Dangerous human-made interference with climate: a GISS modelE study

Article, Other literature type, Preprint English OPEN
Hansen, J. ; Sato, M. ; Ruedy, R. ; Kharecha, P. ; Lacis, A. ; Miller, R. ; Nazarenko, L. ; Lo, K. ; Schmidt, G. A. ; Russell, G. ; Aleinov, I. ; Bauer, S. ; Baum, E. ; Cairns, B. ; Canuto, V. ; Chandler, M. ; Cheng, Y. ; Cohen, A. ; Genio, A. ; Faluvegi, G. ; Fleming, E. ; Friend, A. ; Hall, T. ; Jackman, C. ; Jonas, J. ; Kelley, M. ; Kiang, N. Y. ; Koch, D. ; Labow, G. ; Lerner, J. ... view all 47 authors (2007)
  • Publisher: European Geosciences Union
  • Journal: (issn: 1680-7324, eissn: 1680-7324)
  • Related identifiers: doi: 10.5194/acp-7-2287-2007
  • Subject: Physics - Atmospheric and Oceanic Physics | [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere | [ SDU.OCEAN ] Sciences of the Universe [physics]/Ocean, Atmosphere | Physics - Geophysics

We investigate the issue of "dangerous human-made interference with climate" using simulations with GISS modelE driven by measured or estimated forcings for 1880&ndash;2003 and extended to 2100 for IPCC greenhouse gas scenarios as well as the "alternative" scenario of Hansen and Sato (2004). Identification of "dangerous" effects is partly subjective, but we find evidence that added global warming of more than 1&deg;C above the level in 2000 has effects that may be highly disruptive. The alternative scenario, with peak added forcing ~1.5 W/m<sup>2</sup> in 2100, keeps further global warming under 1&deg;C if climate sensitivity is ~3&deg;C or less for doubled CO<sub>2</sub>. The alternative scenario keeps mean regional seasonal warming within 2&sigma; (standard deviations) of 20th century variability, but other scenarios yield regional changes of 5&ndash;10&sigma;, i.e. mean conditions outside the range of local experience. We conclude that a CO<sub>2</sub> level exceeding about 450 ppm is "dangerous", but reduction of non-CO<sub>2</sub> forcings can provide modest relief on the CO<sub>2</sub> constraint. We discuss three specific sub-global topics: Arctic climate change, tropical storm intensification, and ice sheet stability. We suggest that Arctic climate change has been driven as much by pollutants (O<sub>3</sub>, its precursor CH<sub>4</sub>, and soot) as by CO<sub>2</sub>, offering hope that dual efforts to reduce pollutants and slow CO<sub>2</sub> growth could minimize Arctic change. Simulated recent ocean warming in the region of Atlantic hurricane formation is comparable to observations, suggesting that greenhouse gases (GHGs) may have contributed to a trend toward greater hurricane intensities. Increasing GHGs cause significant warming in our model in submarine regions of ice shelves and shallow methane hydrates, raising concern about the potential for accelerating sea level rise and future positive feedback from methane release. Growth of non-CO<sub>2</sub> forcings has slowed in recent years, but CO<sub>2</sub> emissions are now surging well above the alternative scenario. Prompt actions to slow CO<sub>2</sub> emissions and decrease non-CO<sub>2</sub> forcings are required to achieve the low forcing of the alternative scenario.
  • References (138)
    138 references, page 1 of 14

    6, 12549-12610, 2006 6, 12549-12610, 2006 6, 12549-12610, 2006 6, 12549-12610, 2006 6, 12549-12610, 2006 6, 12549-12610, 2006 6, 12549-12610, 2006 Aoki, S., Yoritaka, M., and Masuyama, A.: Multidecadal warming of subsurface temperature in the Indian sector of the Southern Ocean, J. Geophys. Res., 108(C4), 8081, doi:10.1029/2000JC000307, 2003.

    Archer, D.: Fate of fossil-fuel CO2 in geologic time, J. Geophys. Res., 110, C09S05, 5 doi:10.1029/2004JC002625, 2005.

    Archer, D.: Methane hydrates and anthropogenic climate change, Rev. Geophys., in press, 2006.

    Press, Cambridge, UK, 2004.

    10 Ausubel, J.: Can technology spare the Earth?, Amer. Scientist, 84, 166-178, 1996.

    Ausubel, J.: Where is energy going?, Industrial Physicist, 6, 16-19, 2000.

    Barrett, P. J., Adams, C. J., McIntosh, W. C., Swisher, C. C., and Wilson, G. S.: Geochronological evidence supporting Antarctic deglaciation three million years ago, Nature, 359, 816-818, 1992.

    15 Bell, G. D., Goldenberg, S., Landsea, C., Blake, E., Pasch, R., Chelliah, M., and Mo, K.: Tropical storms, Bull. Amer. Meteorol. Soc., 86, S26-S29, 2005.

    Bleck, R.: An oceanic general circulation model framed in hybrid isopycnic-Cartesian Coordinates, Ocean Modelling, 4, 55-88, 2002.

    20 R., Meng, J., Sloan, L. C., Thomas, E., Wing, S. L., and Zachos, J. C.: Eocene hyperthermal event offers insight into greenhouse warming, EOS Trans. Amer. Geophys. Union, 87, 165- 169, 2006.

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