The Inevitable 2014 Headline: ‘Global CO2 Level Reaches 400 PPM For First Time In Human Existence.’


By Peter Gleick, via Science Blogs

Sometime, about one year from now, the front pages of whatever decent newspapers are left will carry a headline like the one above, announcing that for the first time in human existence (or in nearly a million years, or 3 million years, or 15 million years), the global atmospheric concentration of carbon dioxide — the principal gas causing climate change — will have passed 400 parts per million (ppm).

That’s a significant and shocking figure. Unfortunately, it’s only a temporary marker on the way to even higher and higher levels. Here are the most recent (March 2013) data from the Mauna Loa observatory showing the inexorable increase in atmospheric CO2 and the rapid approach to 400 ppm.

There is a range of estimates around the detailed time record of atmospheric composition, and the study of changes in atmospheric carbon dioxide concentrations over the billions of years of the Earth’s existence is an exciting area for research. A commonly cited figure with strong evidence comes from measurements of air trapped in ancient ice cores obtained from Antarctic ice. We now have a detailed 800,000 year record, which shows clearly that atmospheric CO2 levels never approached 400 ppm during this period.

In December 2009, a research team from UCLA published a paper in Science that suggested we would have to go back at least 15 million years to find carbon dioxide levels approaching today’s levels. This research used isotopic analysis of shells in deep sea sediments, and reported that CO2 concentrations may not have exceeded 400 parts per million since the Mid-Miocene Climatic Optimum (MMCO) — between 16 and 14 million years ago. The MMCO was associated with reduced planetary ice volumes, global sea levels 25 to 40 meters higher than today, and warmer ocean temperatures. Decreasing CO2 concentrations after that were associated with substantial global cooling, glaciations, and dropping sea levels.

Gavin Schmidt of NASA’s GISS has pointed me to research in a December 2011 article in the journal Paleoceanography by Gretta Bartoli, Bärbel Hönisch, and Richard E. Zeebe, reporting on paleoclimatic records that suggest CO2 concentrations (at least in the Northern Hemisphere) may have been around 400 ppm between 2 and 4.6 million years ago. This evidence comes from isotopes measured in planktic foraminifer shells spanning 2.0 to 4.6 million years ago and indicates that atmospheric CO2 estimates during the Pliocene gradually declined from just above 400 ppm to around 300 ppm in the early Pleistocene 2 million years ago.

800,000 years ago? Three million years ago? 15 million years ago? More research will continue to clarify the variability of Earth’s atmospheric composition over time, as well as the impacts for the planet as a whole of screwing with it. (That’s a technical term…)

But the more important point to remember is that never in the history of the planet have humans altered the atmosphere as radically as we are doing so now. And the climatic consequences for us are likely to be radical as well, on a time-scale far faster than humans have ever experienced.

– Dr. Peter Gleick is a climatologist. This post originally appeared on Science Blogs and is reprinted here with permission.

Related Posts:

34 Responses to The Inevitable 2014 Headline: ‘Global CO2 Level Reaches 400 PPM For First Time In Human Existence.’

  1. Mike Roddy says:

    Good one, Peter, thanks.

    Predictions: One in five newspapers will report 400 ppm on the front page. One in five readers will understand what that number implies. The rest will know far more about Kim Kardashian’s baby shower and Honey Boo-boo’s new hair style.

    The media is not just complicit in downplaying the most important story in history, they are proactive, and answer to advertisers and right wing ownership. Climate activists go to the media as supplicants, hoping their latest protest or story will be covered. As a result, they are brushed off as “climate people”.

    This is what has to change, or nothing else will.

  2. David Goldstein says:

    Peter: I am wondering why you didn’t mention the possibility of hitting 400 this May. Last May was 396.78. Recently, the year-over-year rises have often been over 3 ppm. Feb 2013 was 3.3 higher than Feb 2012. In the larger scheme of things it is no big deal- we’ll hit 500, 600, etc. before we know it at the rate we are going – but, for a numbers nerd such as myself it is interesting to note that THIS could the 400 year. Also- perhaps a statistician could analyze the seeming ‘jack-up’ of the recent CO2 rises…have we had a shift to 2.5-.3.5 annual rise rate?

