Carbon dioxide
The image below shows the daily and hourly average carbon dioxide (CO₂) concentrations for the week ending May 4, 2026, recorded by the Keeling Curve, maintained by Scripps Institution of Oceanography at Mauna Loa Observatory. The latest CO₂ concentration was 433.50 parts per million (ppm).
The above image shows that the daily CO₂ concentration was 433.95 ppm on May 1, 2026 (yellow circle on the right) the highest daily reading on record. The image shows hourly (red circles) and daily (yellow circles) averaged CO₂ values from Mauna Loa, Hawaii, over 31 days. Note the recent wide range, with several hourly CO₂ reading exceeding 440 ppm.
The image below, dated May 5, 2026, shows daily (green circles), weekly (red lines) and monthly (blue lines) averages for the last year. The weekly average for the week beginning on April 26, 2026, was 432.44 ppm (red line top right). The monthly average for April 2026 was 431.12 ppm (blue line right). NOAA's CO₂ average daily concentration was at a record high of 433.95 ppm, at Mauna Loa, Hawaii, on May 1, 2026 (green circle right).
Highest CO₂ in millions of years, fastest rise, most solar radiation since Earth formed
To find CO₂ levels this high back in history, one needs to go back millions of years, as illustrated by the two images below, from an earlier post.
What makes current conditions even more dire is that not only are concentrations of CO₂ extremely high (without match going back millions of years) and rising, but the speed at which CO₂ is currently rising is also unprecedented, while additionally there has been an increase in total solar irradiance of ∼400 Wm⁻² since the formation of the Earth. The image below shows the combined climate forcing by changing CO₂ and solar output for the past 450 million years.
Between 14 and 15 million years ago, the temperature in central Europe was 20°C higher than today, as illustrated by the image below (adapted from a 2020 study by Methner et al.).
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| [ from earlier post, click on images to enlarge ] |
Concentrations of carbon dioxide haven't been this high for millions of years, as confirmed by recent analysis led by Sarah Shackleton and Julia Marks-Peterson. Their analysis finds that, while the average temperature of the ocean has decreased by 2 to 2.5°C over the past 3 million years, average atmospheric carbon dioxide levels have likely remained below 300 parts per million over this time. Methane levels have also remained relatively stable. This makes the recent daily concentration of 433.95 ppm at Mauna Loa and the high recent methane levels (see earlier post) even more threatening and it means that, in addition to the key role of heat-trapping greenhouse gases, there were important contributions from other components of the climate system such as Earth’s reflectivity, variations in vegetation and/or ice cover and ocean circulation.
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| [ from earlier post, discussed on facebook ] |
Greenhouse gas concentrations are rising and carbon dioxide and nitrous oxide are rising fast, while methane is rising even faster (see image on the right) and more methane threatens to erupt from the seafloor, as discussed in earlier posts such as this one and this one.
There are many feedbacks that further contribute to the temperature rise (such as albedo loss and more heat moving remaining in the atmosphere instead of being absorbed by oceans, ice and land, as discussed below). Altogether, this could result in a temperature rise of more than 20°C within one year, as discussed in an earlier post.
Sulfur hexafluoride
The image below shows a worrying recent rise in concentrations of sulfur hexafluoride (SF6), which has a global warming potential (GWP) over 100 years of 24,300 and, because it has a lifetime of 1000 years, its GWP over 500 years is even higher, i.e. 29,000 (IPCC AR6).
Regarding SF6, one does not have to bother to check historical levels, since the vast majority of SF6 in the atmosphere is a synthetic, industrial gas produced by people that leaked from its use mainly as an insulator in high-voltage and medium-voltage power systems and lines that can carry power over long distances. Clearly, too little is done politically to reduce SF6 emissions, even though there are safe, viable alternatives available to using SF6 in the power industry. Furthermore, rooftop solar systems can - where needed - be part of microgrids, which can reduce the need for transmission lines, poles and towers, which can also reduce fire hazards. Fire can also destroy warehouses where SF6 is stored in tanks.
The image below shows SF6 recorded at Ochsenkopf, Germany. The fact that Germany has strict regulations to prevent SF6 releases raises concerns that the high recent readings at Mauna Loa and Ochsenkopf may be the start of a global accelerated rise.
