Current CO2 concentration in the atmosphere


For about two weeks I’ve been pondering what to say about David Hilfiker’s blog post, Hope in an Environmental Wasteland.

Thanks to some personal matters that needed my attention, plus the amount of work needed to do a response justice, I had nearly thrown in the virtual towel. But then a conversation cropped up in the comments on a post I wrote the other day (A video postcard from Eaarth) that is at least tangentially applicable, which nudged me back in the direction of commenting on Hilfiker’s post plus those comments left here, all in one hopefully coherent blogtopian smorgasbord.

Before I dive in, let me stress that I agree with a lot of what Hilfiker says, such as the inherent difficulty of making large-scale changes that will significantly reduce America’s CO2 emissions. I do, however, disagree with him on some points, which provided the impetus for this post. Whatever you think of the snippets I quote here and what I have to say about them, I strongly recommend you read his entire, long post.

First, I want to call out two specific parts of Hilfiker’s post, conveniently in adjacent paragraphs, which I’ll then address individually.

Although the majority of Americans recognize the reality of climate change and want governmental action, there has been no sustained popular demand for a change in policy. Why not?

Most Americans are deeply committed to their material lifestyle. The unspoken reality is that any effective challenge to climate change will require a radical transformation of that material lifestyle. Environmentalists and their organizations generally want to avoid this “inconvenient truth,” but the energy for indoor temperatures to our satisfaction, transportation of food, importation of goods from distant lands, personal transportation, manufacturing and much else all guzzle fossil fuels and emit CO­2. A sustainable level carbon emissions—ie a level that the natural earth could recycle without rises in atmospheric CO­2 levels—would be about two tons of CO­2 for each person in the world per year. The average American uses 20 tons. As China, India and other poor countries develop economically, it’s utterly unrealistic—to say nothing of unjust—to expect them to keep to a 2-ton limit unless the Western world reduces its consumption accordingly.

What would 2 tons per year for the average American look like? It’s difficult to imagine, but for starters it would mean:

  • no air travel (period)
  • mostly local transportation on foot or bicycle (or the not-yet-existent) adequate public transportation
  • vegetarian, if not vegan, diets
  • only locally produced food … even in the winter
  • no air conditioners … even in the South
  • elimination of individual ownership of luxuries (and many other things we consider necessary), for instance, TVs, computers or washing machines
  • reducing the average size of our homes by at least a third, if not a half (or having others share our space)
  • and so on

If you’ve read this blog for any length of time, surely you’ve guessed that the first point I want to talk about is this two tons per capita number. As best I can tell, this approximation came from taking the current rate at which CO2 is absorbed by the biosphere and dividing it by the population. So all the CO2 sucked up by plants, the oceans, and other natural processes, pro-rated among the 7 billion+ human beings on the planet gives us about two tons per person. If we kept global emissions on that budget, the atmospheric level would, presumably (a distinctly loaded word), hover right around the current level, about 390 parts per million. That two-ton number sounds about right, and I won’t challenge it.

But here’s the nasty detail, and the one that struck me when I first read this: I’ve fairly well marinated myself in environmental material for the last decade, and somehow I had never seen anyone slice and dice the numbers exactly this way. And frankly, it’s a terrifying number. If you look at the CDIAC’s most recent figures for per capita CO2 emissions on a country basis (figures are for 2008, expressed in metric tons of carbon, not CO2, so you have to multiply them by 3.667 to get tons of CO2), you’ll see that two tons per capita per year of CO2, or 0.545 tons of carbon per capita per year, requires the whole world to fall somewhere between the current emissions of Guyana, at 125th place, and Ecuador, at 126th. The US and China are, to no one’s surprise, well beyond that limit, with the US clocking in at about 18 tons per capita per year, and India just barely under the magic number.[1][2]

Frankly, the longer you ponder the two tons metric, the tougher it is to make the case that we can hit that mark any time soon.

