Carbon is forever: Fossil CO2 impacts will outlast Stonehenge and nuclear waste

Every few years, people need to be reminded that carbon dioxide released into the atmosphere from fossil fuel combustion lasts a long, long, long time. How long?

A 2005 study by Geophysicist David Archer, “Fate of fossil fuel CO2 in geologic time,” (subs. req’d.) concluded that a large fraction of the CO2 emitted by humans last well in excess of 1000 years:

The mean lifetime of anthropogenic CO2 is dominated by the long tail, resulting in a range of 30–35 kyr.

That’s why we need to stop and reverse the growth of fossil fuel emissions immediately (see “Dr. Hansen to Dr. Merkel: Carbon is forever — so ban new traditional coal plants now“). That’s why we can’t have climate regulations that let companies keep burning coal while they buy rip-offsets.

In the interest of reminding people of this central fact of climate science, Nature online has published, “Carbon is forever.” Turns out Archer has a book out, The Long Thaw: How Humans Are Changing the Next 100,000 Years of Earth’s Climate, which has this useful figure:

Unfortunately we are unable to provide accessible alternative text for this. If you require assistance to access this image, or to obtain a text description, please contact

Figure: Model simulation of atmospheric CO2 concentration for 40,000 years following after a large CO2 release from combustion of fossil fuels. Different fractions of the released gas recover on different timescales.

So we’re in the process of changing the climate (for the much, much worse) for 100,000 years. Hmm. I’ve been saying that if we don’t act now we’re going to ruin the climate for the next 50 generations to walk the planet. I guess I was being way too conservative (again).

“The climatic impacts of releasing fossil fuel CO2 to the atmosphere will last longer than Stonehenge,” Archer writes. “Longer than time capsules, longer than nuclear waste, far longer than the age of human civilization so far.”

It’s not just the carbon that could last forever:

The warming from our CO2 emissions would last effectively forever, too. A recent study by Caldeira and Damon Matthews of Concordia University in Montreal found that regardless of how much fossil fuel we burn, once we stop, within a few decades the planet will settle at a new, higher temperature. As Caldeira explains, “It just increases for a few decades and then stays there” for at least 500 years — the length of time they ran their model. “That was not at all the result I was expecting,” he says.

Bottom line: It’s great that one form of solid carbon is forever, as Shirley Bassey sings in the classic Bond movie, but not that the gaseous form is.

In other words, a few decades of prevention is worth 30,000 years of cure.

“The science is beyond dispute… Delay is no longer an option. Denial is no longer an acceptable response.”


21 Responses to Carbon is forever: Fossil CO2 impacts will outlast Stonehenge and nuclear waste

  1. Zed says:

    There is no possible way to immediately stop all CO2. We can try as hard as we like, and we will make strides will be made if we kick and scream and fight every step of the way, but there will still be excess CO2 that needs to be handled.

    This leads me to say that another program needs to be tacked onto our already long list: planting trees. Lots and lots of trees. This can function as a stopgap until a device is created that can remove CO2 from the atmosphere.

    Maybe I sound ridiculous, but at this point, I don’t think so.

  2. jorleh says:

    Rather interesting to see Obama´s action. It is not enough to drop CO2 emissions 10 % in two decades. And in any case Obama rules only eight years. So we can tell only in eight years periods.

  3. Nice post Joe,

    While the present policy debate on climate change focuses on 2020, 2050 and 2100 targets, we rarely recognise that our present use of fossil fuels will continue to affect the atmosphere and the oceans for many, many thousands of years.

    Archer (2005) suggested an appropriate approximation of the lifetime of CO2 released by the burning of fossil fuels for public discussion is “300 years, plus 25% that lasts forever”.

    We commonly think of our children and grandchildren to appreciate the consequences of our present actions but as our present emissions of fossil fuel will continue to affect the atmosphere for over 100,000 years, we should appreciate the decisions on climate policies today will affect the next 5,000 generations of humanity and beyond.

  4. llewelly says:

    The graph assumes we’ll peak at 1500 ppm. Without carbon cycle feedbacks, the A1FI scenario only results in 950 ppm by 2100. I can’t find any information on post-2100 A1FI projections along the lines of SRES, but it looks to me like David Archer’s 1500 ppm peak (which comes from assuming all conventional fossil fuels are burned) is equivalent to no effective mitigation until 2100. That seems very unlikely. (The path we’re on now is slightly lower emissions than A1FI, but we’ve already started to burn some of the unconventional fossil fuels. But given current policy promises, and current actions, it seems unlikely so little will be done.) Archer is right to bring up the burn baby burn scenario (as its impact makes its risks disproportionate to its probability of occurring) , but it’s unfortunate the article that doesn’t provide graphs for the potential results of other scenarios.

