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The National Climate Assessment sits somewhere between a scientific triumph and a political punching bag. Required by law, written by hundreds of experts, and reviewed by the nation’s top scientists, it’s America’s definitive word on how climate change affects the country.
The report that MIT describes as the nation’s climate “State of the Union” gets produced every four years like clockwork. It tells Americans which regions face the worst flooding, how farmers should adapt to new growing seasons, and what military leaders need to know about climate risks to national security.
The problem? Politics get in the way of the science.
The latest drama unfolded in April 2025 when a single cancelled contract effectively killed work on the next assessment. Two dozen staff lost their funding. Volunteer authors got “released” from their roles. The entire legally-mandated program ground to a halt.
The National Climate Assessment represents something bigger: whether America can produce and use scientific information to make better decisions about its future. The battle over this report reveals deep tensions about the role of science in government and who gets to control the narrative about climate change.
How America’s Climate Report Gets Made
The National Climate Assessment didn’t emerge from thin air. It has deep roots in bipartisan legislation that passed with overwhelming support.
The Law Behind the Report
The Global Change Research Act of 1990 created the legal foundation for America’s climate science efforts. The Senate passed it unanimously, 100-0. Republicans and Democrats agreed the country needed coordinated research on global environmental change.
The law established the U.S. Global Change Research Program and gave it a clear job: produce a National Climate Assessment “not less frequently than every four years.” The assessment must analyze climate effects on everything from agriculture and energy to human health and national security. It must also project major trends for the next 25 to 100 years.
This isn’t optional. When the George W. Bush administration tried to skip an assessment, environmental groups sued. A federal court ruled in Center for Biological Diversity v. Brennan that producing the report is a legal duty, not a political choice.
Who Writes It
The assessment comes from a massive collaboration across the federal government. Fifteen agencies contribute, including NASA, NOAA, the EPA, the Defense Department, and the Agriculture Department. The whole effort gets coordinated through the White House Office of Science and Technology Policy.
The actual writing involves hundreds of experts. The Fourth Assessment had over 300 authors. The Fifth had over 500 authors and 260 technical contributors. These people come from every state and several U.S. territories. They include federal and state government officials, university researchers, private sector leaders, and nonprofit specialists.
NOAA often serves as the administrative lead, with its Climate Program Office’s Assessments Program organizing the massive undertaking. Other agencies both contribute to and use the final product. The Defense Department, for example, relies on the assessment for planning everything from base resilience to operational energy needs.
This structure creates both strength and vulnerability. The law mandates the assessment, making it legally durable. But the program that coordinates it has no direct budget authority over its member agencies. Funding flows through individual agencies, creating a critical weak point: an administration can cripple the assessment by targeting funding at just one agency.
The Review Process
The assessment’s credibility depends on a rigorous review process. The report doesn’t conduct original research. Instead, it synthesizes existing knowledge from thousands of peer-reviewed studies and technical sources.
Every draft goes through multiple rounds of scrutiny:
Federal Agency Review: Experts from all 15 member agencies check the draft for scientific accuracy and relevance to their missions.
Public Review: The draft gets released for public comment. Thousands of comments typically come in from citizens, organizations, and outside experts.
External Peer Review: Most importantly, an independent committee from the National Academies of Sciences, Engineering, and Medicine reviews the draft. This provides crucial validation from one of the nation’s most prestigious scientific bodies.
The process aims to meet high federal standards like the Information Quality Act and the Foundations for Evidence-Based Policymaking Act. The assessment’s strength comes from building on the collective work of the scientific community. But this same approach opens it to criticism about whether authors might select studies with positive or striking results over those with null or inconclusive findings.
From Static Report to Living Resource
The National Climate Assessment has transformed dramatically since its first edition in 2000. What started as a traditional text-based report has evolved into an interactive suite of resources designed to reach far beyond the scientific community.
Five Reports, Five Eras
Each assessment built on previous work while introducing key innovations:
First Assessment (2000): Called “Climate Change Impacts on the United States,” this pioneering effort organized around 20 regional studies involving dozens of experts. It created the first detailed portrait of potential climate effects across the country.
Second Assessment (2009): “Global Climate Change Impacts in the United States” expanded beyond identifying consequences to explicitly seeking adaptation measures and research priorities. This came after a significant gap during the Bush years.
