New Weekly CO2 Concentration Record Set at the Mauna Loa Observatory, 431.73 ppm
As I've indicated repeatedly in my DU writings, somewhat obsessively I keep spreadsheets of the of the daily, weekly, monthly and annual data at the Mauna Loa Carbon Dioxide Observatory, which I use to do calculations to record the dying of our atmosphere, a triumph of fear, dogma and ignorance that did not have to be, but nonetheless is, a fact.
Facts matter.
When writing these depressing repeating posts about new records being set, reminiscent, over the years, to the ticking of a clock at a deathwatch, I often repeat some of the language from a previous post on this awful series, as I am doing here with some modifications now. It saves time.
The most recent post (not my last on this topic, assuming I live through this year) reflecting updating this last year is here:
New Weekly CO2 Concentration Record Set at the Mauna Loa Observatory, 430.86 ppm
The readings are, as of this morning as follows:
Week beginning on March 29, 2026: 431.73 ppm
Weekly value from 1 year ago: 427.26 ppm
Weekly value from 10 years ago: 405.65 ppm
Last updated: April 05, 2026
Weekly average CO2 at Mauna Loa
This is the new all time highest record, 431.73 superseding , 430.93 ppm record, set last week.
Most of the time I produce posts in this series, I refer to increases of the 1 year week to week comparators, generally when one of the readings among the 2,617 week to week comparators recorded at the observatory appears in the top fifty. For this week, week 18 of 2025, the increase over week 18 of 2024, the increase is 3.96 ppm higher, which places it as the 15th highest out of these 2617 points of annual week to week comparators going back to the mid 1970's.
The current reading is the 9th reading to exceed 430 ppm, seven of which happened last year, out of 2617 week to week comparators going back to the opening of the observatory in the second half of the 1970s.
It is one of only 38 readings to exceed an increase of 4.00 ppm, the first to place in the current year. Four of these readings exceed increases of 5.00 ppm, three of which were in 2024. Of the top 50 week to week/year to year comparators 27 have taken place in the last 5 years of which 13 occurred in 2024, 3 in 2025, 38 in the last 10 years, and 46 in this century.
Of the four readings from the 20th century, three occurred in 1998, when huge stretches of the Malaysian and Indonesian rainforests caught fire when slash and burn fires went out of control. These fires were set deliberately, designed to add palm oil plantations to satisfy the demand for "renewable" biodiesel for German cars and trucks as part of their "renewable energy portfolio." This case represents just one of the many cases demonstrating the unacceptable profile of so called “renewable energy” with respect to land use. The only other reading from the 20th century to appear in the top 50 occurred in the week beginning August 21, 1988, which was 3.91 ppm higher than the same week of the previous year. For about ten years, until July of 1998, it was the highest reading ever recorded. It is now the 47th highest.
As I always remark in this series of posts, if one looks, one can see that the rate of accumulation recorded at the Mauna Loa CO2 Observatory is a sine wave superimposed on a roughly quadratic axis:
Monthly Average Mauna Loa CO2
We should expect the final "all time record" in late April or in May, whereupon the concentrations will decrease until late September or October.
Weekly average CO2 at Mauna Loa
In 2025, the then highest value ever recorded 430.83 ppm took place in the week beginning May 5, 2025, and fell thereafter. In 2024, the then highest value ever recorded 427.94 ppm took place in the week beginning April 21, 2024, and fell thereafter. In 2023, the then highest value ever recorded 424.64 ppm took place in the week beginning May 28, 2023, and fell thereafter. In 2022, the then highest value ever recorded 421.63 ppm took place in the week beginning May 29, 2022, and fell thereafter and so on.
If we focus on the week to week comparators over a ten year period the situation is even more dire.
An interesting and disturbing thing about this week's reading is where it stands among comparators with the reading of ten years previous. Of all such ten year comparators among the 2161 comparators week to week comparator over a ten year period, this is tied for the 64th highest ever recorded. The highest, 27.65 ppm occurred in 2024, in the week beginning February 4, 2024, week 5, which also gave the highest single year comparator, that with week 5 of 2014.
