{"id":134,"date":"2005-03-15T10:19:37","date_gmt":"2005-03-15T14:19:37","guid":{"rendered":"\/?p=134"},"modified":"2007-08-16T21:13:13","modified_gmt":"2007-08-17T02:13:13","slug":"how-long-will-global-warming-last","status":"publish","type":"post","link":"https:\/\/www.realclimate.org\/index.php\/archives\/2005\/03\/how-long-will-global-warming-last\/","title":{"rendered":"How long will global warming last? Pendant combien de temps le r\u00e9chauffement global persistera-t-il ?<\/lang_fr>"},"content":{"rendered":"
\n

Guest commentary from David Archer<\/a> (U. Chicago)<\/small><\/p>\n

The notion is pervasive in the popular and scientific literature that the lifetime of anthropogenic CO2<\/sub> released to the atmosphere is some fuzzy number measured most conveniently in decades or centuries. The reality is that the CO2<\/sub> from a gallon out of every tank of gas will continue to affect climate for tens and even hundreds of thousands of years into the future.<\/p>\n


\nCommentaire invit\u00e9 par David Archer<\/a> (Univ. Chicago) (traduit par Thibault de Garidel)<\/small><\/p>\n

La notion que la dur\u00e9e de vie du CO2<\/sub> \u00e9mis dans l’atmosph\u00e8re par l’action humaine se situe entre quelques d\u00e9cennies \ufffd quelques si\u00e8cles, est omnipr\u00e9sente dans les revues de vulgarisation scientifique ainsi que celles sp\u00e9cialis\u00e9es. La r\u00e9alit\u00e9 est que chaque litre de p\u00e9trole que nous utilisons en faisant le plein de notre voiture continuera \ufffd affecter le climat pendant les prochaines dizaines et m\u00eames centaines de milliers d’ann\u00e9es.<\/p>\n

(suite…)<\/a>
\n<\/lang_fr>
\n
\nThe U.S. Environmental Protection Agency Inventory of U.S. Greenhouse Gas Emissions and Sinks (2005) has the CO2<\/sub> lifetime listed as 5-200 years, for example [1]. I have seen “hundreds of years” in scientific manuscripts and in environmentalist literature. David Goodstein in his excellent book The End of the Age of Oil states, “If we were to suddenly stop burning fossil fuel, the natural carbon cycle would probably restore the previous concentration in a thousand years or so.” I assume that Goodstein is conservatively applying several century-long e-folding times to derive his thousand years, but he implicitly assumes that the CO2<\/sub> will relax toward its 1750 concentration. The point is that it does not.<\/p>\n

When you release a slug of new CO2<\/sub> into the atmosphere, dissolution in the ocean gets rid of about three quarters of it, more or less, depending on how much is released. The rest has to await neutralization by reaction with CaCO3<\/sub> or igneous rocks on land and in the ocean [2-6]. These rock reactions also restore the pH of the ocean from the CO2<\/sub> acid spike. My model indicates that about 7% of carbon released today will still be in the atmosphere in 100,000 years [7]. I calculate a mean lifetime, from the sum of all the processes, of about 30,000 years. That’s a deceptive number, because it is so strongly influenced by the immense longevity of that long tail. If one is forced to simplify reality into a single number for popular discussion, several hundred years is a sensible number to choose, because it tells three-quarters of the story, and the part of the story which applies to our own lifetimes. <\/p>\n

However, the long tail is a lot of baby to throw out in the name of bath-time simplicity. Major ice sheets, in particular in Greenland [8], ocean methane clathrate deposits [9], and future evolution of glacial\/interglacial cycles [10] might be affected by that long tail. A better shorthand for public discussion might be that CO2<\/sub> sticks around for hundreds of years, plus 25% that sticks around forever.<\/p>\n

The sticking-around-forever idea is not new, and the picture has not changed by very much since the effect was first predicted back in 1992 [2]. You can estimate the magnitude of the effect pretty well just using CO2<\/sub> thermodynamics and the back of an envelope. It could be argued (by someone with a cruel heart) that since we don\u2019t understand why CO2<\/sub> was lower during the last ice age, we ought not go around making forecasts for the future. Well, OK, but I would point out that CO2<\/sub> in the past appears to act as an amplifier for orbitally forced climate change, so if anything, we might expect the carbon cycle in the future to amplify our own climate forcing, rather than counteract it. If the past is any guide, CO2<\/sub> surprises in the future, in the long run, seem unlikely to help us out. <\/p>\n

