Climate 400,000 years ago, a key to the future?

摘要: To better understand our present-day climate and its future, paleoclimatologists are searching the past for analogues or even warmer periods than present interglacial. For long, Eemian interglacial, which happened some 125,000 years ago during marine isotopic stage 5e was considered a good candidate [Kukla et al., 1972; Kellogg, 1977]. The validity of such an assumption questioned in terms data 1997] mechanisms producing warm [Berger, 1989], mainly relation to future increase concentration greenhouse gases [Mitchell, 1990] seasonal cycle insolation [Crowley, 1990]. If any, interglacial centered 400,000 (marine 11 - MIS 11) may fit [Burckle, 1993], because Earth's astronomical parameters inferred latitudinal distributions at top atmosphere (the Milankovitch effect) will be more similar what it then as consequence 400-kyr eccentricity 1978; Berger 1998a]. Simulations using LLN model confirm that [Droxler Burckle, 1999] lead understanding [Loutre Berger, 2000a]. Moreover we also low amplitude change well Holocene next tens thousands makes sensitive atmospheric CO 2 times higher change. Therefore human induced gas might affect drastically past.