What Was in the Last National Climate Assessment Report?

The National Climate Assessment (NCA) is the U.S. government’s official, comprehensive report on climate change impacts, risks, and responses across the United States.

It is a congressionally mandated report required under the Global Change Research Act of 1990, which calls for an assessment to be provided to the President and Congress at least every four years.

The most recent report, the Fifth National Climate Assessment, was published in 2023. You can find it here: https://nca5.climate.us/

The assessment is produced through the U.S. Global Change Research Program (USGCRP), an interagency program that coordinates climate and global-change research across 15 federal agencies. Nearly 100 NOAA scientists and staff contributed to the fifth climate assessment.

I decided to read through the most recent NCA report myself. Here are a few highlights that stood out to me.

The report begins by explaining that as the planet continues to warm because of human-caused greenhouse gas emissions, many types of extreme weather are becoming more frequent or severe:

"As the world’s climate has shifted toward warmer conditions, the frequency and intensity of extreme cold events have declined over much of the US, while the frequency, intensity, and duration of extreme heat have increased. Across all regions of the US, people are experiencing warming temperatures and longer-lasting heatwaves. Many other extremes, including heavy precipitation, drought, flooding, wildfire, and hurricanes, are becoming more frequent and/or severe, with a cascade of effects in every part of the country."

The impacts aren't limited to loss of life, health, and property. They also carry a significant economic cost for the country. The report states:

"In the 1980s, the country experienced, on average, one (inflation-adjusted) billion-dollar disaster every four months. Now, there is one every three weeks, on average. Between 2018 and 2022, the US experienced 89 billion-dollar events. Extreme events cost the US close to $150 billion each year—a conservative estimate that does not account for loss of life, healthcare-related costs, or damages to ecosystem services."

The report also discusses climate justice, which refers in part to the unequal distribution of climate risks and impacts. Some lower-income and historically marginalized communities face greater exposure and vulnerability to climate-related hazards, even though their contributions to greenhouse gas emissions may be relatively small.

The assessment explains:

"Fossil fuel–based energy systems have resulted in disproportionate public health burdens on communities of color and/or low-income communities. These same communities are also disproportionately harmed by climate change impacts."

This isn’t simply an opinion—the conclusions in the National Climate Assessment are based on decades of scientific research, observations, and data.

The report summarizes the broader picture this way:

"Global greenhouse gas emissions from human activities continue to increase, resulting in rapid warming and other large-scale changes, including rising sea levels, melting ice, ocean warming and acidification, changing rainfall patterns, and shifts in timing of seasonal events. Many of the climate conditions and impacts people are experiencing today are unprecedented for thousands of years."

Below is a chart that gives a good overview as to why human-activity is substantially responsible for global warming.

So what are the suggested solutions?

• Decarbonizing the electricity sector, primarily through expansion of wind and solar energy, supported by energy storage

• Transitioning to transportation and heating systems that use zero-carbon electricity or low-carbon fuels, such as hydrogen

• Improving energy efficiency in buildings, appliances, and light- and heavy-duty vehicles and other transportation modes

• Implementing urban planning and building design that reduces energy demands through more public transportation and active transportation and lower cooling demands for buildings

• Increasing the efficiency and sustainability of food production, distribution, and consumption

• Improving land management to decrease greenhouse gas emissions and increase carbon removal and storage, with options ranging from afforestation, reforestation, and restoring coastal ecosystems to industrial processes that directly capture and store carbon from the air

Below are also key points mentioned:

• To reach net-zero targets, the US will need to add new electricity-generating capacity, mostly wind and solar, faster than ever before. This infrastructure expansion may drastically increase demand for products (batteries, solar photovoltaics) and resources, such as metals and critical minerals. Near-term shortages in minerals and metals due to increased demand can be addressed by increased recycling, for example, which can also reduce dependence on imported materials.

• Nature-based solutions that restore degraded ecosystems and preserve or enhance carbon storage in natural systems like forests, oceans, and wetlands, as well as agricultural lands, are cost-effective mitigation strategies. For example, with conservation and restoration, marine and coastal ecosystems could capture and store enough atmospheric carbon each year to offset about 3% of global emissions.

Note that net-zero CO₂ emissions means that emissions are reduced to zero, or that any remaining emissions are balanced by removing an equivalent amount of CO₂ from the atmosphere.

In regards to jobs, the suggestion is to ensure fossil fuel-workers are trained and supported in their transition. Below is what the assessment says about this:

"A 'just transition' is the process of responding to climate change with transformative actions that address the root causes of climate vulnerability while ensuring equitable access to jobs; affordable, low-carbon energy; environmental benefits such as reduced air pollution; and quality of life for all. This involves reducing impacts to overburdened communities, increasing resources to underserved communities, and integrating diverse worldviews, cultures, experiences, and capacities into mitigation and adaptation actions. As the country shifts to low-carbon energy industries, a just transition would include job creation and training for displaced fossil fuel workers and addressing existing racial and gender disparities in energy workforces. For example, Colorado agencies are creating plans to guide the state’s transition away from coal, with a focus on economic diversification, job creation, and workforce training for former coal workers. The state’s plan also acknowledges a commitment to communities disproportionately impacted by coal power pollution."

Based on all of this information, the key takeaway for me is that it is absolutely possible for humanity to do a better job of caring for our planet. Yes, we are already experiencing the effects of climate change, including more extreme weather events associated with greenhouse gas emissions. But there are solutions, and I personally believe we should be listening to the climate scientists who have spent decades studying these issues and identifying ways forward.

What about the next climate assessment?

The sixth assessment is supposed to be completed by the end of 2027. In April 2025, the Trump administration informed nearly 400 scientists across the United States that they were being released from their roles in preparing the sixth National Climate Assessment.

Then, in June 2025, two important federal climate websites were taken offline.

Climate.gov: On June 24, 2025, NOAA took down Climate.gov, which had served as a major public source of climate education, data, and research for nearly 15 years. NOAA said the material was being consolidated into NOAA.gov and affiliated websites. Former members of the Climate.gov team have since created Climate.us, an independent, nonprofit-supported successor that aims to preserve much of the information that was previously available through the government site.

Globalchange.gov: On June 30, 2025, the website for the U.S. Global Change Research Program also went offline. The site had served as the federal gateway for the USGCRP and provided access to the National Climate Assessments and other climate information.

With these changes, it will be interesting to see what happens with the sixth National Climate Assessment and what it will look like when it is released.