A long lifetime for CO2<\/sub> adjustment is also consistent with an isotopic event in the deep sea sedimentary record from 55 million years ago, the Paleocene\/Eocene Thermal Maximum event. The record tells the story of the sudden release of an isotopically light source of carbon, triggering a fast warming in the deep sea of about 5 degrees C. Both the carbon isotope signal and the temperature (inferred from oxygen isotopes) then relaxed back toward their initial values in about 100,000 years. If the released carbon were initially in the form of methane, it would have been oxidized to CO2<\/sub> within a few decades, but as CO2<\/sub> it apparently stuck around, warming the deep ocean, for a long time before it went away.<\/p>\n

The shortest lifetime estimates, such as EPA\u2019s 5-years, derive from the exchange flux of CO2<\/sub> between the atmosphere and ocean, which is about 200 Gt C\/year (1 Gt C is 1012<\/sup> kg of carbon) in each direction. Because the exchange flux is back-and-forth, it has nothing to do with the net uptake by the ocean of new CO2<\/sub> to the system, which relies on the imbalance between the upward and downward exchange fluxes. That imbalance is only about 2 Gt C\/year.<\/p>\n

Even the present-day net flux tends to underestimate the real lifetime of global warming. The atmosphere contains about 160 Gt more carbon than it did then. If we divide this number by the CO2<\/sub> invasion flux into the ocean of 2 Gt C\/year, we get an apparent uptake time scale of 80 years. This result is shorter than model air\/water equilibration time scales by a factor of four or so. I believe the problem is with the simple calculation. The CO2<\/sub> concentration of the atmosphere is going up continuously, and so it invades the ocean as it equilibrates with warm surface waters. If atmospheric CO2<\/sub> were not going up, the warm surface waters would saturate in a year or two, the overall ocean invasion rate would decrease, and the lifetime estimates by this method would increase. Different parts of the ocean equilibrate with the atmosphere on different time scales, ranging from a year for the tropical surface ocean to a millennium for the deep sea. Overall, model experiments show a CO2<\/sub> equilibration time of a few centuries [5, 6, 11, 12]. The other problem with both of these conceptions is that they implicitly assure us that the CO2<\/sub> concentration is going back to its initial concentration, which it will not.<\/p>\n

Another source of short-lifetime bias in the community probably comes from a calculation used to compare the greenhouse consequences of different gases, called the Global Warming Potential<\/a> (GWP) [13]. Some trace gases such as methane have a stronger impact on the heat balance of the earth, per molecule, than CO2<\/sub> does. However, to really compare them fairly one might want to factor in the fact that methane only lives about 10 years before it goes away (actually, it is oxidized to CO2<\/sub>, another greenhouse gas, but it is common to ignore that in GWP calculatons). Global warming potentials are calculated by integrating the radiative energy impact of a molecule of gas over its atmospheric lifetime. However, if the full lifetime of CO2<\/sub> were considered, including that long tail, then methane would be by that calculation unimportant. On human time scales, methane is certainly an important greenhouse gas, and so what’s done is to arbitrarily limit the time horizon of the calculation to something like human timescales. Methane GWP is higher when considered on the 50-year time horizon than it is on the 500-year time horizon or it would be on a 500,000-year time horizon, if anyone bothered to do that calculation. Perhaps the adoption of time horizons for GWP calculations conditions scientists to believe that CO2<\/sub> only persists for as long as this time horizon lasts. The table in the EPA document, for example, was associated with a discussion of global warming potentials. <\/p>\n

It could also be that we-who-only-live-to-be-77.2-years-old don’t want to worry about climate impacts from fossil fuel CO2<\/sub> release 100,000 or even 1,000 years from now. That would be a perfectly rational position, and I have no argument with it. Climate change negotiations are grounded in IPCC projections and scenarios to the year 2100, a far cry from the year 100,000, but even 2100 seems almost unimaginably remote given the pace of social and technological change in the world today. On the other hand, nuclear waste lasts for millions of years for some isotopes such as iodine 129. The public seems to find this information relevant, so the true longevity of anthropogenic climate change might be considered by some to be relevant to here-and-now decisions as well. At any rate, the facts as reported ought to be accurate, rather than judging in advance that no one cares about climate impacts that last thousands of years and more into the future.<\/p>\n

