Abrupt climate change at the end of the last glacial period inferred from trapped air in polar ice

Science

Volumn 286, Issue 5441, 1999, Pages 930-934

  Severinghaus, Jeffrey P ^a   Brook, Edward J ^b  

^a UNIVERSITY OF CALIFORNIA   (United States)

^b WASHINGTON STATE UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ARGON; NITROGEN;

CLIMATE CHANGE; ICE CORE; LAST GLACIAL; PALEOCLIMATE;

AIR TEMPERATURE; ARCTIC CLIMATE; ARTICLE; GEOGRAPHIC DISTRIBUTION; GREENHOUSE EFFECT; GREENLAND; NATURAL SCIENCE; PRIORITY JOURNAL;

GREENLAND;

EID: 0033615503     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.286.5441.930     Document Type: Article

References (61)

1. W. Dansgaard, J. W. C. White, S. J. Johnsen, Nature 339, 532 (1989); S. J. Johnsen et al., Nature 359, 311 (1992).
2. W. Dansgaard, J. W. C. White, S. J. Johnsen, Nature 339, 532 (1989); S. J. Johnsen et al., Nature 359, 311 (1992).
3. P. M. Grootes et al., Nature 366, 552 (1993).
4. R. B. Alley et al., Nature 362, 527 (1993).
5. K. C. Taylor et al., Nature 361, 432 (1993).
6. M. Stuiver, P. M. Grootes, T. F. Braziunas, Quat. Res. 44, 341 (1995).
7. K. C. Taylor et al., Science 278, 825 (1997).
8. J. P. Severinghaus et al., Nature 391, 141 (1998).
9. T. J. Crowley and C. R. North, Paleoclimatology (Oxford Univ. Press, New York, 1991).
10. L. G. Thompson et al., Science 282, 1858 (1998).
11. J. L. Debeaulieu and M. Reille, Quat. Sci. Rev. 11, 431 (1992).
12. N. Koc and E. Jansen, Geology 22, 523 (1994).
13. G. C. Bond and R. Lotti, Science 267, 1005 (1995).
14. R. J. Behl and J. P. Kennett, Nature 379, 243 (1996).
15. H. Schulz, U. vonRad, H. Erlenkeuser, Nature 393, 54 (1998).
16. K. A. Hughen et al., Nature 380, 51 (1996).
17. E. J. Brook, T. Sowers, J. Orchardo, Science 273, 1087 (1996).
18. J. Chappellaz et al., Nature 366, 443 (1993).
19. E. J. Steig et al., Science 282, 92 (1998).
20. T. Blunier et al., Geophys. Res. Lett. 24, 2683 (1997).
21. P. Martinerie, G. P. Brasseur, C. Granier, J. Geophys. Res. 100, 14291 (1995).
22. E. J. Brook, J. P. Severinghaus, S. Harder, M. Bender, in Mechanisms of Global Climate Change at Millennial Time Scales, Geophysical Monograph Ser., vol. 112 (American Geophysical Union, Washington, DC, 1999), pp. 165-176.
23. A. Dallenbach et al., Geophys. Res. Lett., in press.
24. -1 (21, 22). Brook et al. (21) reported a larger increase in tropical source at this time, based on data that indicate a greater contribution from boreal sources before the Bølling Transition. Those data, from the Taylor Dome ice core, did not include the time period immediately before the Bølling warming (the Older Dryas), where it appears that the contribution from boreal sources was lower.
25. R. G. Prinn et al., Science 269, 187 (1995).
26. J. Schwander, B. Stauffer, A. Sigg, Ann. Glaciol. 10, 141 (1988).
27. T. A. Sowers, M. L. Bender, D. Raynaud, J. Geophys. Res. 94, 5137 (1989).
28. P. J. Fawcett, A. M. Ágústsdóttir, R. B. Alley, C. A. Shuman, Paleoceanography 12, 23 (1997).
29. E. A. Boyle, Geophys. Res. Lett. 24, 273 (1997).
30. C. D. Charles, D. Rind, J. Jouzel, R. D. Koster, R. G. Fairbanks, Science 263, 508 (1994).
31. K. M. Cuffey et al., Science 270, 455 (1995); D. Dahl-Jensen et al., Science 282, 268 (1998).
32. K. M. Cuffey et al., Science 270, 455 (1995); D. Dahl-Jensen et al., Science 282, 268 (1998).
33. R. G. Fairbanks, Paleoceanography 5, 937 (1990).
34. 14N, so the methane signal will traverse the firn in about 1 year less than the nitrogen signal, but we neglect this difference.
35. F. A. Lindemann and F. W. Aston, Philos. Mag. Ser. 6 37, 523 (1919); H. Craig, Y. Horibe, T. Sowers, Science 242, 1675 (1988); J. Schwander, in The Environmental Record in Glaciers and Ice Sheets, H. Oeschger and C. C. Langway Jr., Eds. (Wiley, New York, 1989), pp. 53-67.
36. F. A. Lindemann and F. W. Aston, Philos. Mag. Ser. 6 37, 523 (1919); H. Craig, Y. Horibe, T. Sowers, Science 242, 1675 (1988); J. Schwander, in The Environmental Record in Glaciers and Ice Sheets, H. Oeschger and C. C. Langway Jr., Eds. (Wiley, New York, 1989), pp. 53-67.
