Unpacking the Fifth National Climate Assessment

The Environmental and Energy Study Institute (EESI) held a briefing about the U.S. Global Change Research Program's fifth National Climate Assessment (NCA5). NCA5 is the most comprehensive, holistic, and inclusive report to date on national climate risk and response. Panelists discussed the report’s emphasis on the need for “rapid and deep” greenhouse gas emission reductions and the resulting economic and health benefits. The report also highlights the importance of investing in adaptation to the impacts of climate change—impacts which exacerbate existing climate and social injustices.

NCA5 draws from a wide breadth of scientific literature across the fields of energy, natural resources, air quality, agriculture, and other sectors to provide insights tailored to different regions and communities across the United States. Speakers discussed how members of Congress can use this report to understand the nuances of climate impacts and solutions in their districts and states, leveraging its takeaways to inform decision-making at the national level.

Highlights

KEY TAKEAWAYS

The findings from the Fifth National Climate Assessment (NCA5) help policymakers understand the causes and impacts of climate change as well as the available tools to build enduring resilience to hazards.
NCA5 is designed to be very accessible. Chapters are organized by sector of the economy, by mitigation and adaptation, and by geographic region. The data underpinning the report are also publicly available.
U.S. greenhouse gas emissions have been decreasing since 2007. At the same time, U.S. gross domestic product (GDP) and population have continued to increase.
More people across the United States are experiencing climate change right now than ever before. In the 1980s, the country experienced, on average, one $1 billion disaster (in 2023 dollars) every four months. Now, there is a $1 billion disaster, on average, every three weeks.
The NCA5 Atlas is an online digital tool designed for users to explore their own specific questions about climate change in the United States.

Rep. Scott Peters, U.S. Representative (D-Calif.)

National Climate Assessments have been informing policy makers for over 20 years.
The findings from the Fifth National Climate Assessment (NCA5) help policymakers understand the causes and impacts of climate change as well as the available tools to build enduring resilience to hazards.
As the United States works to combat the climate crisis, it is also critical to prepare communities for the unavoidable destruction of climate change.
The bipartisan and bicameral National Coordination on Adaptation and Resilience for Security Act (NCARS) (3261/H.R.6311) mandates the development of a national strategy to streamline climate adaptation work and the creation of a permanent position at the White House to coordinate U.S. climate resilience efforts.

Rosina Bierbaum, Westin Chair of Natural Economics, School of Public Policy, University of Maryland; Professor, School for Environment and Sustainability, University of Michigan

The Global Change Act of 1990 (L.101-606) requires a report to Congress and to the president that integrates, evaluates, and interprets the findings of the multi-agency U.S. Global Change Research Program. The report must discuss scientific uncertainties and analyze the effects of global change on the natural environment, agriculture, energy, land, water, transportation, human health and welfare, social systems, and biological diversity. It is also expected to model climate emissions and impacts 100 years into the future.
These reports, the National Climate Assessments, have been produced for both Republican and Democratic administrations. It is a significant multi-agency effort (15 federal agencies were involved in NCA5).
NCA5 is designed to be very accessible. Chapters are organized by sector of the economy, by mitigation and adaptation, and by geographic region. The data underpinning the report are also publicly available.
NCA5 is written for Congress, but the information included in the report can inform the work of a wide variety of people from health officers and floodplain managers to city planners and farmers.
This assessment includes new chapters on economics and social systems and justice. The report looks more closely at which communities are disproportionately impacted by climate change. The report finds that it is often the poorest people in any part of the country that are most impacted.
The report explores progress made on climate adaptation. Hundreds of cities and dozens of states have adaptation plans, but very few municipalities and states have substantial implementation underway and even fewer have taken steps to evaluate how well their practices worked and what more could be done.
Adaptation work is not keeping pace with climate impacts. In 2023, the United States experienced 28 weather and climate disasters that each caused losses of $1 billion or more.
Nature-based solutions, like storing carbon in forests, soils, and mangroves, deserve more attention because they can provide both mitigation and adaptation solutions. They are also popular across the political spectrum. A recent S. Nature4Climate poll found that 92% of U.S. voters support the deployment of nature-based solutions.

Allison Crimmins, Director, National Climate Assessment, U.S. Global Change Research Program; Office of Science & Technology Policy, Executive Office of the President