  3. Robert in New Orleans says:

    I am of the opinion that this threshold will be crossed this year.

  4. Sasparilla says:

    Robert you could very well be right as the trends are there to support your opinion.

    Year over year from 2012 February (393.54ppm) to 2013 February (396.80ppm) which is 3.26ppm increase from 2012 to 2013 so far.

    The high last year in May was 396.78, add 3.26ppm (the gain from 2012 so far in February) to that and you get 400.04ppm.

  5. Sasparilla says:

    Excellent article Peter…something we can expect to see (as Robert points out above) this year or next year for sure.

    I like the technical term and we need to stop doing that technical term with the atmosphere.

  6. Sasparilla says:

    I should point out that the gain between 2011 / 2012 in February was significantly smaller than the end gain between 2011 / 2012 May – so there is the, not unreasonable, possibility we might not just break into a 400ppm number, but go to 401ppm or higher (hopefully not jeez..).

  7. I think it’s possible. We have three months left of seasonally increasing CO2 values and February showed 396.8 ppm CO2, 3.6 ppm higher than last year.

  8. Correction… 3.26 ppm higher. But, yes, I agree it’s possible we hit 400 ppm this year. Not a happy prospect.

  9. wili says:

    Yes. The latest weekly number is 397.30, with two recent daily numbers coming in at (above) 398 and (nearly) 399!

    So, any day now, we could have the first Mauna Loa reading above 400. Other locations have already passed this threshold, particularly in the north.

    If there was going to be evidence that we were starting to move in the right direction (or at least not as fast in the _wrong_ direction), it would be that CO2 concentrations were increasing in smaller and smaller increments. This might suggest that we were approaching the day when the increase would be nothing, and then the decrease would begin.

    This is not what is happening.

    We are going ever faster in the wrong direction.

    What we who understand the problem have been doing to stop this train wreck has not been working.

    One good definition of insanity is doing the same thing over and over and expecting a different result. ]

    So, what should we be doing differently?

    Or is the destructive juggernaut impossible to even lessen the rate we are accelerating toward our doom?

  10. David Goldstein says:

    ‘so, what should we be doing differently?’…obviously the $64 question. As all CP posters know already, climate change mitigation runs into 2 enormous and (possibly) intractable obstacles: 1) The additive, rampaging, exponential, devouring nature of growth capitalism. 2) The human propensity to react and respond only when there is a perception of visceral right here/right now ‘there is a tiger in my cave’ sense of threat and danger. Yes, according to CO2 trends, we are going in the exact wrong direction. So…my answer to your question:
    1) Grieve the likely consequences of our folly and limitations 2) Get as creative and powerful with your actions around climate change as you can and see if you can stay a bit joyful while doing it (a ‘Zorba the Greek’ attitude) . Yep, grieving and joyful at the same time- quite a path climate activists have to walk. (fwiw- I am producing a 5 minute video of a grandparent apologizing to his grandchild for the world we may be leaving them- along with an exhortation for climate activism at the end. Look for it on social media near you in the near future).

