Revisiting ocean carbon sequestration by direct injection: a global carbon budget perspective
Revisiting ocean carbon sequestration by direct injection: a global carbon budget perspective
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重新审视直接注入海洋碳封存：全球碳预算视角
DOI：
10.5194/esd-7-797-2016
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
A. Oschlies
中科院分区：
文献类型：
--
作者：
Fabian Reith;D. Keller;A. Oschlies
在这项研究中，我们超越了先前研究的海洋二氧化碳注入对大气和海洋水库的影响，还考虑了大气和陆地生物圈之间的碳循环和气候反馈。考虑这些额外的反馈是重要的，因为从陆地生物圈到大气的回流可以进一步抵消定向减排的影响。为了量化这些动态，我们使用一个中等复杂性的地球系统模型来模拟二氧化碳直接注入深海，作为在高二氧化碳排放情景下减少排放的一种手段。在三组不同注入深度的实验中，我们模拟了总计70 GTC的100年注入周期，并在另一个900年跟踪全球碳循环动态。在附加参数摄动运行中，我们将默认的陆地光合作用二氧化碳施肥参数化改变了±50 %，以测试这种不确定的碳循环反馈对通过直接注入二氧化碳而实现的目标大气碳减排的敏感性。模拟的海水化学变化和海洋碳储存效率与以前的研究相似。正如预期的那样，到注入期结束时，由于陆地和海洋水库的碳循环反馈和回流，避免的排放量比目标的70 GTC低16-30 %。与未扰动的喷射运行相比，参数扰动模拟中的目标排放在喷射周期结束时多了约0.2%和2 %，在模拟结束时减少了约9 %至1 %。
一个意想不到的特点是，该模型对南大洋深水形成的内部可变性的影响，在一些模型运行中，相对于不注入的对照运行，在注入终止后导致额外的海洋碳吸收，因此大气中的二氧化碳和气候略有不同。一个内部气候变率很低的模型的这些结果表明，在内部变率要大得多的真实气候系统中，碳通量的分配和注入的二氧化碳的计算可能是非常具有挑战性的。
In this study we look beyond the previously studied effects of oceanic CO2 injections on atmospheric and oceanic reservoirs and also account for carbon cycle and climate feedbacks between the atmosphere and the terrestrial biosphere. Considering these additional feedbacks is important since backfluxes from the terrestrial biosphere to the atmosphere in response to reducing atmospheric CO2 can further offset the targeted reduction. To quantify these dynamics we use an Earth system model of intermediate complexity to simulate direct injection of CO2 into the deep ocean as a means of emissions mitigation during a high CO2 emission scenario. In three sets of experiments with different injection depths, we simulate a 100-year injection period of a total of 70 GtC and follow global carbon cycle dynamics over another 900 years. In additional parameter perturbation runs, we varied the default terrestrial photosynthesis CO2 fertilization parameterization by ±50 % in order to test the sensitivity of this uncertain carbon cycle feedback to the targeted atmospheric carbon reduction through direct CO2 injections. Simulated seawater chemistry changes and marine carbon storage effectiveness are similar to previous studies. As expected, by the end of the injection period avoided emissions fall short of the targeted 70 GtC by 16–30 % as a result of carbon cycle feedbacks and backfluxes in both land and ocean reservoirs. The target emissions reduction in the parameter perturbation simulations is about 0.2 and 2 % more at the end of the injection period and about 9 % less to 1 % more at the end of the simulations when compared to the unperturbed injection runs.
An unexpected feature is the effect of the model's internal variability of deep-water formation in the Southern Ocean, which, in some model runs, causes additional oceanic carbon uptake after injection termination relative to a control run without injection and therefore with slightly different atmospheric CO2 and climate. These results of a model that has very low internal climate variability illustrate that the attribution of carbon fluxes and accounting for injected CO2 may be very challenging in the real climate system with its much larger internal variability.
影响因子：
16.6
作者：
Keller, David P.;Feng, Ellias Y.;Oschlies, Andreas
通讯作者：
Oschlies, Andreas
影响因子：
4.3
作者：
Eby, M.;Weaver, A. J.;Zhao, F.
通讯作者：
Zhao, F.