As temperatures rise, the outgoing longwave radiation (in black) has not risen as fast as the absorbed incoming solar radiation (in orange), due to high (and rising) concentrations of greenhouse gases and loss of albedo, resulting in an increasingly larger amount of extra energy stored on Earth. The image below, from an earlier post, depicts Earth energy imbalance (in red).
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| [ image by Leon Simons, discussed on facebook ] |
- Oceans
The ocean's capacity to act as an energy buffer is increasingly compromised by stratification, changes to ocean currents, changes in salinity, ocean oxygen depletion, acidification and more, as discussed in earlier posts such as this one. This is a big issue, since oceans take up 91% of the extra heat caused by greenhouse gases, so if there is even a 1% reduction in the heat taken up by oceans, the heat remaining in the atmosphere may double.
- Ice
Furthermore, the capacity for ice to act as a buffer by consuming energy in the process of melting is increasingly compromised by sea ice decline, by retreat of glaciers, and by darkening of ice due to dust, algae, black carbon and more. Arctic sea ice is facing a Blue Ocean Event with sea ice decline threatening to both dramatically lower albedo and reduce the ability for ocean heat to be consumed in the process of melting. Mountain glaciers are also in decline and permafrost is approaching the point where thawing of permafrost will speed up rapidly, as discussed in earlier posts such as this one.
- Land
The capacity for land to take up heat also faces a tipping point: The Land Evaporation Tipping Point can get crossed locally when water is no longer available locally for further evapotranspiration, i.e. from all processes by which water moves from the land surface to the atmosphere via evaporation and transpiration, including transpiration from vegetation, evaporation from the soil surface, from the capillary fringe of the groundwater table, and from water bodies on land. Once this tipping point gets crossed, the land and atmosphere will heat up strongly, due to the extra heat, i.e. heat that was previously consumed by evaporation and thawing, as described at this page.
- Atmosphere
As said, while the extra energy is increasing, as depicted by the above images, the capacity of oceans, land and ice to take up more energy is decreasing. Consequently, an increasingly large amount of extra heat threatens to accumulate in the lower atmosphere, especially in the Northern Hemisphere over land and in the Arctic, where temperatures are rising faster than anywhere in the world.
Conclusion
The situation is dire and unacceptably dangerous, and the precautionary principle necessitates rapid, comprehensive and effective action to reduce the damage and to improve the outlook, where needed in combination with a Climate Emergency Declaration, as described in posts such as in this 2022 post and this 2025 post, and as discussed in the Climate Plan group.
Links
• Keeling Curve - by Scripps Institution of Oceanography at UC San Diego
https://keelingcurve.ucsd.edu
• NOAA - Global Monitoring Laboratory - Carbon Cycle Greenhouse Gases - Mauna Loa, Hawaii
https://gml.noaa.gov/ccgg/trends/mlo.html
• IPCC AR6, Workgroup 1, Chapter 7, Supplementary material - SF6 GWP and lifetime
The situation is dire and unacceptably dangerous, and the precautionary principle necessitates rapid, comprehensive and effective action to reduce the damage and to improve the outlook, where needed in combination with a Climate Emergency Declaration, as described in posts such as in this 2022 post and this 2025 post, and as discussed in the Climate Plan group.
Links
• Keeling Curve - by Scripps Institution of Oceanography at UC San Diego
https://keelingcurve.ucsd.edu
• NOAA - Global Monitoring Laboratory - Carbon Cycle Greenhouse Gases - Mauna Loa, Hawaii
https://gml.noaa.gov/ccgg/trends/mlo.html
• IPCC AR6, Workgroup 1, Chapter 7, Supplementary material - SF6 GWP and lifetime
https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter07_SM.pdf
• Transforming Society
https://arctic-news.blogspot.com/2022/10/transforming-society.html
• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html
• Climate Emergency Declaration
https://arctic-news.blogspot.com/p/climate-emergency-declaration.html
• Transforming Society
https://arctic-news.blogspot.com/2022/10/transforming-society.html
• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html
• Climate Emergency Declaration
https://arctic-news.blogspot.com/p/climate-emergency-declaration.html
