The International Ad Hoc Detection and Attribution Group (IDAG) is a self-organized group of climate experts interested in the problem of the detection and attribution of externally forcing climate signals in the observations. This report, like our others, expresses our collective views and not those of any international or national agency. While most of the Group obtains funding from their normal sources, we wish to acknowledge the Climate Change Detection and Attribution Project, a jointly funded effort by NOAA’s Office of Global Programs and the Department of Energy’s Office of Science, for providing support for meeting and specialized studies of the Group members. PAS was funded by the U.K. Department for Environment, Food and Rural Affairs under contract PECD 7/12/37. GH was also funded by NSF grant ATM-0296007. We also thank Karen King of DOE’s Pacific Northwest National Laboratory for handing the Group’s administrative matters and Jesse Kenyon for help with the manuscript.
Allen, M. R., and P. A. Stott, 2003: Estimating signal amplitudes in optimal fingerprinting, Part I: Theory. Climate Dyn., 21 , 477–491.
Allen, M. R., P. A. Stott, J. F. B. Mitchell, R. Schnur, and T. Delworth, 2000: Quantifying the uncertainty in forecasts of anthropogenic climate change. Nature, 407 , 617–620.
Allen, M. R., and Coauthors, 2004: Quantifying anthropogenic influence on recent near-surface temperature. Surv. Geophys., in press.
Anderson, T. L., R. J. Charlson, S. E. Schwartz, R. Knutti, O. Boucher, H. Rodhe, and J. Heintzenberg, 2003: Climate forcing by aerosols—A hazy picture. Science, 16 , 1103–1104.
Andronova, N. G., and M. E. Schlesinger, 2000: Causes of global temperature changes during the 19th and 20th centuries. Geophys. Res. Lett., 27 , 2137–2140.
Angell, J. K., 2000: Difference in radiosonde temperature trend for the period 1979–1988 of MSU data and the period 1959–1998 twice as long. Geophys. Res. Lett., 27 , 2177–2180.
Banks, H. T., and N. L. Bindoff, 2003: Comparison of observed temperature and salinity changes in the Indo-Pacific with results from the coupled climate model HadCM: Processes and mechanisms. J. Climate, 16 , 156–166.
Barnett, T. P., and Coauthors, 1999: Detection and attribution of recent climate change: A status report. Bull. Amer. Meteor. Soc., 80 , 2631–2659.
Barnett, T. P., D. W. Pierce, and R. Schnur, 2001: Detection of anthropogenic climate change in the world’s oceans. Science, 292 , 270–274.
Basnett, T. A., and D. E. Parker, 1997: Development of the global mean sea-level pressure data set GMSLP2. Climate Research Tech. Note 79, Hadley Centre, Met Office, Bracknell, United Kingdom, 16 pp.
Bauer, E., M. Claussen, and V. Brovkin, 2003: Assessing climate forcings of the Earth system for the past millennium. Geophys. Res. Lett., 30 .1276, doi:10.1029/GL016639.
Bengtsson, L., E. Roeckner, and M. Stendel, 1999: Why is global warming proceeding much slower than expected? J. Geophys. Res., 104 , 3865–3876.
Bertrand, C., M. F. Loutre, M. Crucifix, and A. Berger, 2002: Climate of the last millennium: A sensitivity study. Tellus, 54A , 221–244.
Braganza, K., D. J. Karoly, A. C. Hirst, P. Stott, R. J. Stouffer, and S. F. B. Tett, 2004: Simple indices of global climate variability and change: Part II: Attribution of climate change during the 20th century. Climate Dyn., 22 , 823–838.
Briffa, K. R., T. J. Osborn, F. H. Schweingruber, I. C. Harris, P. D. Jones, S. G. Shiyatov, and E. A. Vaganov, 2001: Low-frequency temperature variations from a northern tree-ring density network. J. Geophys. Res., 106 , 2929–2941.
Cabanes, C., A. Cazenave, and C. Le Provost, 2001: Sea level rise during past 40 years determined from satellite and in situ observations. Science, 294 , 840–842.
Christy, J. R., R. W. Spencer, and E. Lobl, 1998: Analysis of the merging procedure for the MSU daily temperature time series. J. Climate, 5 , 2016–2041.