    \n
  1. (with the subscript “No single lifetime can be defined for CO2<\/sub> because of the different rates of uptake by different removal processes”) (EPA (2005), Inventory of U.S. Greenhouse Gas Emissions and Sinks Draft Report: 1990 -2003<\/a>, U.S. Environmental Protection Agency, Office of Atmospheric Programs<\/li>\n
  2. Walker, J.C.G. and J.F. Kasting, Effects of fuel and forest conservation on future
    \nlevels of atmospheric carbon dioxide. Palaeogeography, Palaeoclimatology, Palaeoecology (Global and Planetary Change Section), 1992. 97, 151-189.<\/li>\n
  3. Joos, F., et al., An efficient and accurate representation of complex oceanic and biospheric models of anthropogenic carbon uptake. Tellus, Ser. B, 1996. 48: p. 397-416.<\/li>\n
  4. Jain, A.K., et al., Distribution of radiocarbon as a test of global carbon cycle models. Global Biogeochem. Cycles, 1995. 9: p. 153-166.<\/li>\n
  5. Archer, D., H. Kheshgi, and E. Maier-Riemer, Multiple timescales for neutralization of fossil fuel CO2<\/sub><\/a>. Geophys. Res. Letters, 1997. 24: p. 405-408.<\/li>\n
  6. Archer, D., H. Kheshgi, and E. Maier-Reimer, Dynamics of fossil fuel CO2<\/sub> neutralization by marine CaCO3<\/sub><\/a>. Global Biogeochem. Cycles, 1998. 12: p. 259-276.<\/li>\n
  7. Archer, D., Fate of fossil-fuel CO2<\/sub> in geologic time.<\/a> J. Geophys. Res. Oceans, in press.<\/li>\n
  8. Huybrechts, P. and J. De Wolde, The dynamic response of the Greenland and Antarctic ice sheets to multiple-centure climatic warming. J. Climate, 1999. 12: p. 2169-2188.<\/li>\n
  9. Archer, D.E. and B. Buffett, Time-dependent response of the global ocean clathrate reservoir to climatic and anthropogenic forcing.<\/a> Geochem., Geophys., Geosys., 2005. 6(3): p. doi: 10.1029\/2004GC000854.<\/li>\n
  10. Archer, D. and A. Ganapolski, A movable trigger: Fossil fuel CO2<\/sub> and the onset of the next glaciation. <\/a>Geochem., Geophys., Geosys., in press.<\/li>\n
  11. Sarmiento, J.L., U. Siegenthaler, and J.C. Orr, A perturbation simulation of CO2<\/sub> uptake in an ocean general circulation model. J. Geophys. Res., 1992. 97: p. 3621-3645.<\/li>\n
  12. Sarmiento, J.L. and C.L. Qu\u00e9r\u00e9, Oceanic carbon dioxide uptake in a model of century-scale global warming. Science, 1996. 274: p. 1346-1350.<\/li>\n
  13. Jain, A.K., et al., Radiative forcings and global warming potentials of 39 greenhouse gases. J. Geophysical Res., 2000. 105(D16): p. 20,773-20,790.<\/li>\n<\/ol>\n


    \nL’agence am\u00e9ricaine de protection de l’environnement (EPA) estime par exemple la dur\u00e9e de vie du CO2<\/sub> entre 5 et 200 ans, dans son inventaire des sources et puits de gaz a effet de serre aux USA [1]. J’ai \u00e9galement vu des “centaines d’ann\u00e9es” dans des articles scientifiques et dans la litt\u00e9rature “environnementaliste”. David Goodstein dans son excellent livre “The End of the Age of Oil” dit : ” si nous nous arr\u00eations brusquement de consommer du carbone fossile, le cycle naturel du carbone restaurerait la concentration initiale en environ un millier d’ann\u00e9es”. J’imagine que Goodstein applique conservativement quelques si\u00e8cles multipli\u00e9s par un facteur donn\u00e9 pour d\u00e9river son millier d’ann\u00e9es, mais il fait l’hypoth\u00e8se implicite que la concentration atmosph\u00e9rique en CO2<\/sub> reviendra a son niveau de 1750. Le probl\u00e8me c’est que ce n’est pas le cas.<\/p>\n