  11. Jack Burton says:

    Mauna Loa provides an ideal location to get a measurement of CO2, this is indicated by the nice clean oscillations we see in the seasonal CO2 concentrations.
    One of my most favorite climate change arguments occurred a few years back on our town’s local website discussion board. The deniers are everywhere and they make up over half of all comments here when this topic gets aired out on the boards. So in the midst of a heated debate, it was announced by one of our more right wing deniers that all us liberals who are stupid enough to believe the Mauna Loa readings are just simply too stupid to be taken seriously. Why you ask? Well, according to this luminary of scientific knowledge, “Everyone knows that Hawaii is home to some naval, marine corps and air force air bases. It is common knowledge that their planes exercise in the air space around the islands. Thus Mauna Loa is presenting false readings, as we all know CO2 is a product of jet fuel burning in these planes. This proves just how stupid the liberal mind is.”
    All rather funny, if he was not typical of many right wing FOX brainwashed fools who vote and lobby hard to prevent any and all action on CO2 emissions. In this world of political foolishness, people actively vote and lobby for their own destruction.
    Image the mind it takes to actively seek the ruin of this world for themselves, their kids and grand kids. Point this out to them and they become enraged. I seriously think they would resort to violence in order to keep CO2 on the rise and to make sure we blow past 2 degrees on the way to 11 degrees. Literally fighting to destroy themselves. It takes a better man than me to fathom the mind at work behind the denier community. They simply defy human intelligence.

  12. M Tucker says:

    “I agree with Gleick that crossing the 400ppm mark will be significant. I also tend to agree with others who have posted here that it is likely to happen this year. The significance is alarming. At no time in Earth’s past has CO2 increased so rapidly and this time humans are doing it. This time it is not naturally produced CO2 as it was during the Miocene or the Pliocene. As the recent study published in Science clearly shows this rapid anthropogenic carbon dioxide is producing unprecedented AGW at a rate never before seen in Earth history.

    I find is a bit surprising that Dr Gleick had not heard of the Pliocene warm period before. That is a well researched period in Earth history and the climate reconstructions have been used for years to test climate models. Dr Gleick ought to contact the USGS. They are the repository for this research and the ongoing climate reconstructions are called the PRISM (Pliocene Research Interpretation and Synoptic Mapping) project.

    I am also aware of the Mid-Miocene warm period but I find it hard to believe that period has been as well researched with as many testing sites as the Pliocene warm period. Both suggest CO2 concentrations in the range of 400ppm but, due to the proxy used, they carry wide uncertainties. It may be that CO2 concentrations where slightly less than 400ppm which I think is extremely troubling. Both climate reconstructions suggest warming in the range of 2 to 3 degrees C warmer than today with sea level in the range of 25 meters higher. Yeah, 25 meters! That is why I cannot take seriously anyone who says we can limit warming to 2C with CO2 in the 450ppm range. I am much more persuaded by paleoclimate reconstructions then by climate models.

    As for the 400ppm mark…It will just be another signpost we will race past without deceleration or pause on our way to the climate cliff.”

  13. SecularAnimist says:

    wili, your comment implies that advocates of urgent action against global warming are doing the same things today that they have been doing for 25 years or so.

    It doesn’t look like that to me at all. On the contrary, it looks like advocacy and activism has exploded in just the last few years, and people are doing plenty of things now that have not been done before.

    Likewise, implementation of at least some of the key technologies needed to eliminate GHG emissions has dramatically accelerated in recent years.

  14. Solar Jim says:

    Earth (i.e. natural law) is responding to total radiative forcing of all hothouse gases, not carbonic acid gas alone. This is discussed sometimes in terms of CO2equivalent, which will pass 500 ppm in a few years. Some reduction in forcing occurs today due to temporary pollution aerosols, which will be present only for as long as we emit them on a daily basis.

  15. catman306 says:

    I wonder what if the odds makers in Las Vegas are wagering on this event? Maybe if they were, it would appear as ‘news of the day’ in the main stream media.

    Get out the word!

  16. TreeBanker says:

    @Mike Roddy,

    You’re right on the money Mike.

    It’s sad that we live in a society that values entertainment above all else.

    Storms that knock out power to millions of televisions is the thing that makes most people scream the loudest.

