For some reason, it has become hard to locate the various National Climate Assessments (NCAs) that have been produced by the USGCRP over the decades (and it’s pretty hard to find the USGRCP as well…). However, the reports are still accessible if you know where to look. So for future reference, here are all the links (and we’ve downloaded the pdfs locally so that they will always be available here).
NCA1 (2000)
- Full report (via the internet archive) (via gov archive) (local pdf)
NCA2 (2009)
- Full report (via the internet archive) (via gov archive) (local pdf)
NCA3 (2014)
- Full Report (via the NOAA library) (local pdf)
- Climate Science Supplement (via the internet archive) (local pdf)
NCA4 (2017)
- Volume 1 Climate Science Special Report (via the NOAA library) (local pdf)
- Volume 2 Impacts, Risks, and Adaptation in the United States (via the NOAA Library) (local pdf)
NCA5 (2023)
- The NCA5 Atlas (via ESRI)
- Full report (via the NOAA Library) (local pdf)
NCA6
There is no ongoing NCA6 process, even though it is mandated by Congress to be completed over the next few years. We’ll let you know if that changes.
Thank you for doing this. Don’t have any polite words for why it seems okay in D.C. to ignore that NCA6 remains still required by LAW. Guess Article I of the U.S. Constitution doesn’t seem to matter much these dark days, so I’ll just again say thank you for this.
Thank you! I was wondering if the reports had been archived somewhere accessible. Much appreciated.
Thank you for this. The destruction of history, or at least the attempt to destroy history, is the condition for an attack on democracy. It is good that these documents at least will not be lost to posterity.
Thank you, thank you, thank you!
I wish I saw this post earlier this week as I was looking for one of these reports and had to rely on the wayback machine. It’s crazy how important reports like this can apparently disappear so quickly.
Thank you! We need backups because there is great danger of erasure by the present regime.
Thank you very much. NCA6 will restart the latest in January 2027.
How are we going to deal with the loss of the Mauna Loa observatory? Are there other locations where CO2 is being flask-tested?
Barton Paul Levenson: – “How are we going to deal with the loss of the Mauna Loa observatory?”
As far as I’m aware there are at least two observatories on Mauna Loa measuring atmospherics:
1. Scripps Mauna Loa Observatory, measuring atmospheric CO2 concentrations since 1958.
https://scrippsco2.ucsd.edu/data/atmospheric_co2/primary_mlo_co2_record.html
2. NOAA Mauna Loa Observatory, measuring atmospheric CO2 concentrations since 1974.
https://gml.noaa.gov/ccgg/trends/
Other surface-based observatories are shown in the global map included in the YouTube animation at:
https://www.youtube.com/watch?v=8KrgPPO1h0A
“This is exactly what Joseph Stalin did.” – Michael Mann response in the Guardian story below
“Scientists decry Trump energy chief’s plan to ‘update’ climate reports: ‘Exactly what Stalin did’”
https://www.theguardian.com/us-news/2025/aug/07/climate-assessments-chris-wright-trump
And Mann is right. The Energy Department rewriting prior official reports mandated by law that have been “conducted under the auspices of the Global Change Research Act of 1990” and “through the U.S. Global Change Research Program (USGCRP), a collaboration of 13 Federal agencies and departments” is outwardly disgustingly dystopian. (Quotes courtesy of National Climate Assessment Wikipedia page)
But I suspect Wright can see what is going to happen after the EPA Endangerment Finding is scrapped. The doors to a blizzard of lawsuits against companies seeking compensation for climate change related damages will be opened, and he knows that the “DOE Critical Review of Impacts of GHG Emissions on the US Climate (Christy, Curry, Koonin, McKitrick, Spencer, 2025)” is a very slender solitary reed to hold up in future proceedings. And the administration can hardly indemnify companies on the one hand, while claiming greenhouse emissions are not a serious problem or constitute pollution under the Clean Air Act requiring government oversight. (Quote from https://www.realclimate.org/index.php/archives/2025/07/the-endangerment-of-the-endangerment-finding/ )
So now he will oversee the rewrite of previous National Climate Assessments (NCA’s) in order to muddy the legal waters and increase confusion in the public. I suspect that a certain trio of Special Government Employees will be involved, their work made easy since the rules that governed previous NCA’s no longer seem to matter.
Please pickup your phone and voice your objections to your congressman and both of your senators about this planned rewrite of past findings. Then write an email or letter. Then followup. For the sake of our children and grandchildren. This is America, but you’re going to have to fight to save it. Rewriting prior findings produced using vigorous scientific practices is about as unAmerican as it gets.
And thank you again Real Climate for making access to these previous five NCA’s available and safe from altercation.
Thanks for making these resources available. Much needed as we continue work to climate adap[tation and the health safety and welfare of the planet.