    Quand vous \u00e9mettez une dose de CO2<\/sub> “neuf” [NdT: dans le sens nouveau dans le cycle du Carbone ; ce carbone “neuf” est en r\u00e9alit\u00e9 du carbone tr\u00e8s ancien, fossilis\u00e9 sous forme de p\u00e9trole ou de gaz<\/i>] dans l’atmosph\u00e8re, environ les trois quarts sont dissous dans l’oc\u00e9an et disparaissent, en fonction de la quantit\u00e9 \u00e9mise. Le quart restant reste \ufffd \u00eatre neutralis\u00e9 en r\u00e9agissant avec les roches ign\u00e9es ou carbonat\u00e9es sur terre et dans les oc\u00e9ans. Les r\u00e9actions avec ces roches restaurent \u00e9galement le pH de l’oc\u00e9an du pic acide li\u00e9 au CO2<\/sub>. Mon mod\u00e8le indique qu’environ 7% du carbone \u00e9mis de nos jours, y sera toujours dans 100 000 ans [7]. Mon estimation de la dur\u00e9e de vie, \ufffd partir de tous les processus en jeu, est d’environ 30 000 ans. C’est un chiffre d\u00e9cevant car il est tr\u00e8s influenc\u00e9 par la lenteur de ces r\u00e9actions qui forment une “queue”. N\u00e9anmoins, s’il faut choisir un chiffre afin de simplifier les discussions avec le grand public, alors le choix de quelques centaines d’ann\u00e9es est raisonnable car il prend en compte les trois quarts de l’histoire, et la partie qui nous affecte nous et nos dur\u00e9es de vie.<\/p>\n

    N\u00e9anmoins, il est exag\u00e9r\u00e9 de ne pas prendre en compte cette “queue” sous le pr\u00e9texte de la vulgarisation. Les principales calottes de glaces, en particulier au Groenland [8], les d\u00e9p\u00f4ts de clathrate de m\u00e9thane [9], et l’\u00e9volution future des cycles glaciaires\/interglaciaires [10] peuvent \u00eatre affect\u00e9s par cette longue “queue”. Une image plus juste pour le grand public est donc que le CO2<\/sub> \u00e9mis reste environ quelques centaines d’ann\u00e9es, alors que 25% reste ind\u00e9finiment.<\/p>\n

    L’id\u00e9e que cette dur\u00e9e de r\u00e9sidence est extr\u00eamement longue n’est pas nouvelle, et notre compr\u00e9hension n’a pas beaucoup chang\u00e9 depuis que cet effet a \u00e9t\u00e9 pour la premi\u00e8re fois pr\u00e9dit en 1992 [2]. Il est possible d’estimer la magnitude de cet effet en utilisant simplement la thermodynamique du CO2<\/sub>. Il peut \u00eatre \u00e9galement avanc\u00e9 que comme nous ne connaissons pas pourquoi le CO2<\/sub> \u00e9tait moins \u00e9lev\u00e9 pendant la derni\u00e8re p\u00e9riode glaciaire, nous ferions mieux de ne pas faire de pronostics pour le futur. Ce \ufffd quoi je r\u00e9pondrais, que le CO2<\/sub> semble jouer le r\u00f4le d’un amplificateur des changements climatiques forc\u00e9s par les param\u00e8tres orbitaux, et qu’en tout \u00e9tat de cause, nous devons nous attendre \ufffd ce que le cycle du carbone amplifiera encore plus notre propre for\u00e7age climatique, plut\u00f4t que l’att\u00e9nuer. Si le pass\u00e9 peut nous servir de guide, \ufffd long terme, les surprises du CO2<\/sub> \ufffd l’avenir ne risquent pas de nous aider beaucoup.<\/p>\n