Christy, J. R., R. W. Spencer, and W. D. Braswell, 2000: MSU tropospheric temperatures: Dataset construction and radiosonde comparison. J. Atmos. Oceanic Technol., 17 , 1153–1170.
Crowley, T. J., and T. S. Lowery, 2000: How warm was the medieval warm period? A comment on “Man-made versus natural climate change.”. Ambio, 29 , 51–54.
Crowley, T. J., S. K. Baum, K-Y. Kim, G. C. Hegerl, and W. T. Hyde, 2003: Modeling ocean heat content changes during the last millennium. Geophys. Res. Lett., 30 .1932, doi:10.1029/2003GL017801.
Diaz, H. F., C. K. Folland, T. Manabe, D. E. Parker, R. W. Reynolds, and S. D. Woodruff, 2002: Workshop on advances in the use of historical marine climate data. WMO Bull. 51, 4 pp.
Esper, J., E. Cook, and F. H. Schweingruber, 2002: Low-frequency signals in long tree-ring chronologies for reconstructing past temperature variability. Science, 295 , 2250–2253.
Folland, C. K., and Coauthors, 2001a: Global temperature change and its uncertainties since 1861. Geophys. Res. Lett., 28 , 2621–2624.
Folland, C. K., and Coauthors, 2001b: Observed climate variability and change. Climate Change 2001: The Scientific Basis, J. T. Houghton et al., Eds., Cambridge University Press, 99–181.
Forest, C. E., M. R. Allen, P. H. Stone, and A. P. Sokolov, 2000: Constraining uncertainties in climate models using climate change detection techniques. Geophys. Res. Lett., 27 , 569–572.
Forest, C. E., P. H. Stone, A. P. Sokolov, M. R. Allen, and M. D. Webster, 2002: Quantifying uncertainties in climate system properties with the use of recent observations. Science, 295 , 113–117.
Free, M., and J. K. Angell, 2002: Effect of volcanoes on the vertical temperature profile in radiosonde data. J. Geophys. Res., 107 .4101, doi:10.1029/2001JD001128.
Frich, P., L. V. Alexander, P. Della-Marta, B. Gleason, M. Haylock, A. M. G. Klein-Tank, and T. Peterson, 2002: Observed coherent changes in climatic extremes during the second half of the twentieth century. Climate Res., 19 , 193–212.
Fu, Q., C. M. Johanson, S. G. Warren, and D. J. Seidel, 2004: Contribution of stratospheric cooling to satellite-inferred tropospheric temperature trends. Nature, 429 , 55–58.
Fyfe, J. C., G. J. Boer, and G. M. Flato, 1999: The Arctic and Antarctic Oscillations and their projected changes under global warming. Geophys. Res. Lett., 26 , 1601–1604.
Gaffen, D. J., B. D. Santer, J. S. Boyle, J. R. Christy, N. E. Graham, and R. J. Ross, 2000: Multidecadal changes in the vertical structure of the tropical troposphere. Science, 287 , 1242–1245.
Gillett, N. P., G. C. Hegerl, M. R. Allen, and P. A. Stott, 2000: Implications of changes in the Northern Hemispheric circulation for the detection of anthropogenic climate change. Geophys. Res. Lett., 27 , 993–996.
Gillett, N. P., G. C. Hegerl, M. R. Allen, P. A. Stott, and R. Schnur, 2002a: Reconciling two approaches to the detection of anthropogenic influence on climate. J. Climate, 15 , 326–329.
Gillett, N. P., F. W. Zwiers, A. J. Weaver, G. C. Hegerl, M. R. Allen, and P. A. Stott, 2002b: Detecting anthropogenic influence with a multi-model ensemble. Geophys. Res. Lett., 29 .1970, doi:10.1029/2002GL015836.
Gillett, N. P., H. Graf, and T. Osborn, 2003a: Climate change and the NAO. The North Atlantic Oscillation: Climate Significance and Environmental Impact, J. Hurrell et al., Eds., Amer. Geophys. Union, 193–210.
Gillett, N. P., F. W. Zwiers, A. J. Weaver, and P. A. Stott, 2003b: Detection of human influence on sea level pressure. Nature, 422 , 292–294.
Gillett, N. P., A. J. Weaver, F. W. Zwiers, and M. F. Wehner, 2004: Detection of volcanic influence on global precipitation. Geophys. Res. Lett., 31 .L12217, doi:10.1029/2004GL020044.