NCA5 is policy relevant, but not policy prescriptive. It does not provide recommendations on what policies to advance, rather it provides readers with the information needed to make decisions.
NCA5 was written by 500 authors and 250 technical contributors from every U.S. state, as well as the District of Columbia, Guam, Palau, Puerto Rico, and the U.S. Virgin Islands.
Some overall takeaways from the report are:
- Communities across the country are taking climate actions, particularly at the state and city levels, to reduce emissions and build resilience.
- U.S. greenhouse gas emissions have been decreasing since 2007. At the same time, U.S. gross domestic product (GDP) and population have continued to increase.
- More people across the United States are experiencing climate change right now than ever before. In the 1980s, the country experienced, on average, one $1 billion disaster (in 2023 dollars) every four months. Now, there is a $1 billion disaster, on average, every three weeks.
The new chapter on economics finds that climate change impacts and damages will impose substantial new costs on the U.S. economy and limit economic opportunities for many Americans.
The assessment highlights that some overburdened and underrepresented communities are at higher risk of climate impacts due to the cumulative effects of social and economic inequities caused by ongoing systemic discrimination, exclusion, and underinvestment.
Across the entire nation, Black communities are expected to experience a disproportionate share of future flood damages. Already, neighborhoods that are home to racial minorities and low-income families have the highest inland flood exposures in the South.
Widespread implementation of currently available and cost-effective technologies can advance the United States substantially towards the U.S. goal of net-zero greenhouse gas emissions by 2050. To reach the goal, the United States also needs to expand annual growth in wind and solar capacity faster than ever before.
There are near-term benefits that come from taking mitigation and adaptation actions. For example, clean energy industries create jobs.
There are many ways to explore NCA5, many of which are new to this assessment:
- Art × Climate is the NCA5 art gallery featuring 92 pieces of art.
- The assessment begins with the poem, STARTLEMENT, by Ada Limón, the 24th Poet Laureate of the United States.
- There is a NCA5 companion podcast, which includes a reading of the executive summary.
- The NCA5 Atlas is an online digital tool designed for users to explore their own specific questions about climate change in the United States. There are also downloadable figures throughout the report.
- In April 2024, the entire report will also be available in Spanish.

Adrienne Hollis, Vice President of Environmental Justice, Public Health, and Community Revitalization, National Wildlife Federation

Climate mitigation includes greenhouse gas emissions reduction and removing carbon from the atmosphere, with the goal to avoid or reduce the effects of climate change. It is the most cost-effective response to climate change.
Successful mitigation means reaching net-zero greenhouse gas emissions. Net zero means that the amount of greenhouse gases that are being removed from the atmosphere should equal the amount of greenhouse gases that are being emitted into the atmosphere.
A U.S. energy system with net-zero emissions would require widespread improvements in energy efficiency, substantial electricity generation from solar and wind energy, and widespread electrification of transportation and heating. These steps are economically feasible now.
Greenhouse gas emissions from the agriculture sector can be reduced through changes to agricultural practices and making the U.S. food system more efficient.
Some technologies that will be needed to reach net-zero emissions are not yet on the market. Areas in need of further research, development, and demonstration are carbon capture, utilization, and storage; long-duration energy storage; low-carbon fuels and feedstocks; next-generation electricity transmission; and carbon dioxide removal.
Substantial greenhouse gas emission reductions could improve human health, reduce pollution of land and water, and address legacies of inequity. For example, shutting down a coal-fired power plant reduces greenhouse gas emissions and improves local air quality.
Efforts are already underway to accelerate climate mitigation. Twenty-five states, 675 cities, 300 universities, and hundreds of companies have announced net-zero emission targets.

Caitlin Simpson, Climate Adaptation Partnerships Program Manager, National Oceanic and Atmospheric Administration (NOAA) Climate Program Office

Adaptation is the process of adjusting to an actual or expected environmental change and its effects in a way that seeks to moderate harm or take advantage of beneficial opportunities.
The adaptation chapter finds that climate adaptation activities are occurring in every region of the United States, but they are small in scale, incremental in approach, and lacking sufficient investment.
Adaptation activities must address the uneven distribution of climate harms and incorporate collaboration with local communities.
Financial, cultural, technological, legislative, and institutional changes are needed to address the shortcomings of adaptation actions.
Effective adaptation requires centering equity. For example, housing discrimination played a significant role in putting certain homes in hazardous areas, so now these communities need specific support to adapt.
Equity must be a visible part of the work. Actions that seem neutral to past inequities can reproduce inequitable outcomes.
Transformative adaptation is needed to adequately address climate risks. This involves persistent, novel, and significant changes to institutions, behaviors, values, and technology. Current adaptation practices in the United States are predominantly incremental and do not clearly add up to a system-wide transformation.
For example, expanding access to cooling centers and air conditioning during a heatwave is an important incremental adaptation action, meaning a small change to business as usual. In contrast, deploying a city-scale district cooling system so that indoor air temperatures do not reach dangerous levels is an example of a more transformative change.
There are several federal programs that provide decision support for climate adaptation, including NOAA’s Climate Adaptation Partnerships Program, the U.S. Department of Agriculture’s Climate Hubs, and the U.S. Geological Survey’s Climate Adaptation Science Centers.
Adaptation investments and financing are difficult to track and are likely inadequate. The report highlights that investing in adaptation now will reduce the costs later.

Louie Rivers, Senior Social Science Advisor, U.S. Environmental Protection Agency Office of Research and Development

“Patterns of climate risk, social vulnerability, and climate adaptation in the Southeast echo centuries of human history. The region consists of highly diverse communities and landscapes, including one of the most biodiverse areas in the continental United States. The Southeast’s ecosystems, stewarded for generations by Indigenous Peoples, are now in a precarious state. Centuries of political and land-use decisions have threatened the landscape and the people, with a few prospering at the expense of many. These decisions, shaped by a long history of systemic and structural racial discrimination and aggression, continue to have lasting harmful effects on the preparedness of Southeast communities for mounting climate change threats. The institutions of slavery and intergenerational ownership of individuals as property, Jim Crow segregation, and housing discrimination have resulted in many Black, Indigenous, and People of Color communities living in neighborhoods that are disproportionately exposed to environmental risks and with fewer resources to address them when compared to majority White communities.”

