To monitor the success of carbon dioxide removal (CDR) or solar radiation management (SRM) that offset anthropogenic climate change, the forced response to any external forcing is required to be detectable against internal variability. Thus far, only the detectability of SRM has been examined using both a stationary and nonstationary detection and attribution method. Here, the spatiotemporal detectability of the forced response to artificial ocean alkalinization (AOA) and stratospheric aerosol injection (SAI) as exemplary methods for CDR and SRM, respectively, is compared in Max Planck Institute Earth System Model (MPI‐ESM) experiments using regularized optimal fingerprinting and single‐model estimates of internal variability, while working under a stationary or nonstationary null hypothesis. Although both experiments are forced by emissions according to the Representative Concentration Pathway 8.5 (RCP8.5) and target the climate of the RCP4.5 scenario using AOA or SAI, detection timescales reflect the fundamentally different forcing agents. Moreover, detectability timescales are sensitive to the choice of null hypothesis. Globally, changes in the CO₂ system in seawater are detected earlier than the response in temperature to AOA but later in the case of SAI. Locally, the detection time scales depend on the physical, chemical, and radiative impacts of CDR and SRM forcing on the climate system, as well as patterns of internal variability, which is highlighted for oceanic heat and carbon storage.

中文翻译：

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MPI-ESM中人工海洋碱化和平流层气溶胶注入的可检测性

为了监控抵消人为气候变化的二氧化碳清除（CDR）或太阳辐射管理（SRM）的成功，需要检测到对任何外部强迫的强迫响应，以应对内部变化。到目前为止，仅使用固定和非固定检测和归因方法都检查了SRM的可检测性。在这里，分别在Max Planck Institute地球系统模型（MPI-ESM）实验中使用正则化方法比较了对人工海洋碱化（AOA）和平流层气溶胶注入（SAI）作为CDR和SRM的示例性方法的强迫响应的时空可检测性在固定或非平稳原假设下工作时，最佳指纹图谱和内部可变性的单模型估计。尽管两个实验都是根据“代表性浓度途径8.5（RCP8.5）”由排放强迫的，并且使用AOA或SAI锁定RCP4.5情景的气候，但检测时间尺度反映了根本不同的强迫因素。此外，可检测时间尺度对零假设的选择很敏感。在全球范围内，CO的变化在海水中_2个系统的检测早于温度对AOA的响应，但在SAI情况下则较晚。在本地，检测时间尺度取决于CDR和SRM强迫对气候系统的物理，化学和辐射影响，以及内部可变性的模式，这对于海洋热量和碳储量尤为突出。