37. F. A. Lindemann and F. W. Aston, Philos. Mag. Ser. 6 37, 523 (1919); H. Craig, Y. Horibe, T. Sowers, Science 242, 1675 (1988); J. Schwander, in The Environmental Record in Glaciers and Ice Sheets, H. Oeschger and C. C. Langway Jr., Eds. (Wiley, New York, 1989), pp. 53-67.
38. S. Chapman and F. W. Dootson, Philos. Mag. 33, 248 (1917).
39. K. E. Grew and T. I. Ibbs, Thermal Diffusion in Gases (Cambridge Univ. Press, Cambridge, 1952).
40. c).
41. W. S. B. Paterson, The Physics of Glaciers (Pergamon, Tarrytown, NY, 1969).
42. The amount of smoothing can be calculated from the age distribution of the gases in the firn, which has a width of about a decade (25). Thus, the smoothing imparted by diffusion in the firn has roughly the same impact as a 10-year running average. Additional smoothing may result from the fact that the bubbles do not all dose off at the same time, but the importance of this effect in GISP2 is currently unknown.
43. J. Schwander et al., J. Geophys. Res. 102, 19483 (1997).
44. 4 in samples from the same depth.
45. 40Ar/4.
46. D. A. Meese et al., J. Geophys. Res. 102, 26411 (1997).
47. One potential criticism of this argument arises from uncertainty in the chronology of the Taylor Dome ice core. The timing of the methane rise in Taylor Dome ice is independently dated to no better than ±300 years. Thus, the methane rise observed in Taylor Dome arguably could have occurred 300 years after the rise in GISP2, a scenario we dub the "Boreal burst." During the interval between the boreal and austral methane increases, the interpolar gradient would have been equal to the difference between Bølling and Oldest Dryas concentrations, or 25%. To maintain this exceptionally steep gradient, atmospheric transport must have been substantially reduced relative to today or the austral sink radically enhanced, starting at the time of the boreal methane rise and fortuitously stopping at the time of the austral methane rise. Thus, we argue that the Boreal burst scenario is extremely unlikely.
48. S. Frolking and P. Crill, Global Biogeochem. Cycles 8, 385 (1994).
49. W. S. Broecker and C. H. Denton, Geochim. Cosmochim. Acta 53, 2465 (1989); S. Manabe and R. J. Stouffer, Nature 378, 165 (1995); S. Rahmstorf, Nature 378, 145 (1995).
50. W. S. Broecker and C. H. Denton, Geochim. Cosmochim. Acta 53, 2465 (1989); S. Manabe and R. J. Stouffer, Nature 378, 165 (1995); S. Rahmstorf, Nature 378, 145 (1995).
51. W. S. Broecker and C. H. Denton, Geochim. Cosmochim. Acta 53, 2465 (1989); S. Manabe and R. J. Stouffer, Nature 378, 165 (1995); S. Rahmstorf, Nature 378, 145 (1995).
52. A. M. Ágústsdóttir, R. B. Alley, D. Pollard, W. H. Peterson, Geophys. Res. Lett. 26, 1333 (1999).
53. P. A. Mayewski et al., Science 263, 1747 (1994).
54. S. W. Hosteller, P. U. Clark, P. J. Bartlein, A. C. Mix, N. J. Pisias, J. Geophys. Res. 104, 3947 (1999). We speculate that abrupt warming in the North Atlantic basin may have stimulated the Asian monsoon by the decrease in continental albedo associated with reduced snow cover and greening of desert in downwind Eurasia.
55. ice. The bottom boundary of the heat model was held at 1000 m to account for the thermal inertia of the ice. The bottom boundary of the gas model is impermeable and held constant at 95-m depth, the firn depth inferred from the Herron-Langway model (53) with an accumulation rate of 0.07 m of ice per year and a temperature of -47.5°C (51).
56. M. Battle et al., Nature 383, 231 (1996).
57. K. Cuffey and G. Clow, J. Geophys. Res. 102, 26383 (1997).
58. R. B. Alley and B. R. Koci, Ann. Glaciol. 14, 6 (1990).
59. M. M. Herron and C. C. Langway, J. Glaciol. 25, 373 (1980).
60. M. Bender et al., Nature 372, 663 (1994).
61. 15N measurements at SlO; and R. Alley, T. Sowers, R. Keeling, D. Jacob, L. Talley, and S. Harder for helpful discussions. This work was supported by NSF grants OPP 9725305 (J.P.S.) and OPP 9725918 (E.J.B.).