  17. BobbyL says:

    I think one problem is that the world has been changing much faster than any efforts to reduce emissions. When this issue first really became public in the 1980s the US was by far the biggest carbon dioxide polluter and over on the other side of the world a country with more than 1 billion people named China was first beginning to experiment with capitalism. While many Americans were zipping around highways in German luxury vehicles in the 80s most Chinese were still getting around on bicycles. Fast forward about 30 years and the change is mind blowing. China is now by far the biggest carbon dioxide polluter, doubling US emissions and they have several hundred million people living in the middle class. They also are the kings of coal accounting for 47% of all coal burning and have plans to ramp up coal burning even more. Naturally their next door neighbor India, which also has more than 1 billion people, was impressed and has embarked on a pretty similar journey toward becoming a rich modern country itself and they also burn a lot of coal. So as we put up solar panels and wind turbines and shut down coal-burning plants and even reduce our emissions from the peak in 2005 we shouldn’t be shocked that carbon dioxide emissions globally keep soaring. Frankly, I don’t think anyone has a clue about how to reduce global emissions.

  18. Sasparilla says:

    It could be even worse than it appears David.

    The rise for February 2013 from last February (as you know is 3.24ppm) – the difference in the change the previous year from Feb 2011 – Feb 2012 was 1.72 ppm, but the difference from the high in May 2011 to May 2012 was 2.57ppm (so that was almost a full 1ppm difference added by May).

    Follow the trends from last year and we would be looking at a gain of 4.1ppm or so this year.

  19. steve says:

    If you want your kids to grow up with the same opportunities you had, the time for solving climate change is now.

  20. David Goldstein says:

    Right on, Bobby. If and when the U.S. ever gets around to declaring climate change to be the emergency that it is and begins to take comensarate actions- that is only the bare beginning. China and India (and other developing countries ) are an entirely, entirely, entirely different situation. If it were only the ‘old guard’ developed countries- maybe, just maybe a draw down of emissions would be possible. But…

  21. Alexander Williamson says:

    Greetings; Unfortunately, in the ‘States, mostly the only news that commands public attention is ” ‘tainment”, unless a) there is a sudden war, or b) Americans are killed.

    Otherwise, Australasia, Africa, and South and Southeastern Asia might as well not exist, for all that they are even mentioned.

    Sad, but true.

  22. Dennis Tomlinson says:

    “…a ‘Zorba the Greek’ attitude”.
    David, this news makes me feel more like there’s a ‘Fiddler on the Roof’, and the Cossacks have taken notice of us.

  23. Brian R Smith says:

    One thing we could do differently is spend, say, $179 million on the whole defeat denialism/ establish science credibility/ educate, engage the public/ pressure Obama problem. $179M is 1% of the total income ($17.8B) of environmental non-profits in 2012.

    How to spend that war chest would be the charge of a war room of cross-sectoral experts who design & implement campaigns in accord with overall strategy.

    35 million is the estimate of climate-issue voters in the U.S.

    War Room + War Chest + 35M voters = course correction for climate politics.

  24. Daniel Coffey says:

    Why is 400 any more important than any other number for CO2 concentration? I know, we are supposed to consider it a threshold, but for what? Math? Even numbers divisible by 100? So what?

    The energy accumulation due to massively increased greenhouse gas concentrations have already passed the point of no return, so 400 ppm is just a slightly higher accumulation rate on top of a level which already dooms civilization, wildlife, the Amazon, etc.

    I have become less and less impressed by the thinking of the whole of environmental leaders and organizations, as their behavior on the ground is feckless, very ordinary and predictable, typically focused on protests and divestiture. None of these behaviors will have any effect on what is already in the atmosphere and no one seems willing to do what is needed to get levels down: build the alternative energy systems needed to displace oil, coal and natural gas.

    Really, for quite some time the focus has been on trivial distractions instead of facing up to the consequences of what is already in the “global warming” pipeline. The notion that adding more greenhouse gases will change the outcome overlooks the basic reality that we already have way too much of such materials in the atmosphere for the glaciers, ice sheets and oceans to absorb and buffer against. The only thing higher concentrations achieve is a higher rate of accumulation, not a neutral level of accumulation.