But the situation is much more complicated than that, obviously. One of life’s nasty little lessons, in my experience, is that the tougher a goal seems to be, the more important it is to question whether it’s the right goal. In other words, do we really want to try to stabilize the atmospheric CO2 at 390 ppm? Of course not. We are currently at that level and also in a state of thermal disequilibrium — the CO2 that’s already in the air is causing additional warming, so halting CO2 at 390 ppm would result in decades of continued climate change and therefore more droughts and floods and sea level rise and other knock-on effects. Plus, we’d be playing Russian roulette with the monsters under our collective bed, feedbacks. What is the magic point at which we start to unleash permafrost carbon and/or methane hydrates in climatically significant amounts? (i.e. Large methane emission upon spring thaw from natural wetlands in the northern permafrost region – Abstract – Environmental Research Letters) How much extra kick do we see when Arctic melting really gets under way? And remember that a large portion of the CO2 that’s taken up by the Earth’s natural systems is absorbed by the oceans, triggering acidification and its own symphony of horrors, clearly not something we want to keep pushing toward its own tipping points. So even the Herculean political, economic, engineering, and social tasks of stabilizing at 390 ppm would result in anything but a stable environment, and it might send us veering wildly into a state that makes Bill McKibben’s Eaarth look like a pleasant afternoon sitting next to a cool mountain lake.[3]

In short: Holding the line at or near 390 ppm of CO2 in our atmosphere is a virtual impossibility, given the latencies involved — meaning that timeline I mentioned in a comment on my earlier post:

The issue is how much of the not-quite-worst impacts we’ll lock in before we have that long-overdue epiphany. This is where the timing issues I’m always blathering on about become our worst enemies. Imagine a timeline that runs from “we wake up” through “we figure out what to do”, “we get the right governments in place to do it”, “we implement the right policies (taking into account the long drag caused by the need to make massive infrastructure changes)”, “CO2 emissions drop a lot”, and “atmospheric CO2 levels start to decline”, finally ending at “we overcome the thermal disequilibrium and see a reversal of warming”. That’s a pretty long timeline, and we’re still trying to figure out how to get to the first milestone (the epiphany).

The second sticking point I have with Hilfiker’s post is his description of what a two-ton lifestyle would mean for Americans. The overriding problem is the inherent assumption that we will do the things he mentions — flying, producing food, running air conditioners, etc. — with the same carbon footprint as we do in 2012. This is a dangerously naive assumption, and not one, speaking as an economist, I would consider betting on. No one should dare accuse me of being in love with the “magical ability of the marketplace” to pull an infinite number of rabbits out of its hat to save us from ourselves in the coming decades and centuries. But that doesn’t mean that I or anyone else should ignore that policies and technologies do change, and there are some potential synergies we can exploit, the biggest and perhaps most obvious one being that between electricity generation and the electrification of transportation.[4]

Does anyone think that on a warming world we will see Americans in the South willingly forgo all air conditioning? For those who haven’t been there, especially in some of the more humid areas, I think this is laughable. Hell, I can’t imagine anyone making it through a warmer than normal summer in the US North sans AC, and in really bad years, like 2012, it would be beyond miserable and therefore career suicide for any politician who tried to ban or severely limit the use of air conditioning.

You can pick your own, similar nits with some of the other items I quoted on his list.

So while I would argue that the idea of stabilizing atmospheric CO2 at 390ppm is wildly optimistic in terms of both it being “enough” and its feasibility, I would say that the potential impacts on American lifestyle are very pessimistic in the short run (we just won’t accept them unless absolutely forced) and optimistic in the long run (as the list assumes that we would take such drastic steps — I suspect that we still won’t, even once things start to hit the fan).

