely declined in some areas and increased in others.

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A4.16: Infectious Diseases Impacted by Climate Change

Climate, environmental, and social factors influence infectious disease rates.

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A4.17: Energy Production by Source

US energy production from renewables is increasing.

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Likelihood

Virtually Certain	Very Likely	Likely	As Likely as Not	Unlikely	Very Unikely	Exceptionally Unlikely
99%–100%	90%–100%	66%–100%	33%–66%	0%–33%	0%–10%	0%–1%

Confidence Level

Very High	High	Medium	Low
Strong evidence (established theory, multiple sources, well-documented and accepted methods, etc.) High consensus	Moderate evidence (several sources, some consistency, methods vary and/or documentation limited, etc.) Medium consensus	Suggestive evidence (a few sources, limited consistency, methods emerging, etc.) Competing schools of thought	Inconclusive evidence (limited sources, extrapolations, inconsistent findings, poor documentation and/or methods not tested, etc.) Disagreement or lack of opinions among experts

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