    Une longue dur\u00e9e de vie pour le CO2<\/sub> est \u00e9galement compatible avec un \u00e9v\u00e9nement isotopique enregistr\u00e9 dans les s\u00e9diments oc\u00e9aniques il y a environ 55 millions d’ann\u00e9es, l”Optimum thermique Pal\u00e9ocene\/Eocene” – (Paleocene\/Eocene Thermal Maximum). Ces s\u00e9diments r\u00e9v\u00e8lent qu’un relargage abrupt de carbone dont les isotopes les plus l\u00e9gers \u00e9taient abondants, a d\u00e9clench\u00e9 un rechauffement rapide des masses d’eau oc\u00e9aniques profondes d’environ 5 degr\u00e9s Celsius. Il a fallu attendre environ 100 000 ans pour que le signal isotopique du carbone et la temp\u00e9rature (d\u00e9duite des isotopes de l’oxyg\u00e8ne) reviennent \ufffd des concentrations similaires \ufffd celles initiales. M\u00eame si le carbone relargu\u00e9 \u00e9tait principalement sous forme de m\u00e9thane, il aurait du s’oxyder sous forme de CO2<\/sub> en quelques d\u00e9cennies, mais apparemment, il est rest\u00e9 comme le CO2<\/sub> suffisamment longuement pour permettre de r\u00e9chauffer les eaux profondes avant qu’il ne s’en aille.<\/p>\n

    Les dur\u00e9es de vie les plus courtes, telles que l’estimation de 5 ans faite par l’EPA, est d\u00e9duite du flux d’\u00e9change de CO2<\/sub> entre atmosph\u00e8re et oc\u00e9an, qui est d’environ 200 Gt C\/an (1 Gigatonne de Carbone correspond a 1012<\/sup>kg de carbone) dans chaque direction. Comme les \u00e9changes entre oc\u00e9an et atmosph\u00e8re fonctionnent \ufffd double-sens, ceci n’a pas d’implications sur l’absorption par l’oc\u00e9an du”nouveau” CO2 [NdT: anthropog\u00e9nique], qui d\u00e9pend du d\u00e9s\u00e9quilibre entre les flux entrant et sortant. Ce d\u00e9s\u00e9quilibre n’est que de 2Gt C\/an.<\/p>\n

    M\u00eame les flux nets modernes ont tendance \ufffd sous-estimer la dur\u00e9e de vie r\u00e9elle du r\u00e9chauffement global. L’atmosph\u00e8re contient environ 160 Gt C qu’il ne contenait auparavant [NdT: avant l’\u00e8re industrielle, ~1850 ap JC]. Si on divise simplement ce nombre par le flux entrant de CO2 dans l’oc\u00e9an de 2Gt C\/an, on obtient une dur\u00e9e d’assimilation d’environ 80 ans. Ce r\u00e9sultat est environ 4 fois plus court que les \u00e9chelles de temps d’\u00e9quilibrage entre oc\u00e9an et atmosph\u00e8re mod\u00e9lis\u00e9es. Je pense que le probl\u00e8me r\u00e9sulte de la simplicit\u00e9 du calcul. La concentration atmosph\u00e9rique en CO2 ne cesse d’augmenter, et envahie \u00e9galement l’oc\u00e9an comme dans les r\u00e9gions chaudes de l’oc\u00e9an. Si la concentration atmosph\u00e9rique en CO2 cessait d’augmenter, les eaux chaudes de l’oc\u00e9an seraient satur\u00e9es en une ann\u00e9e ou deux, le taux de p\u00e9n\u00e9tration du CO2 dans l’oc\u00e9an decroitrait en retour, et par cons\u00e9quent l’estimation de la dur\u00e9e de vie de carbone par cette m\u00e9thode augmenterait. Les diff\u00e9rentes r\u00e9gions de l’oc\u00e9an atteignent un \u00e9quilibre avec l’atmosph\u00e8re \ufffd diff\u00e9rentes \u00e9chelles de temps, allant de l’ann\u00e9e pour les masses d’eaux de surface de l’oc\u00e9an tropical au millier d’ann\u00e9es pour les masses d’eaux de l’oc\u00e9an profond. G\u00e9n\u00e9ralement, les simulations num\u00e9riques d\u00e9montrent que le temps de mise a l’\u00e9quilibre du CO2<\/sub> est d’environ de quelques si\u00e8cles [5, 6, 11, 12]. Un probl\u00e8me suppl\u00e9mentaire pour ces deux estimations diff\u00e9rentes est qu’elles nous indiquent implicitement que la concentration en CO2<\/sub> va revenir \ufffd sa concentration initiale, ce qui n’est pas le cas.<\/p>\n

