古气候的启示

Implications of Paleoclimate

回顾了近20～30年古气候的研究进展,包括下列问题:雪球和热力极大期、冰期-间冰期旋回、古季风、D/O循环和H事件、全新世季风、全新世气候突变、气候变化与古文明、近2000年的气候。研究表明,第四纪前的气候变化中CO_2起着重要的作用,但是在冰期-间冰期旋回中CO_2变化落后于温度变化。这说明虽然影响机制不同,但是温室气体和气候间有着密切的相互作用这一点则是可以肯定的。地球目前处于间冰期,面临着冰期来临的威胁。人类活动造成的气候变暖有可能推迟下一次冰期的到来。21世纪全球变暖仍将继续,人们可能做的、也是必须要做的,是尽可能地降低变暖的速率,以及可能达到的变暖峰值。

Studies on the paleoclimate during the last 20-30 years are reviewed.The following hot topics are discussed：snowball Earth and Paleocene-Eocene thermal maximum（PETM）,glacial-interglacial cycles, paleo-monsoon,D/O cycles and H events,Holocene monsoon,abrupt climate change in the Holocene, climate change and associated ancient civilization,and the last 2 ka climate.It is indicated that,the snowball Earth and PETM were caused by the depletion and explosive increasing of CO_2 in the atmosphere respectively.However,the change of temperature was preceding that of greenhouse gases in glacialinterglacial cycle,as found in the ice cores in the Antarctica.It is also shown that the changes of temperatures and greenhouse gases were highly correlated before the Quaternary,but changed after that,which might be linked to a differed mechanism.Enhancement of greenhouse effect in the present will,probably to some extent,delay the onset of the next glacial period.In any case,anthropogenic effect on the climate will definitely continue in the 21st century even we turn to reduce the emission of greenhouse gases in some ways.The global warming will remain as a critical issue,which we have to face in near future.