Evolution of the Global Carbon Cycle and Climate Regulation on Earth
Evolution of the Global Carbon Cycle and Climate Regulation on Earth
复制标题
DOI：
10.1029/2018gb006061
复制
发表时间：
2020-02-01
影响因子：
5.2
通讯作者：
Kump, L. R.
中科院分区：
文献类型：
--
作者：
Isson, T. T.;Planavsky, N. J.;Kump, L. R.
地球气候系统中稳定反馈的存在通常被认为是液态水和生命持续存在的必要条件。在地球的历史进程中，地球的大气成分似乎已经适应了太阳亮度的逐渐增加，导致表面温度持续适宜居住。除了有限的例外，地球系统已被观察到从脉冲气候扰动中迅速恢复。在耦合的全球碳-硅循环中，通过负反馈对二氧化碳（CO2）进行调节，通常被视为导致地球气候稳定的主要过程。在这里，我们回顾了长期全球碳循环预算，以及调节地球气候系统的过程如何随着时间的推移而演变。具体来说，我们关注的是碳源和碳汇的变化在推动大气pCO(2)长期变化中所起的相对作用。我们认为海洋过程是典型硅酸盐风化反馈的重要组成部分，并且在pCO(2)调节中发挥的作用比传统想象的要重要得多。值得注意的是，地球化学证据表明，海洋沉积物的风化作用和离轴玄武岩蚀变是主要的碳汇。然而，在地球早期的历史中，当海洋中溶解的硅（Si）、铁（Fe）和镁（Mg）含量较高时，这个碳汇可能被抑制了，相反，它可能通过逆风在海洋-大气系统中促进了更广泛的碳循环——这反过来又提高了海洋-大气中的二氧化碳水平。
The existence of stabilizing feedbacks within Earth's climate system is generally thought to be necessary for the persistence of liquid water and life. Over the course of Earth's history, Earth's atmospheric composition appears to have adjusted to the gradual increase in solar luminosity, resulting in persistently habitable surface temperatures. With limited exceptions, the Earth system has been observed to recover rapidly from pulsed climatic perturbations. Carbon dioxide (CO2) regulation via negative feedbacks within the coupled global carbon-silica cycles are classically viewed as the main processes giving rise to climate stability on Earth. Here we review the long-term global carbon cycle budget, and how the processes modulating Earth's climate system have evolved over time. Specifically, we focus on the relative roles that shifts in carbon sources and sinks have played in driving long-term changes in atmospheric pCO(2). We make the case that marine processes are an important component of the canonical silicate weathering feedback, and have played a much more important role in pCO(2) regulation than traditionally imagined. Notably, geochemical evidence indicate that the weathering of marine sediments and off-axis basalt alteration act as major carbon sinks. However, this sink was potentially dampened during Earth's early history when oceans had higher levels of dissolved silicon (Si), iron (Fe), and magnesium (Mg), and instead likely fostered more extensive carbon recycling within the ocean-atmosphere system via reverse weathering-that in turn acted to elevate ocean-atmosphere CO2 levels.