    L’utilisation d’un calcul permettant de comparer les cons\u00e9quences des diff\u00e9rents gaz \ufffd effet de serre, nomm\u00e9es le potentiel de r\u00e9chauffement global<\/i> (GWP), permet \u00e9galement d’estimer la dur\u00e9e de vie du carbone, estimations biais\u00e9es vers des valeurs basses. Certains gaz ont un effet par mol\u00e9cule, beaucoup plus fort sur le bilan thermique global ; le m\u00e9thane, par exemple, a un potentiel beaucoup plus important que le CO. N\u00e9anmoins, pour effectuer un calcul raisonnable, il faut prendre en compte le fait que le m\u00e9thane a une dur\u00e9e de vie d’environ 10 ans avant qu’il ne soit transform\u00e9 (le m\u00e9thane est en fait oxyd\u00e9 en CO2, un autre gaz a effet de serre, mais cet effet est souvent ignor\u00e9 dans les calculs de GWP). Les diff\u00e9rents potentiels de r\u00e9chauffement global sont calcul\u00e9s en int\u00e9grant l’impact radiatif d’une mol\u00e9cule pendant toute sa dur\u00e9e de vie dans l’atmosph\u00e8re. N\u00e9anmoins, si la dur\u00e9e de vie compl\u00e8te du CO2<\/sub> \u00e9tait prise en compte, en incluant cette longue “queue”, alors le m\u00e9thane serait en comparaison n\u00e9gligeable. Sur une \u00e9chelle de temps humaine, le m\u00e9thane est certainement un gaz a effet de serre important, et c’est pour cette raison que les limites du calculs sont souvent born\u00e9es \ufffd des \u00e9chelles de temps comparables a celles de la dure de vie des hommes. Le GWP du m\u00e9thane est beaucoup plus fort a un horizon de 50 ans, qu’a un horizon de 500 ans, ou qu’il ne doit \u00eatre a un horizon de 500 000 ans si quelqu’un avait fait le calcul. L’adoption de limites temporelles pour les calculs de GWP conditionne peut \u00eatre les scientifiques a croire que le CO2 ne persiste que dans la limite temporelle pr\u00e9alablement fix\u00e9e pour ce calcul. Le tableau dans le rapport de l’EPA, \u00e9tait ainsi associ\u00e9 \ufffd une discussion des potentiels de r\u00e9chauffement global. <\/p>\n

    Il est \u00e9galement possible, que nous-m\u00eames dont l’esp\u00e9rance de vie est de 77.2 ans [aux USA] ne voulons pas nous soucier des impacts climatiques de notre consommation de carbone fossile dans 100 000 ou m\u00eame 1000 ans. C’est une posture parfaitement rationnelle, pour laquelle je n’ai pas d’opposition. Les n\u00e9gociations sur l’\u00e9volution du climat sont bas\u00e9es sur des projections et sc\u00e9narios du GIEC \ufffd l’horizon 2100, bien avant l’an 100 000. Mais m\u00eame 2100 appara\u00eet comme \u00e9tant inimaginablement distant en regard de la vitesse des changements sociaux et technologiques modernes. D’un autre cot\u00e9, les d\u00e9chets nucl\u00e9aires persistent pour des millions d’ann\u00e9es pour certains radioisotopes comme l’iode 129. Le public semble trouver cette information pertinente, ainsi la v\u00e9ritable long\u00e9vit\u00e9 des changements climatiques dus \ufffd l’action humaine peut \u00e9galement \u00eatre consid\u00e9r\u00e9 comme tout aussi pertinente pour prendre des d\u00e9cisions imm\u00e9diates. Dans tous les cas, les faits report\u00e9s doivent \u00eatre justes, plut\u00f4t qu’issus du pr\u00e9jug\u00e9 que personne ne se soucie d’impacts climatiques \ufffd venir qui dureront des milliers d’ann\u00e9es et plus.<\/p>\n