Third Assessment (2014): This marked a major leap in accessibility. The report introduced robust regional chapters and an interactive online format for the first time. It emphasized decision-making frameworks for both adaptation and mitigation. The lead finding that climate change “has moved firmly into the present” resonated widely.
Fourth Assessment (2017/2018): Released in two volumes during the Trump administration, this assessment sharpened focus on economic consequences and emerging risks. Volume I stated with “extremely likely” confidence that human activities are the dominant cause of observed warming since the mid-20th century. Volume II quantified growing economic losses and highlighted risks like cascading failures across interconnected systems.
Fifth Assessment (2023): The most recent report continued the trajectory toward greater relevance and accessibility while introducing groundbreaking features to connect with broader audiences and address pressing societal concerns.
| Assessment | Year | Key Innovation | Main Focus | Political Context |
|---|---|---|---|---|
| NCA1 | 2000 | First comprehensive U.S. assessment; 20 regional studies | Potential consequences of climate change | End of Clinton administration |
| NCA2 | 2009 | Added focus on adaptation measures and research priorities | Impacts and adaptation needs | Early Obama administration |
| NCA3 | 2014 | Interactive online format; decision-making frameworks | Climate change “has moved firmly into the present” | Second Obama term with White House promotion |
| NCA4 | 2017/18 | Two-volume structure; quantified economic losses | Human activities are “dominant cause” of warming | Trump administration; Vol. II released on Black Friday |
| NCA5 | 2023 | Economics and Social Justice chapters; Art x Climate gallery | Disproportionate impacts and ongoing actions | Biden administration linking to federal investments |
Breaking New Ground in 2023
The Fifth Assessment marked the most ambitious effort yet to make climate science relevant and accessible. Responding to public input, it introduced several key innovations.
For the first time, dedicated chapters addressed Economics and Social Systems and Justice. These sections examined climate impacts on the U.S. economy, markets, and budgets, while acknowledging that climate risks disproportionately harm historically disadvantaged communities.
The report also included five “focus features” exploring emerging issues that don’t fit neatly into traditional categories. These covered compound extreme events, the connection between climate and western wildfires, the interplay of COVID-19 and climate change, supply chain risks, and the role of “blue carbon” in coastal ecosystems.
To reach beyond traditional scientific audiences, the assessment embraced new communication methods. It featured an Art x Climate gallery showcasing 92 artists from across the country, an opening poem by U.S. Poet Laureate Ada Limón, a companion podcast series, and a Spanish translation of the U.S. Caribbean chapter.
Making Data Work for Communities
A critical part of the assessment’s evolution involves transforming a massive report into usable tools. The premier example is the NCA Atlas, an interactive online platform that lets anyone explore climate projections for their community with data scaled down to the county level.
This tool empowers local decision-making by making abstract national trends tangible and locally relevant. A city manager in Phoenix can see specific projections for extreme heat. A farmer in Iowa can access tailored information about changing precipitation patterns.
Behind the scenes, other technologies support report creation. The NCA Sandbox helps hundreds of authors create clear, compelling data visualizations and figures essential for communicating complex findings.
These tools connect to a broader ecosystem of federal resources, including NOAA’s Climate Resilience Toolkit and the EPA’s Climate Change Indicators platform. Together, they work to translate cutting-edge science into actionable information.
The increasing detail creates new challenges. As the assessment provides more specific regional and local information, the task of synthesizing diverse findings into coherent national messages becomes more complex. This tension between unified national narrative and specific local data drives the push for a “sustained assessment” model that could offer more continuous, tailored products rather than a single report every four years.
Political Battles and Scientific Integrity
Despite its bipartisan origins and rigorous scientific process, the National Climate Assessment has become a political target. Its findings on climate causes and consequences have placed it in the crosshairs of administrations seeking to downplay climate risks.
A History of Interference
Political pressure on the assessment isn’t new, but it has escalated in intensity and changed character over time.
During the George W. Bush administration (2001-2009), interference often involved shaping or suppressing the scientific message. Tactics included systematic editing of government documents and websites to minimize the certainty and severity of climate science findings, delaying and suppressing reports, and restricting federal scientists from speaking freely with the media about their research.
The long delay in producing the second assessment during this period ultimately led to the lawsuit that compelled its release.