But back to the broader context, and a comment Lewis Cleverdon made in that prior post I linked to above and want to comment from extensively here, in part to give it a bit more exposure:

First, i wonder if you’d agree that we know some parts of what we’re locking into our future, including:
- around forty years of intensifying impacts (to 2052) from the timelagged warming off our past pollution output;
- another ~forty years of intensifying impacts after that (to 2092) if we take as much as forty years to end our net GHG emissions;
- ending our net GHG output also ends our maintenance of the cooling Sulphate Parasol, giving an additional warming of between 80% and 140% (says Hansen);
- CO2 then resides in the atmosphere for a prolonged period due to the outright loss of some carbon sinks and the swamping of others by the interactive carbon feedbacks, some of which are already active and accelerating.

Thus what we are already committed to, assuming that included zero emissions by 2052, does not permit a natural decline of airborne CO2e within a timescale to avoid the positive feedbacks taking over. We know of no negative feedbacks capable of preventing them from making the planet largely uninhabitable.

Second, one of the parts that we don’t know is how soon we’ll have put enough heat into the oceans to commit us – maybe far down the road – to the destabilization of the massive seabed methyl clathrates stocks – which would be beyond any geo-engineering’s control. Thus I wonder if you might agree that effective geo-engineering as an adjunct to emissions control is not simply an inevitable panic response ? That it is in fact the utterly necessary and urgent requirement to halt further warming of the oceans and the further acceleration of the feedbacks ?

For any who may question this on grounds that it doesn’t cleanse the atmosphere, and so doesn’t avoid terminal ocean acidification, I’d entirely agree that such cleansing is one essential form of geo-engineering – we have to be looking at Emissions Control AND Carbon Recovery AND Albedo Restoration – none of these is optional; all three are requisite to resolving our predicament.

Meanwhile, according to the recent slightly veiled statement by the UK’s Chief Scientist, we are within 15 or 20 years of serial global crop failures, and the giga-deaths and conflict they would entail. The nearer we get to that global destabilization, the more difficult the negotiation of the essential climate treaty to legislate the global strategy of “Contraction & Convergence for Recovery”.

Meanwhile, how many Americans yet see that current US climate policy is actually bipartisan ? That both Bush and Obama and Romney are quite content with the rising threat of climatic destabilization facing the Chinese Govt – If, or when, the Chinese people get hungry enough and overthrow it, that would be the end of China’s bid to usurp America’s global economic dominance.

So the third question is whether you can see any higher priority for American nationalism than the deflection of any real threat to US global economic dominance ?

First, I have to agree, in broad strokes, with the list of details he presents (40-year latencies, aerosol whiplash, etc.) being a pretty good description of the main “feeds and speeds” of our situation. And I do think that some people, e.g. Lester Brown, have uncovered enough of the tiles to see the full and terrifying pattern in the mosaic. But clearly not nearly enough of us have made that leap as we’re too distracted by pop culture, jobs, and who knows what to care about all aspects of our own future or that of our kids.

Second, the ocean heat issue is interesting on two fronts. We really don’t know exactly which increment of oceanic warming will set loose methane hydrates in climatically significant quantities. And yes, I think we’ve virtually guaranteed that we will have to resort to multiple geoengineering hacks to try to save ourselves in the coming decades. At that point we’ll be so far off the known map of human experience that not even the dragons will venture to follow us.

American public policy regarding climate and the environment in general is nothing short of horribly broken. The influence of corporate money, plus the bizarre, right-wing media machine currently at work, means there is very little difference any more between Democrats and Republicans in this area. I never thought I would say that, but it’s true. Call it an “all of the above” resignation.

Third, while I would find it very distasteful to see the US take action purely for reasons of economic self-interest, I would sign up for it in a heartbeat compared to the public policy toxic train wreck we have now. We are living out a bizarre scenario in which all it takes is sufficient throw-weight of money to alter public policy. Put together some ads claiming that a fictional concept like “clean coal” not only exists but is “good for American jobs” and then carpet bomb the airwaves with them, and suddenly all a politician has to do is claim to support the techno-unicorn “clean coal” and voters line up to provide support. I am at once reminded of both the old line that there’s no arguing that we’re all prostitutes, we’re just haggling over the price, as well as Harlan Ellison’s famous metaphor The Glass Teat.