      \nR\u00e9f\u00e9rences :<\/p>\n
    1. (with the subscript “No single lifetime can be defined for CO2<\/sub> because of the different rates of uptake by different removal processes”) (EPA (2005), Inventory of U.S. Greenhouse Gas Emissions and Sinks Draft Report: 1990 -2003<\/a>, U.S. Environmental Protection Agency, Office of Atmospheric Programs<\/li>\n
    2. Walker, J.C.G. and J.F. Kasting, Effects of fuel and forest conservation on future
      \nlevels of atmospheric carbon dioxide. Palaeogeography, Palaeoclimatology, Palaeoecology (Global and Planetary Change Section), 1992. 97, 151-189.<\/li>\n
    3. Joos, F., et al., An efficient and accurate representation of complex oceanic and biospheric models of anthropogenic carbon uptake. Tellus, Ser. B, 1996. 48: p. 397-416.<\/li>\n
    4. Jain, A.K., et al., Distribution of radiocarbon as a test of global carbon cycle models. Global Biogeochem. Cycles, 1995. 9: p. 153-166.<\/li>\n
    5. Archer, D., H. Kheshgi, and E. Maier-Riemer, Multiple timescales for neutralization of fossil fuel CO2<\/sub><\/a>. Geophys. Res. Letters, 1997. 24: p. 405-408.<\/li>\n
    6. Archer, D., H. Kheshgi, and E. Maier-Reimer, Dynamics of fossil fuel CO2<\/sub> neutralization by marine CaCO3<\/sub><\/a>. Global Biogeochem. Cycles, 1998. 12: p. 259-276.<\/li>\n
    7. Archer, D., Fate of fossil-fuel CO2<\/sub> in geologic time.<\/a> J. Geophys. Res. Oceans, in press.<\/li>\n
    8. Huybrechts, P. and J. De Wolde, The dynamic response of the Greenland and Antarctic ice sheets to multiple-centure climatic warming. J. Climate, 1999. 12: p. 2169-2188.<\/li>\n
    9. Archer, D.E. and B. Buffett, Time-dependent response of the global ocean clathrate reservoir to climatic and anthropogenic forcing.<\/a> Geochem., Geophys., Geosys., 2005. 6(3): p. doi: 10.1029\/2004GC000854.<\/li>\n
    10. Archer, D. and A. Ganapolski, A movable trigger: Fossil fuel CO2<\/sub> and the onset of the next glaciation. <\/a>Geochem., Geophys., Geosys., in press.<\/li>\n
    11. Sarmiento, J.L., U. Siegenthaler, and J.C. Orr, A perturbation simulation of CO2<\/sub> uptake in an ocean general circulation model. J. Geophys. Res., 1992. 97: p. 3621-3645.<\/li>\n
    12. Sarmiento, J.L. and C.L. Qu\u00e9r\u00e9, Oceanic carbon dioxide uptake in a model of century-scale global warming. Science, 1996. 274: p. 1346-1350.<\/li>\n
    13. Jain, A.K., et al., Radiative forcings and global warming potentials of 39 greenhouse gases. J. Geophysical Res., 2000. 105(D16): p. 20,773-20,790.<\/li>\n<\/ol>\n

      <\/sub2><\/lang_fr><\/p>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

      Guest commentary from David Archer (U. Chicago) The notion is pervasive in the popular and scientific literature that the lifetime of anthropogenic CO2 released to the atmosphere is some fuzzy number measured most conveniently in decades or centuries. The reality is that the CO2 from a gallon out of every tank of gas will continue […]<\/p>\n","protected":false},"author":41,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[1,3,2],"tags":[],"class_list":{"0":"post-134","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-climate-science","7":"category-greenhouse-gases","8":"category-paleoclimate","9":"entry"},"aioseo_notices":[],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/posts\/134","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/users\/41"}],"replies":[{"embeddable":true,"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/comments?post=134"}],"version-history":[{"count":0,"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/posts\/134\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/media?parent=134"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/categories?post=134"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/tags?post=134"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}