During the Donald J. Trump administration (2017-2021 and 2025-), tactics evolved from influencing the message to actively dismantling the process. Early actions included attempting to “bury” the Fourth Assessment by releasing it on Black Friday in 2018, a day of high consumer activity and low media attention.
The administration also installed political appointees with histories of climate change denial in senior positions at key agencies like NOAA, reportedly to undermine the assessment process from within. The call for authors for the Fifth Assessment was delayed for months, impeding its production schedule.
The most drastic actions occurred in 2025, when the administration took the entire globalchange.gov website offline, removing public access to all past and present National Climate Assessments. Scientists described this as “censoring science” and “serious tampering with the facts,” effectively painting over the windshield of a car heading into a dangerous curve.
The Funding Chokehold
The assessment’s operational fragility became clear in April 2025 with the cancellation of a NASA contract with consulting firm ICF International. This seemingly minor administrative action had devastating consequences.
ICF provided essential logistical and coordination support for the U.S. Global Change Research Program, acting as the operational backbone for the entire multi-agency assessment process. The contract cancellation effectively halted all work on the Sixth National Climate Assessment, legally due by 2028.
Two dozen staff at the program lost their funding. Shortly afterward, all non-governmental volunteer authors were “released” from their roles, with notice that the report was “currently being re-evaluated.”
This episode demonstrates the assessment’s funding vulnerability. Because the program doesn’t have its own budget and instead relies on contributions from member agencies, the entire legally mandated program can be paralyzed by a targeted budget cut within just one agency.
Even with a strong legal mandate, the assessment’s ability to function remains vulnerable to executive branch political priorities. An administration can defund the process without ever needing to amend the law that requires it.
Critiques from Multiple Directions
Beyond direct political attacks, the assessment faces substantive critiques regarding its methodology, framing, and communication. These arguments come not only from those who deny the underlying science but also from analysts who believe the assessment could be more objective and useful.
One line of criticism, from groups like the Heartland Institute, dismisses the assessment as a “purely political report” designed to generate alarm. These critics allege the report relies on flawed computer models and overemphasis on extreme, worst-case emissions scenarios to produce “blatantly absurd conclusions” and “hysterical” predictions of economic harm not supported by observational data.
More nuanced critiques come from organizations like the Breakthrough Institute, which argue that the assessment’s current form makes it less useful and more political than necessary. Their analysis moves the debate beyond simple denial into sophisticated discussion of methodology.
| Critique Category | Specific Criticism | Source | Proposed Reform |
|---|---|---|---|
| Framing & Bias | Focuses almost exclusively on negative impacts, ignoring potential opportunities | Breakthrough Institute | Evaluate full spectrum of impacts, both positive and negative |
| Methodology | Relies on subjective author judgment in selecting literature and prone to publication bias | Breakthrough Institute | Implement formal, transparent systematic review methods like PRISMA |
| Risk Assessment | Focuses narrowly on “additional climate risk” without context of other factors | Breakthrough Institute | Adopt “total risk” framework integrating climate impacts with technological, economic, and social changes |
| Scientific Basis | Based on flawed computer models and overreliance on extreme scenarios | Heartland Institute | Use full range of scenarios and transparently discuss model uncertainties |
| Communication | “Key Messages” written as persuasive “calls to action” rather than neutral findings | Breakthrough Institute | Present objective, data-centric summaries similar to meteorological reports |
The emergence of these more sophisticated arguments shifts the conversation from “Is climate change real?” to “Is this the most objective and useful way to assess it?” This creates a potential pathway for bipartisan reforms that could strengthen the assessment’s scientific foundation and broaden its political resilience.
Building a Better Climate Report
Facing political headwinds and evolving scientific needs, a robust conversation is underway about how to create a more resilient, relevant, and useful future for the National Climate Assessment. Four interconnected visions have emerged, each aimed at strengthening the assessment process and enhancing its value to the nation.
The Sustained Assessment Model
A primary vision transforms the assessment from static, quadrennial reports into a continuous, living process. This “sustained assessment” concept aims to provide more flexible and ongoing access to climate knowledge for decision-makers.
Instead of waiting four years for comprehensive updates, this model would allow continuous synthesis of new data, more frequent and targeted products, and dynamic feedback between scientists and the communities that use their information.
The goal is to better embed climate science directly into existing policies, plans, operations, and budgets. It would create a more responsive national climate information system capable of addressing the evolving needs of a broadening audience for climate projections and analysis.