[1] Yes, these figures are woefully out of date, but they still illustrate just how difficult the challenge is. To get a slightly more up to date estimate, I used the latest national averages from the CDIAC (XLS), and converted the total from thousands of tons of carbon to tons of CO2, and then used this list of country populations in 2010 to calculate per capita values. The results for various countries of interest, all values metric tons of CO2 per person per year:

  • US: 17.7
  • Australia: 16.3
  • Canada: 15.2
  • Russian Federation: 11.9
  • Germany: 9.3
  • Japan: 8.9
  • UK: 8.0
  • China: 6.2
  • France: 5.5
  • Indonesia: 2.0
  • India: 1.7

And let us not overlook this latest bit of news, which says China’s number for 2011 is 7.2 tons per capita, equally that of Europe.

[2] Of course, the merest mention of such calculations inevitably fires up the finger-pointing brigades, who then rehash the usual, very tired arguments about who “owns” which emissions. If you’re one of the sorry souls who is addicted to such parlor games, please consider: China buys coal from Australia, burns it in heavily polluting coal plants to fuel factories that make stuff to sell to Americans. Said stuff is shipped to the US on tankers fueled with Middle East oil, and then shipped from the port to the big box store in trucks running on diesel distilled from Canadian tar sands oil (cooked out of the ground with the aid of a great deal of natural gas, mind you), where it is bought by an SUV-wielding consumer who thinks he’s doing the world a favor by filling his living-room-size vehicle with E85 made from corn, at a high cost in water and food availability. When you have that all too common scenario untangled, plus a reason why the atmosphere cares about who emits which CO2 molecules, let me know.

[3] I’m also being generous and overlooking the very nasty possibility that the biosphere might not continue to absorb CO2 at its current convenient rate. The early indications are not cheering on this front: A warming ocean holds less CO2, for example, and warming could liberate some of the huge stores of carbon currently in soils (Rising carbon dioxide in atmosphere also speeds carbon loss from forest soils, IU-led research finds).

[4] In essence: The US, as an example, can’t begin to reduce our emissions to anywhere near two tons per capita (or 80% below 1990 level or whichever dauntingly difficult metric one chooses) without cleaning up our electricity generation. The numbers simply don’t support it. Similarly, we must dramatically de-carbonize our transportation system, most likely via a combination of more mass transit, better urban planning, better vehicle technology, etc. But when we start to do both, we get a positive interaction — people who buy an EV or PHEV now are likely not recharging it with carbon-free electricity. But as we clean up our electricity supply all those plug-in vehicles automagically get cleaner, even if their owners don’t even know about the changes upstream of their wall sockets.

9 comments to Assumptions

  • Just got back from a conference that included a brilliant/terrifying talk by Kevin Anderson that someone should really film. My main take-home: <4 degrees is not what happens with 'business as usual' – it's actually going to be very difficult to avoid, given current carbon pathways and sensible assumptions about developing country emission curves. The 2 degree conversation now embedded in much policy is a farce, often based on assumptions of a peak in emissions several years prior to now. We're not even able to build a governance structure able to keep up with current reality, let alone with the rapidly changing situation we're creating for ourselves.

    It's really helped me to go to an event and actually talk to other human beings in the person about this stuff. Up to now, I've got by with P3 and related blogs to not feel like I'm going mad, but there's nothing like talking with actual people. Someone over your side should organise something!

  • Lou


    Good advice (on the people-connection thing).

    I’ve seen one or more presentations (meaning slide packs, not videos or anything in person) from Anderson, and he definitely cuts right to the bone. For me, he’s squarely in the group I think of as people I desperately wish I could prove wrong, but can’t.

  • Great post. Thanks. I’m following these issues from an adaption perspective, and my confidence in having ANY sort of reasonable response (i.e., holding quality of life constant) is waning.

  • Lou


    While I didn’t express it exactly that way, your phrase “holding quality of life constant” really is the core concept I’m focused on right now.

