The large-scale moistening of the atmosphere in response to increasing greenhouse gases amplifies the existing patterns of precipitation minus evaporation (P − E), which, in turn, amplifies the spatial contrast in sea surface salinity. Here, by performing a series of transient CO₂ doubling experiments, we demonstrate that surface salinification driven by the amplified dry conditions (P − E < 0), primarily in the subtropical ocean, accelerates ocean heat uptake. The salinification also drives the sequestration of upper-level heat into the deeper ocean, reducing the thermal stratification and increasing the heat uptake through positive feedback. The change in Atlantic Meridional Overturning Circulation due to salinification has a secondary role in heat uptake. Consistent with the heat uptake changes, the transient climate response would increase by approximately 0.4 K without this process. Observed multidecadal changes in subsurface temperature and salinity resemble those simulated, indicating that anthropogenically forced changes in salinity are probably enhancing ocean heat uptake.

温室气体的增加导致大气大规模湿润，放大了现有的降水减去蒸发量（ P - E ）的模式，这反过来又放大了海面盐度的空间对比。在这里，通过进行一系列瞬态CO ₂倍增实验，我们证明了由放大的干燥条件（ P − E < 0）驱动的表面盐化（主要在亚热带海洋）加速了海洋热量的吸收。盐化还推动将上层热量封存在更深的海洋中，减少热分层并通过正反馈增加热量吸收。由于盐化引起的大西洋经向翻转环流的变化在吸热方面具有次要作用。与吸热量的变化一致，如果没有这个过程，瞬态气候响应将增加约 0.4 K。观察到的地下温度和盐度的数十年变化与模拟的变化相似，表明人为强制的盐度变化可能正在增强海洋热量的吸收。