Quantifying the Competing Roles of Global Warming and the Strengthened Siberian High in Modulating Cold Extremes Over China

Despite global warming, China continues to experience record‐breaking cold extremes. However, the extent to which internal atmospheric circulation variability offsets anthropogenic warming effects on cold extremes remains poorly quantified. Here, a nonstationary GEV is used to quantify the relative influences of anthropogenic warming and the Siberian High (SibH) variability on cold extremes across China during 1961–2020. A decade of anthropogenic warming, represented by a one‐decade rise in global mean surface temperature (GMST), increases the GEV location parameter and induces spatially heterogeneous scale changes, generally weakening cold extremes. In contrast, a one‐standard‐deviation strengthening of the SibH produces stronger cooling: it lowers location parameters nationwide, particularly over northwestern China, where the magnitude is about twice that associated with GMST. A strengthened SibH also enhances the scale parameter over northwestern and central China, implying higher spread and increased severity of rare cold events in these regions.