The global decline in the sensitivity of vegetation productivity to precipitation from 2001-2018

<p><span>The sensitivity of vegetation productivity to precipitation (<em>S_ppt</em>) is a key metric for understanding the variations in vegetation productivity under changing precipitation and predicting future changes in ecosystem functions. However, a comprehensive assessment of </span><span><em>S_ppt</em></span><span> over all the global land is lacking. Here, we investigated spatial patterns and temporal changes of </span><span><em>S_ppt</em></span><span> across the global land from 2001 to 2018 with multiple streams of satellite observations. We found consistent spatial patterns of </span><span><em>S_ppt</em></span><span> with different satellite products: Sppt was highest in dry regions while low in humid regions. Grassland and shrubland showed the highest </span><span><em>S_ppt</em></span><span>, and evergreen needle-leaf forest and wetland showed the lowest. Temporally, </span><span><em>S_ppt</em></span><span> showed a generally declining trend over the past two decades (<em>p</em> &lt; 0.05), yet with clear spatial heterogeneities. The decline in </span><span><em>S_ppt</em></span><span> was especially noticeable in North America and Europe, likely due to the increase in precipitation. In central Russia and Australia, however, </span><span><em>S_ppt</em></span><span> showed an increasing trend. Biome-wise, most ecosystem types exhibited significant decreases in </span><span><em>S_ppt</em></span><span>, while grassland, evergreen broadleaf forest, and mixed forest showed slight increases or non-significant changes in </span><span><em>S_ppt</em></span><span>. Our finding of the overall decline in </span><span><em>S_ppt</em></span><span> implies a potential stabilization mechanism for ecosystem productivity under climate change. However, the revealed </span><span><em>S_ppt</em></span><span> increase for some regions and ecosystem types, in particular global grasslands, suggests that grasslands might be increasingly vulnerable to climatic variability with continuing global climate change.</span></p>