Patterns and mechanisms of early Pliocene warmth
Patterns and mechanisms of early Pliocene warmth
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DOI：
10.1038/nature12003
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发表时间：
2013-04-04
期刊：
影响因子：
64.8
通讯作者：
Ravelo, A. C.
中科院分区：
文献类型：
--
作者：
Fedorov, A. V.;Brierley, C. M.;Ravelo, A. C.
大约500万到400万年前，在上新世早期，地球上有一个温暖、温和的气候。随后的逐渐冷却导致了现代温度模式的建立，这可能是对大气二氧化碳浓度下降的反应，大约为百万分之100，接近工业化前的数值。本文综合已有的海表面温度的地球化学替代记录表明，与今天相比，上新世早期气候的经向和纬向温度梯度显著降低，而最高海洋温度相似。使用地球系统模型，我们表明，目前提出的解释上新世变暖的机制中，没有一种能够同时再现这三个关键特征。我们认为，目前模型中低估的几个动力反馈的组合，如与海洋混合和云反照率有关的反馈，可能是造成这些气候条件的原因。
About five to four million years ago, in the early Pliocene epoch, Earth had a warm, temperate climate. The gradual cooling that followed led to the establishment of modern temperature patterns, possibly in response to a decrease in atmospheric CO2 concentration, of the order of 100 parts per million, towards preindustrial values. Here we synthesize the available geochemical proxy records of sea surface temperature and show that, compared with that of today, the early Pliocene climate had substantially lower meridional and zonal temperature gradients but similar maximum ocean temperatures. Using an Earth system model, we show that none of the mechanisms currently proposed to explain Pliocene warmth can simultaneously reproduce all three crucial features. We suggest that a combination of several dynamical feedbacks underestimated in the models at present, such as those related to ocean mixing and cloud albedo, may have been responsible for these climate conditions.