[1] Univ Wales, Sch Archaeol Hist & Anthropol, Lampeter, Dyfed, Wales
[2] Aberystwyth Univ, Inst Geog & Earth Sci, Aberystwyth, Dyfed, Wales
[3] Univ Colorado, Dept Atmospher & Ocean Sci, Boulder, CO 80309 USA
[4] Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA
[5] Lund Univ, Dept Geol, Lund, Sweden
[6] Univ New Brunswick, Dept Biol, Fredericton, NB E3B 6E1, Canada
[7] Nat Resources Canada, Ottawa, ON, Canada
[8] Univ Durham, Dept Geog, Durham, England
[9] Univ London, Dept Geog, Egham, Surrey, England
[10] Victoria Univ Wellington, Sch Geog Environm & Earth Sci, Wellington, New Zealand
[11] Univ Copenhagen, Niels Bohr Inst, Ctr Ice & Climate, DK-2100 Copenhagen, Denmark
[12] Yale Univ, Sch Forestry & Environm Studies, New Haven, CT 06511 USA