    On the pessimistic side – positive carbon cycle feedbacks look more likely than they did a few years ago, and it would be nice to see projections which include potential carbon cycle feedbacks. (I suppose one could treat Archer’s 1500 ppm peak as a result of about 550 ppm of future human activities, and about 550 ppm of future carbon cycle positive feedbacks. I don’t consider that scenario likely either, but again, its impact makes its risks disproportionate to its probability of occurring.)

    I’ll check out his book as soon as I can.

  5. paulm says:

    Its nice to know that Obama & Hillary seem to be listing Climate Change as 2nd (some times 3rd depending on audience) on their list every time I hear talking on problems.

    Obama Introduces Clinton, National Security Team

  6. Ronald says:


    The idea to plant lots of trees and have that soak up all the carbon dioxide from the atmosphere is in the right place, but it doesn’t do it fast enough. Somewhere I read we’d need 7 earths to have enough trees to do the job. There are some other ideas such as biochar, which will partially burn biomass until you get only carbon and then bury it in the ground. But then why go thru all the trouble of collecting biomass to bury carbon, just don’t dig up the coal in the first place. Maybe it’s cheaper some places to gather biomass than other places for non-carbon fueled energy.
    The idea is trees are to slow growing.

  7. G.R.L. Cowan says:

    Romm and Zed seem to share an agenda of ignoring the fact that industrial-scale removal of CO2

  8. paulm says:

    This is why statements like this are bizarre …

    Climate change watchdog backs expansion of Heathrow
    Nov 27 2008:

    Third runway is compatible with government’s greenhouse gas targets, says Climate Change Committee chairman

  9. G.R.L. Cowan says:

    Romm and Zed seem to share an agenda of ignoring the fact that industrial-scale removal of CO2 from the atmosphere has already been demonstrated.

    Also see and/or google (oman peridotite).

  10. Brendan says:

    Joe, could you comment on what the graph means by “Ocean Invasion”? I’m curious, because if it means an ocean feedback loop with sucking up the carbon, aren’t there lots of reports of that already being maxed out? This would imply to me that we can’t come back from 1500 ppm without destroying the oceans as we know it.

  11. Bob Wallace says:

    G.R.L. – “demonstrated”?

    Demonstrated in concept, or demonstrated on a practical scale?

    Hot dry rock geothermal has been demonstrated to the extent that there are two very small plants hooked to the grid. Whether the technology can be scaled up to provide affordable power worldwide is still under investigation.

  12. Jay Alt says:

    Featured article –
    Long term fate of anthropogenic carbon

    The paper below has the graph with discussion of it. ‘Invasion’ refers to the deep ocean coming into equilibrium with atmospheric CO2.

    The millennial atmospheric lifetime of anthropogenic CO2

  13. Bob Wright says:

    Thee has been research on minerals that will react with CO2. Maybe this one, or bubbling stack gas through lagoons of slurried Mg-Silicate minerals.

    Fast growth tree plantations might help:

    Future green jobs: Mining olivine and tree farming for thousands of years?

  14. David B. Benson says:

    G.R.L. Cowan is correct. Methods for permanent removal of unwanted carbon exist. Enhanced weathring of olivine appears to be (one of) the least expensive methods; I estimate $20–25 per tonne of carbon dioxide removed from the air.

    But note that in 2007 CE we added about 37 billion tonnes of excess carbon dioxide to the atmosphere.

  15. David B. Benson says:

    and ocean and land and biomass. The 37 billion figure is emissions for the year.

  16. alex says:

    The UK has a plan – 80% reduction by 2050.

    Mind you, what’s the point if the US and China don’t do the same.

  17. alex says:

    Judging by the comments to this Daily Mail article, not everyone is on board. The Daily Mail is right up there with Bush when it comes to combatting climate change.

  18. Bob Wallace says:

    Notice: This comment is not necessarily germane to the above discussion, nor is it intended to be a reflection on any who have posted. It’s just a thought that I haven’t been able to shake since taking a quick read through all of this, a thought that I wanted to record for the future.

    That said…

    I’m wondering if stage three of “teh skeptics” – you know the folks who began with “The Earth is not warming”, then moved to “OK, the Earth is warming, but not because of mankind putting lots of carbon in the atmosphere”- those folks, ….

    I’m wondering if state three is going to be “OK, the Earth is warming because mankind put lots of carbon in the atmosphere, but we can keep on driving our Caddies and we can get it out by ….” and then promoting some incredible solution. Probably powered by coal….


    Sorry for the interruption….

  19. Zed says:

    Oh my. I have an ‘agenda’. You could at least be insulting instead of paranoid and call me ‘ignorant’. It would be a more accurate statement.

  20. G.R.L. Cowan says:

    Apologies to Zed. I tend to assume everyone has been paying attention for years and years.

    — G.R.L. Cowan (‘How fire can be tamed’)