The increase over week 13 of 2017 is 26.08 ppm.
All but one of the top 50 ten year week to week comparators have taken place since 2024. The one that didn’t occurred in 2021.
As it happens - I consider it statistical noise - 2026 has started out as a rather mild year for new accumulations of the dangerous fossil fuel waste carbon dioxide in the planetary atmosphere, when viewed as week to week comparisons with the same week of 2025. Only two weeks in 2026 have seen an increase over 3.00 ppm over that of 2025, that of week 8, the week beginning February 22, 2026, when the increase over week 8 of 2025 was 3.04 ppm, and this week. Overall however, the 21st century is appalling on this metric. In the 20th century, going back to 1976, 3.82% of weekly readings recorded and compared to the previous year exceeded 3.00 ppm. In the 21st century, 16.87% of weekly readings recorded and compared to the previous year exceeded 3.00 ppm.
One may wish to argue that the mild readings at the outset of 2026, the current reading notwithstanding, is all about solar and wind crap - all of which will be landfill in 20 to 25 years along with the batteries, with battery and hydrogen redundancy schemes designed to obscure that so called "renewable energy" is actually backed up by dangerous fossil fuels - that it is not, irrespective of my sense to the contrary - statistical noise.
People love to jump up and down celebrating the useless solar and wind industries despite their odious failure to address the collapse of the planetary atmosphere. I hear lots and lots of prattling about solar and wind in China - ignoring the huge tragedy of rather dirty lanthanide mines in Baotou - while no success is attributed to the fact that China has built 61 new nuclear reactors in this century, and has 38 under construction, a rate of nuclear construction not seen since the construction of more than 100 reactors in the United States, and over 50 in France in the 20th century.
Actually, though, my belief that nuclear energy is the only sustainable form of climate gas free energy that is acceptable and sustainable notwithstanding, I don't really believe the noble nuclear efforts of China are having much effect. It's helpful, but hardly enough. In a sustainable world, we would need thousands of nuclear reactors, not hundreds.
Assuming that the Mauna Loa CO2 Observatory is not shut by the anti-science bigots who have seized control of our government and canceled our Constitution, we are likely to see higher readings this year. The consequences, irrespective of whether the numbers are available and honestly reported, will not be subject to lies or misrepresentations by potentially thuggish liars; the planet will continue to burn, the weather will become more extreme and out of control. Oh and assholes will still carry on about how nuclear energy is "too dangerous," and the destruction of the planetary atmosphere is not "too dangerous."
These people will tell us, in a delusional counterfactual statement that so called "renewable energy" will save us. These chanting people who chant that "renewable energy" will save us and that nuclear energy is "too dangerous," will continue to so chant despite the observable fact that "renewable energy" has not saved us, isn't saving us, and, I assert, won't save us. People say we "need" solar and wind. We don't. They remain trivial sources of primary energy, their much hyped, in mathematically illiterate “percent” talk cannot keep pace with the growth in the use of dangerous fossil fuels. They have not and cannot stop dangerous fossil fuel wars, nor can they arrest the rising death toll from air pollution associated with dangerous fossil fuels.
The reactionary impulse to make our energy supplies dependent on the weather, this precisely at the time we have destabilized the weather by lying to ourselves about our continuous and rising use of dangerous fossil fuels, was always an ignorant attack on nuclear energy. It was never about preventing the extreme global heating we now observe, never about the environment (you don't tear the shit out of wilderness to make industrial parks and declare yourself "green" ) and never about costs, since the required redundancy - while kept off the books dishonestly - is expensive, and, as it is almost always fossil fuel based, dirty.
It is interesting and notable that the same people who still carry on with stupid reference to putative "costs" of nuclear energy that they themselves caused with picayune objections - they couldn't give a fuck about the cost of the extreme global heating we are now experiencing - and attack nuclear energy on this basis are completely and totally disinterested in attacking the unimaginable external costs of dangerous fossil fuels, costs recorded in millions of deaths and expensively treated diseases each year, the destruction of vast ecosystems by fire and alternately inundation or just plain heat.