Introduction of NCA5 Chapter 22: Southeast

It is important to accurately talk about the past, as described in the first paragraph of the Southeast regional chapter, in order to generate solutions that will keep the United States moving forward and serving all communities.
Between 2010 and 2020, there was a lot of in-migration to coastal and urban areas in the Southeast. This influx of people stretched the capacity and resources of some of these communities. At the same time, people left rural areas. These areas are home to already disproportionately vulnerable populations and people leaving further reduced the capacity of those communities to respond to climate change.
Climate change disproportionately impacts jobs, households, and economic security in the Southeast. In particular, the chapter explores the intersection between intergenerational poverty and climate change.
In the Southeast, capacity varies significantly. For example, a rural community with low capacity hit by a hurricane might have to close their school for a month while they attempt to rebuild. In contrast, in a suburb of a major city with higher capacity that is impacted by that same hurricane, the schools would probably be able to re-open the day after the storm ends. This demonstrates how a climate impact can have cascading effects in low-capacity communities.
Agriculture in the Southeast faces growing threats, but innovations offer help. Southeast Black farmers face disproportionate weather and climate risk, especially drought.

Q&A

Q: How do the findings in NCA5 relate to items on the Congressional agenda?

Bierbaum

The Farm Bill has significant potential to advance conservation through the Conservation Stewardship Program and the Environmental Quality Incentives Program.
The funding from the Infrastructure Investment and Jobs Act (IIJA) (L. 117-58) and the Inflation Reduction Act (IRA) (P.L. 117-169) had moved the needle on supporting climate solutions; however, funding for ecosystem programs received far less support than mitigation.
Since 2017, 41 bills have been enacted that, if implemented effectively, encourage climate adaptation and resilience. More work can be done to coordinate the U.S. response to climate impacts as outlined by Rep. Scott Peters in the National Coordination on Adaptation and Resilience for Security Act. The White House has put out a National Climate Resilience Framework, which is moving in that direction.
Decision-makers should be thinking about adaptation and mitigation in just about any piece of legislation drafted.

Crimmins

Having the funding is one thing, but reaching widespread deployment of clean energy technologies is going to be tough.
NCA5 includes a lot of case studies, particularly in the regional chapters, that highlight the actions communities are taking on both mitigation and adaptation. These case studies are designed to help communities learn from each other.

Hollis

NCA5 can help focus attention on areas that have been lacking that attention from decision-makers, including communities affected first and worse by climate impacts.

Q: If a Congressional district is not in a position to prioritize greenhouse gas emission reductions, what do you recommend it prioritize?

Crimmins

One option is to focus on health. There are key messages on health in every single regional chapter in NCA5.

Hollis

There are a variety of reasons that a community may not be in a position to reduce greenhouse gas emissions. Some communities do not have significant sources of greenhouse gas emissions. Others may have emissions to address, but do not have the capacity or political will to take different actions. Depending on a community’s situation, one can think about different ways to frame the challenge.

Bierbaum

Another option is to focus on improving the livability of a community. This might raise issues like walkability and green space. Addressing these issues would give you the chance to improve health outcomes and reduce the urban heat island effect.
All communities need to think about reducing their vulnerability to extreme events, like floods and droughts.

Rivers

Communities can focus on building capacity. For example, training people to be grant writers to access funding to support other services in the community.

Q: What are examples of bipartisan solutions to climate change?

Crimmins

NCA5 highlights how expensive climate change is. Actions to reduce greenhouse gas emissions and adapt to climate change are much less expensive than experiencing climate change. Taking action will save communities and the federal government a lot of money.
Nature-based solutions are quite bipartisan. For example, creating parks with green space and trees generates many win-wins, including a place for recreation, better health outcomes, a social space for communities, improved water quality, a buffer against extreme weather events like flooding, and a carbon sink.

Bierbaum

The way the U.S. economic system currently works, the cost of damages from climate impacts are hard to add up, and, at the same time, the cost of the clean energy infrastructure is easy to add up.
There is work to be done to better quantify the benefits of avoiding the damages and of installing the clean energy infrastructure.

Q: Does NCA5 address the issue of waste?

Crimmins

The report touches on waste, but it is not a main focus.

Hollis

The mitigation chapter talks about food waste.

Q: How does NCA5 talk about agriculture? How would you like to see the agriculture sector change?

Hollis

The mitigation chapter talks about optimizing land use and improving agricultural practice.
Other sections of the report address air and water pollution from concentrated animal feeding operations.

Bierbaum

Some of the agricultural practices to think about are regenerative agriculture practices, no-till farming, multi-cropping, and agrivoltaics. Agrivoltaics is the practice of growing crops under solar panels.
The conservation programs of the Farm Bill help to reduce emissions and increase the resilience of the agriculture sector.

Rivers