Composite surface temperature history from simultaneous inversion of borehole temperatures in western Canadian plains

Functional space inversions (FSI) of precise temperature logs from wells lo cated in low conductivity elastic sediments of the western Canadian Sedimen tary Basin show evidence of extensive, recent ground surface temperature (G ST) warming. Simultaneous inversion of the data, as well as averaging of th e individual site reconstructions, indicate that this high magnitude of GST warming exceeds over two times that of globally averaged GST's [Science 28 2 (1998) 279] and is significantly higher than that of surface temperature histories based on instrumental records and tree ring reconstruction in nor thern and western Canada [Holocene 7 (1997) 375; Science 278 (1997) 1251; C lim. Res. 12 (1999) 39]. (C) 2001 Elsevier Science B.V. All rights reserved .