Irrespective of their inane anti-science rhetoric about batteries and hydrogen, as it disregards the laws of thermodynamics, an apologetic orgy of wishful thinking designed to make the failed solar and wind industries appear to be reliable, which they will never be, all the money spent on solar and wind is clearly wasted and ineffective. The impulse is reactionary, to make our energy supplies depend on the weather, precisely at the time we have destabilized the weather because the reactionary fantasy is not working.
How much money is it?
The amount of money spent on so called "renewable energy" since 2015 is 4.9 trillion dollars, compared to 524 billion dollars spent on nuclear energy (including a vague term the IEA calls "other clean energy" ), much of the latter to prevent the willful and deadly destruction of existing nuclear infrastructure. Presumably "other clean energy" includes fusion, which has provided zero useable energy for any purpose
IEA overview, Energy Investments.
The graphic is interactive at the link; one can calculate overall expenditures on what the IEA dubiously calls "clean energy," ignoring the fact that the expenditure on so called "renewable energy" is basically a front for maintaining the growing use of fossil fuels. One may also download a *.csv file with the data.
My strong opinion that nuclear energy is the last best hope of the planet is not subject to change by appeals to clap trap about so called "nuclear waste," the big bogeymen at Fukushima, Chernobyl (and even more silly) Three Mile Island, blah, blah, blah...
I suggest finding someone more credulous than I to whom to chant endlessly about these points. Take a drive in your swell car out to a "no nukes" concert and convincing yourself that rock stars know more about energy than engineers and scientists. You deserve it. Whether future generations suffer in extreme poverty because of your smug pleasures and appalling selective attention is not your concern.
Oh, and of course, be sure self identify as an "environmentalist." As one who gives a shit about extreme global heating, I won't credit this self identification anymore than I credit Donold Trump's descriptions of himself as a "very stable genius" and all that, but who cares what I think? The "...but her emails..." and "...sane washed Donold Trump..." media describes antinukes as "environmentalists" after all, even if I find that absurd and delusional, so there's that.
Be sure to prattle on about your complete and total indifference to the laws of thermodynamics, laws of physics that are not subject to repeal by appeals to wishful thinking, by carrying on about energy storage, lots of battery bullshit, hydrogen bullshit, etc. as if there was enough so called “renewable energy” to store for months at a time. There hasn’t been any such "renewable energy" surfeits, to justify this junk, there aren't any and there won’t be any, but none of this should prevent you from the ruined landscapes and mining pits you leave for future generations. Screw future generations. If they need resources, they can sort through our landfills and ruins.
Tell everyone you know that it’s OK to spend ten times more money on solar and wind as we spend on nuclear energy, even though the trillion dollar quantities squandered on them haven’t done a damned thing to address extreme global heating, aren’t doing a damned thing to address extreme global heating, and won’t do anything to address extreme global heating, but will leave a legacy of dead industrial parks where wilderness used to be.
Do all these things. Don't worry. Be happy.
Our media will declare you an “environmentalist.” Good for you.
As for me, I'm far more concerned with the collapse of the planetary atmosphere than I am with the fear that someone somewhere at sometime may die from an industrial accident involving radiation. Let me repeat: I am far more concerned with the vast death toll, extreme environmental destruction, and the global heating associated with the normal use of dangerous fossil fuels than I am about carrying on insipidly about Fukushima.
Nuclear energy is not risk free, nor will it ever be. It is simply vastly superior to all other options, which in a rational world, as opposed to the one in which we live, would be enough to embrace it.
When our country, as precious as it has been to us, is an ancient memory, the rot we left behind in the planetary atmosphere will still persist.
History, should history remain recorded and accessible, will not forgive us, nor should it.
Have a pleasant Easter afternoon if you celebrate Easter for either religious or social reasons.