晚古生代冰消期二氧化碳驱动的气候与植被不稳定性

CO2-forced climate and vegetation instability during Late Paleozoic deglaciation.

作者信息

Montañez Isabel P, Tabor Neil J, Niemeier Deb, Dimichele William A, Frank Tracy D, Fielding Christopher R, Isbell John L, Birgenheier Lauren P, Rygel Michael C

机构信息

Department of Geology, University of California, Davis, CA 95616, USA.

出版信息

Science. 2007 Jan 5;315(5808):87-91. doi: 10.1126/science.1134207.

DOI:10.1126/science.1134207

PMID:17204648

Abstract

The late Paleozoic deglaciation is the vegetated Earth's only recorded icehouse-to-greenhouse transition, yet the climate dynamics remain enigmatic. By using the stable isotopic compositions of soil-formed minerals, fossil-plant matter, and shallow-water brachiopods, we estimated atmospheric partial pressure of carbon dioxide (pCO2) and tropical marine surface temperatures during this climate transition. Comparison to southern Gondwanan glacial records documents covariance between inferred shifts in pCO2, temperature, and ice volume consistent with greenhouse gas forcing of climate. Major restructuring of paleotropical flora in western Euramerica occurred in step with climate and pCO2 shifts, illustrating the biotic impact associated with past CO2-forced turnover to a permanent ice-free world.

摘要

晚古生代的冰消作用是有植被覆盖的地球唯一一次有记录的从冰室状态到温室状态的转变，但其气候动态仍不明朗。通过利用土壤形成矿物、化石植物物质和浅水腕足动物的稳定同位素组成，我们估算了这一气候转变期间的大气二氧化碳分压（pCO2）和热带海洋表面温度。与冈瓦纳大陆南部冰川记录的对比表明，推断出的pCO2、温度和冰量变化之间存在协变关系，这与温室气体对气候的强迫作用一致。欧美大陆西部古热带植物群的重大重组与气候和pCO2的变化同步发生，说明了过去二氧化碳强迫转变为永久无冰世界所带来的生物影响。