QICS Paper: Modelling Large-Scale CO2 Leakages in the North Sea

A three dimensional hydrodynamic model with a coupled carbonate speciation sub-model is used to simulate large additions of CO2 into the North Sea, representing leakages at potential carbon sequestration sites. A range of leakage scenarios are conducted at two distinct release sites, allowing an analysis of the seasonal, inter-annual and spatial variability of impacts to the marine ecosystem. Seasonally stratified regions are shown to be more vulnerable to CO2 release during the summer as the added CO2 remains trapped beneath the thermocline, preventing outgasing to the atmosphere. On average, CO2 injected into the northern North Sea is shown to reside within the water column twice as long as an equivalent addition in the southern North Sea before reaching the atmosphere. Short-term leakages of 5000 tonnes CO2 over a single day result in substantial acidification at the release sites (up to -1.92 pH units), with significant perturbations (greater than 0.1 pH units) generally confined to a 10 km radius. Long-term CO2 leakages sustained for a year may result in extensive plumes of acidified seawater, carried by major advective pathways. Whilst such scenarios could be harmful to marine biota over confined spatial scales, continued unmitigated CO2 emissions from fossil fuels are predicted to result in greater and more long-lived perturbations to the carbonate system over the next few decades. This is a publication in QICS Special Issue - International Journal of Greenhouse Gas Control, Jack J.C. Phelps et. al. Doi:10.1016/j.ijggc.2014.10.013.

采用一个耦合碳酸盐物种子模型的三维水动力学模型，模拟了大量二氧化碳注入北海的过程，该模拟反映了在潜在的碳封存地点的泄漏情况。在两个不同的释放地点开展了多种泄漏情景的实验，以分析对海洋生态系统的影响在季节性、年度和空间尺度上的变化。研究表明，季节性分层区域在夏季对二氧化碳释放更为脆弱，因为额外的二氧化碳被困在温跃层之下，阻止了向大气中的逸出。平均而言，注入北海北部的二氧化碳在达到大气之前，在水柱中停留的时间是南部北海中同等增加量的两倍。在单日内5000吨二氧化碳的短期泄漏会导致释放地点出现显著的酸化（pH值下降高达1.92单位），而pH值变化超过0.1单位的显著扰动通常局限于10公里半径范围内。长期维持一年的二氧化碳泄漏可能导致广泛的酸化海水羽流，这些羽流由主要的大气输送途径携带。虽然在这些有限的区域尺度上，此类情景可能对海洋生物造成危害，但持续未受控制的化石燃料二氧化碳排放预计将在未来几十年内导致碳酸盐系统出现更大、更持久的扰动。这是一篇发表在QICS特别问题——国际温室气体控制杂志上的论文，作者为Jack J.C. Phelps等人，DOI：10.1016/j.ijggc.2014.10.013。