Most global climate models project a considerable stratospheric moistening during global warming. It is important to quantify how significantly the increase of stratospheric humidity affects the radiation budget and contributes to the surface warming. Here, we conduct a mechanism denial experiment to investigate the warming effect of the stratospheric water vapor (SWV) using a global climate model. By locking the SWV in a quadrupling CO₂ experiment, we find that the surface warming effect of SWV is not as significant as previously thought, increasing the global mean surface warming by about 2%. This is due to compensating changes in other feedback, especially those of tropospheric temperature and cloud, affected by SWV.

中文翻译：

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通过锁定实验揭示平流层水汽反馈

大多数全球气候模型预测，在全球变暖期间，平流层将出现相当大的湿润。重要的是要量化平流层湿度的增加如何显着影响辐射预算并促进表面变暖。在这里，我们进行了一个机制否认实验，以使用全球气候模型研究平流层水蒸气（SWV）的变暖效应。通过将SWV锁定在四倍的CO ₂实验中，我们发现SWV的表面变暖效果不像以前认为的那么重要，从而使整体平均表面变暖增加了大约2％。这是由于补偿了受SWV影响的其他反馈的变化，尤其是对流层温度和云的变化。