    Somehow people continue to overlook that in order to achieve a higher balance or equilibrium temperature for re-emitting energy in order to achieve a new – 2 or 4 or 6 C temperature equilibrium, much of the thermal buffer of the planet will continue to be consumed. The cold spots will continue to absorb energy, ice will continue to melt, etc.

    Anyway, all of the sensible solutions have been blocked by environmentalists, oil, coal, and natural gas interests. None seems willing to do what is needed, as it inconveniences them all. A failure to understand the nature of the challenge has created this paradox.

  25. BobbyL says:

    I think 400 makes a difference psychologically. For example, in baseball, winning 20 games is a really big deal whereas winning 19 isn’t, also hitting .300 is something special whereas hitting .299 seems to be much less of an accomplishment. In climate change anything above 450 has become a really scary number so any number with a 4 in front is scarier than numbers starting with 3. Finally reaching 400 should add some urgency. It may translate into some votes in Congress. The countdown to 450 will be next. That’s big.

  26. Mulga Mumblebrain says:

    When you add up the facts, ie the scientific consensus of ‘settled science’, the evidence from reality of climate derangement worse than the most pessimistic predictions, the kicking in of feed-backs and forcings (most notably the loss of Arctic summer sea ice)the total unwillingness of Western polities to act in the face of unprecedented danger, and the ever more fanatical opposition of the business bosses and the deranged droogs of the Rightwing lumpen death-seekers, I believe that you can only come to one conclusion. That the powerful wish catastrophe to occur, probably for some hideous Malthusian reason, to be rid of billions of unwanted people, and that the death impulse in the Rightwing mediocrity is even more powerful than the most pessimistic might have thought.

  27. Mulga Mumblebrain says:

    It is now a question of ‘..if you want your kids to grow up’, full bloody stop!

  28. Mulga Mumblebrain says:

    Zbigniew Brzezinski recommended ‘titietainment’, a mixture of titillation and entertainment, to keep the serfs obtunded, and he wasn’t half right, was he?

  29. Brian R Smith says:

    When you add up the facts, we are f’d, no question. But it’s early to claim the powerful desire catastrophe. The powerful are not stupid; power itself relies on a stable climate. Climate-disabled economy = no power. Self-destruction seems an unlikely motive. Occam’s razor suggests rather that unthinking, across the board ignorance and blind greed is informing an irrationality that unfortunately could kill everyone, krill & all. In this case, banishing ignorance by whatever means necessary is baseline for hope. And that is a problem worth solving.

  30. SecularAnimist says:

    Daniel Coffey wrote: “I know, we are supposed to consider it a threshold, but for what?”

    It’s just a nice round number, that’s all.

    Might as well complain about people partying extra hard on New Year’s Eve when the calendar rolled over to 2000.

  31. Sasparilla says:

    Obviously Rupert was listening…

    And you’re right Mulga he was more than half right. ;-)

  32. John Mason says:

    Aye Mike – this was what started me off writing for Skeptical Science. Hours doing whack-a-mole with deniers on comment-threads were swapped with reading papers and writing about them. I hope to hell I’m making a difference in my own small way.

  33. John Mason says:

    Oh well, Mulga – they’ll have to grow their own veg and muck out their own pig-stys at that point. I’m not taking the mickey out of your post of course – that will become their reality.

  34. Mulga Mumblebrain says:

    John, I’m sure that they plan to keep a few serfs alive to service their desires, plus they’ll need trustworthy armed forces etc. But the vast masses in Africa, south Asia, Latin America, even the burgeoning underclasses in the West-these they have always feared and hated, and we know that they have discussed what to do about this ‘problem’ in their elite cabals. I simply do not believe that the combination of utter greed and absolute stupidity can explain the still fanatic resistance to saving mankind. They could make pretty much as great sums in profit from renewables and new industries, yet they insist on keeping fossil fuels a-burning, and sequester tens of trillions, unspent, in tax haven bolt-holes.