Carbon dioxide · updated 29 October 2026
CO₂ levels today: atmospheric carbon dioxide, live
Daily average at Mauna Loa, 29 October 2026. That is 53% above the pre-industrial level of about 280 ppm, and 1.70 ppm higher than the same month last year.
The Keeling curve: CO₂ at Mauna Loa (ppm)
How fast is CO₂ rising? Annual increase (ppm per year)
What it means, according to scientists
CO₂ concentrations are now higher than at any time in at least 2 million years, according to the IPCC. The increase since 1750 is caused by human activities — mainly burning coal, oil and gas, and deforestation.
CO₂ is long-lived: a large share of what we emit today stays in the atmosphere for centuries. That is why the IPCC finds global warming is roughly proportional to cumulative emissions, and why temperatures only stop rising once net CO₂ emissions reach zero.
The rate of increase is also speeding up: in the 1960s CO₂ rose by under 1 ppm per year; in the last decade it has averaged over 2 ppm per year.
Sources: IPCC AR6 WG1 Summary for Policymakers (A.2.1, D.1.1);NOAA Global Monitoring Laboratory.
Frequently asked questions
What is the CO₂ level today?
The latest daily reading at Mauna Loa Observatory, Hawaii, was 427.20 ppm on 29 October 2026. The monthly average for 2026-09 was 426.07 ppm (NOAA).
What was the CO₂ level before the industrial revolution?
About 280 ppm. Today's level is roughly 53% higher. Ice cores show CO₂ stayed between about 180 and 300 ppm for at least the last 800,000 years.
Why does CO₂ go up and down during the year?
Plants in the Northern Hemisphere absorb CO₂ as they grow in spring and summer and release it in autumn and winter. That creates a yearly cycle, peaking around May and bottoming out around September, on top of the long-term rise.
Why is CO₂ measured at Mauna Loa?
The observatory sits at 3,400 m on a remote Pacific volcano, far from local pollution, so it measures well-mixed air. Its record, started by Charles David Keeling in 1958, is the longest continuous direct CO₂ record. Readings at other stations worldwide show the same trend.
What is a safe level of CO₂?
There is no single official threshold. What matters for warming is the total amount of CO₂ emitted: the IPCC finds that warming is roughly proportional to cumulative emissions, and stops rising only when net CO₂ emissions reach zero.
Source:NOAA Global Monitoring Laboratory, Mauna Loa Observatory
Licence: Public domain (US Government work). Cite: Lan, X., Tans, P. and K.W. Thoning, NOAA/GML.
Latest data: 29 October 2026 · Checked: 31 October 2026 ·Download CSV · Methodology