What Atmospheric CO2 Says About the Relative Health of the Earth's Economy Before the Iran War

Quite a lot has happened since the last time we looked at now the pace at which carbon dioxide is accumulating in the Earth’s air is changing.

The reporting of atmospheric CO₂ concentration data collected at the remote Mauna Loa Observatory has been delayed, not just because of the Senate Democrats’ government shutdown fiasco, but also because of staff changes at the National Oceanic and Atmospheric Administration. The latest data that the NOAA used to routinely publish on or shortly after the fifth of each month hasn’t been available on that schedule. At this writing, the CO₂ data is only available through February 2026.

That’s okay this time around because it lets us present a timely snapshot of what the trend for that data was before the geopolitical event of the Iran War took place. The Iran War didn’t begin until 28 February 2026, which means whatever disruptive impact it has had on oil and gas production, shipping, and consumption isn’t yet included in the dataset.

The following chart shows how the rate at which carbon dioxide has been changing in the Earth’s atmosphere from January 2000 through February 2026:

Atmospheric carbon dioxide concentration data lags behind changes in CO₂ output from human activities, taking several weeks to diffuse into the Earth’s air after being emitted. For example, the peak in January 2025 coincides with Chinese emissions peaking in December 2024, which itself coincides with efforts by China’s exporters to crank up production to beat the clock on new U.S. trade tariffs going into effect in 2025. January 2025 saw the Biden administration final tariff increases go into effect, while President Trump’s new tariffs were put into effect in April 2025. Not uncoincidentally, there’s a short spike upward in May 2025 that would correspond with a surge by producers in China to beat the clock on April 2025′s tariffs.

Since the atmosphere’s pace of CO₂ accumulation peaked at 3.57 ppm in January 2025, it has fallen by a full 1.00 ppm to 2.57 ppm through February 2026. With an estimated world population of 8.005 billion people, that drop represents roughly a reduction of 7.8 billion metric tonnes of carbon dioxide emissions. It also represents an estimated $33.23 trillion decline in the world’s GDP in the last 13 months.

China’s reduced output of carbon dioxide emissions, primarily stemming from its involuntarily reduced industrial output, represents a large share of that overall decline. If not for the impact of the global tariff war, it is highly unlikely a decline of this magnitude would have occurred in the absence of a major global recession.

Or perhaps a highly disruptive geopolitical event, like the Iran War, which has an outsized scope. Our next few snapshots will give a measure of just how disruptive the Iran War has been for the Earth’s economy.

References

National Oceanographic and Atmospheric Administration. Earth System Research Laboratory. Mauna Loa Observatory CO2 Data. [Online Data]. Data as of 5 March 2026.

Image Credit: CO2 Skywriting photo by Matthias Heyde on Unsplash.