Integrating Social Sciences
There’s growing consensus that for the assessment to be truly effective, it must move beyond its historical focus on physical science to achieve deeper partnerships with social sciences. Understanding the drivers, impacts, and potential responses to climate change requires integration of disciplines like economics, sociology, psychology, and political science.
The inclusion of dedicated chapters on Economics and Social Systems and Justice in the Fifth Assessment was a significant step in this direction. Future recommendations to deepen this integration include:
Diversifying Author Teams: Actively recruiting more social scientists, particularly for leadership roles like chapter leads, to ensure their perspectives shape the framing and analysis of the report.
Reconsidering Report Framing: Moving toward problem-based or solutions-oriented framing that naturally accommodates social science questions about governance, behavior, and equity, rather than trying to fit them into a purely physical risk-based model.
Filling Research Gaps: Directing federal research funding toward social scientific analyses of climate change to build the evidence base needed for future assessments.
Making the Process More Systematic
This vision directly addresses substantive critiques by proposing specific methodological reforms to bolster objectivity, transparency, and utility. The goal is creating a report perceived as less of a political document and more of an indispensable scientific resource by all sides.
Key proposals include:
Systematic Reviews: Adopting formal, transparent guidelines for literature assessment, such as the PRISMA framework, to minimize author bias and create clear, replicable processes for selecting evidence.
Balanced Framing: Systematically evaluating both threats and potential opportunities presented by a changing climate, providing a more complete and even-handed picture.
Contextualized Risk: Shifting from narrow focus on “additional climate risk” to a “total risk” framework. This would place climate impacts in broader context of other crucial factors like technological innovation, economic growth, and social change.
Objective Communication: Replacing persuasive, headline-style “Key Messages” with neutral, data-centric summaries that provide quantitative and comparative information needed for rigorous policy analysis.
Supporting Real-World Action
The purpose of a stronger, more integrated, and more systematic assessment is providing a credible scientific foundation for concrete mitigation and adaptation strategies across the nation. A robust assessment serves as the starting point for a vast range of actions that build resilience and reduce emissions.
The assessment already informs action at multiple levels:
Federal Level: Its findings are used in the Department of Defense’s climate adaptation planning, the Department of Transportation’s infrastructure investment decisions, and the overarching National Climate Resilience Framework.
State and Local Level: Regional chapters often serve as the first resource for local practitioners and inform state and city climate action plans, such as those in Pittsburgh and Phoenix, and improve municipal disaster preparedness.
Sector-Specific Action: The assessment provides scientific basis for promoting climate-smart agriculture, implementing nature-based solutions like wetland restoration, and planning the transition to a net-zero energy system.
The evolution toward a sustained assessment that provides actionable, localized data is part of a broader global movement toward developing “climate services”. These services aim to translate raw climate data and complex scientific projections into tailored, decision-ready information for end-users like farmers, water managers, public health officials, and infrastructure planners.
The National Climate Assessment is, in effect, the flagship U.S. contribution to this critical field. Its future stability and scientific integrity are linked to the nation’s ability to provide its citizens, industries, and governments with essential climate intelligence needed to navigate the challenges and opportunities of the 21st century.
What’s at Stake
The fate of the National Climate Assessment reflects broader questions about the relationship between science and democracy in America. Can a polarized political system support the kind of long-term, evidence-based planning that complex challenges like climate change require?
The assessment’s legal mandate provides some protection, but as recent events show, determined political opposition can find ways around legal requirements. The program’s dependence on funding from multiple agencies creates vulnerabilities that can be exploited without changing any laws.
At the same time, the growing sophistication of critiques from multiple directions suggests opportunities for reform that could strengthen the assessment’s scientific foundation and broaden its political support. Moving toward more systematic methods, balanced framing, and integrated social science could make the report more useful and less partisan.
The stakes extend beyond climate science. The National Climate Assessment represents a test case for whether American institutions can produce and act on scientific information about long-term challenges. Its success or failure will influence how the country approaches everything from pandemic preparedness to technological innovation to economic competitiveness.
For now, the future remains uncertain. The legal requirement for the assessment persists, but the practical ability to produce it hangs in the balance. Whether America can maintain this crucial source of climate intelligence may determine how well the country navigates the decades ahead.
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