    CC deniers love to say that we won’t cause an extinction event for humanity, which is trivially obvious. And no one worth listening to would claim that we could do such a horrific thing. What’s at risk is not the existence of humanity but the existence of modern human civilization, which is a far more fragile thing and much easier to destroy than all of humankind.

  • “The influence of corporate money, plus the bizarre, right-wing media machine currently at work, means there is very little difference any more between Democrats and Republicans in this area. I never thought I would say that, but it’s true. Call it an “all of the above” resignation.”

    I don’t see a valid basis for equating Republicans, whose leaders in Congress have called any form of carbon regulation a “national energy tax,” with Democrats, who did pass the Waxman-Markey cap-and-trade bill in the House with I believe only 8 Republican votes in support. This is just one of many examples I could cite of the dramatic differences on climate change between Democrats and Republicans.

    I think all of us who are informed realize that the passage of Waxman-Markey would not have solved the global climate crisis by itself. But I’m also struggling to see how saying that there is “little difference” anymore on climate change between Democrats and Republicans is anything but false. I believe such thinking also plays right into Republicans’ hands, as it suggests that we have absolutely no allies whatsoever in national politics, and that therefore we may as well give up on it altogether.

    I’m curious to hear your thoughts on this Lou.


    • Lou

      I should have done a better job with that comment, so let me take another swing at it here…

      My entire life I’ve vehemently resisted the idea that there’s no difference between the Red Team and the Blue Team overall or on specific issues. But my frustration at the lack of progress is so acute right now that all I can see are results — or I would if there were any. And, as long-time readers will tell you, when I get frustrated I often say things that make me cringe upon further reflection. I’m still not sure how I feel about my own statement in this case. When I feel the spark of enthusiasm for the fight, it makes me cringe. And late at night, when I’m wrapping up my online work and all I can think about is how utterly we’re failing future generations, including my three nieces, I grudgingly accept that view that politicians are all functionally the same.

      So, in light of things like W-M, are the positions of the two major US parties equivalent on CC? Certainly not. In terms of what difference it makes so far in the context of what’s needed, the evidence is distinctly underwhelming.

      So please hang in there with me, and feel free to tap me on the shoulder and offer a correction when needed. I suspect there will be plenty of opportunities in the coming months and years…

      • Thanks for your reply Lou. In terms of acute frustration with the lack of progress toward even a small fraction of what’s necessary to address the problem, I am in full agreement with you. It’s hard to imagine anything more frustrating than watching our planet sink toward permanent destruction.

        But, as you acknowledged, the distinction between Democrats and Republicans on climate change is a real one. Although the Democrats are not yet up to the task of working to do what must be done, the Republicans are utterly depraved, denying that the problem even exists. Their standard-bearer, Mitt Romney, said during the Republican primaries that “I don’t know” what is causing the climate to change. Statements like that from Republican politicians disgust me to a degree that is impossible to put into words. In contrast, if there had been enough Democrats in the Senate to prevent a Republican filibuster, Waxman-Markey could have passed. And notwithstanding all of its well-known shortcomings and flaws, it’s tough to deny that having that law on the books would have been significant, a place to start.

        Democrats may need to step up their game big time, but let’s not forget who the absolutely reprehensible villains are: Republicans.

        I look forward to following your excellent blog.


  • Kevin Anderson has an online lecture (audio + slides) recorded here:

    Depending how you slice it, my current carbon footprint is roughly 2.5-3t CO2 pa. I’m not living in a cave. But I recognise that while I believe many of the choices I’ve made make good sense even in the absence of climate concerns, not everyone is going to embrace them all very quickly. Nonetheless, I do think that attempting to shift widespread cultural assumptions on some of the big ticket items (house size, car ownership, flying, amount of “stuff” (consumer goods) purchased) is an important project, since infrastructure changes are vital, but insufficient (particularly on our very limited timeframes).

    Once again, thanks for this post. Sorry I’m a little late to the party.

  • Some rally great post Lou….