Contrasting vegetation response to compound temperature and moisture extremes across Northern Hemisphere

The increasing frequency of compound extreme events (CEs) amidst climate change presents significant challenges to ecosystems, resulting in dramatic declines in vegetation greening and productivity. While most research has focused predominantly on individual extreme events like droughts, heatwaves, or compound hot-drought (CHD) events, other CEs, including compound hot-wet (CHW), cold-drought (CCD), and cold-wet (CCW) events, remain relatively understudied. Therefore, this study examines the potential impacts of four CEs on vegetation anomalies (SkNDVI<0) during the growing season from 1982 to 2022 across the Northern Hemisphere (0°-90°N), utilizing a vine copula-based conditional probability approach. The findings uncover distinct spatial patterns in vegetation's response to various CEs. Notably, both CHD and CCD exerted considerable influence on vegetation in regions like western United States and Ethiopia. Whereas vegetation in regions such as Cananda, northeast Europe and central Eurasia exhibited heightened vulnerability to CCD and CCW. Furthermore, the likelihood of vegetation being impacted by various CEs varied across diverse climate zones and biomes. Grasslands and Shrublands in arid and semi-arid regions were affected by both CHD and CCD events and Forests in humid and semi-humid regions demonstrated greater responsiveness to CCD and CCW. These discoveries enhance our comprehension of the multifaceted impacts of CEs on ecosystems and offer valuable insights for devising strategies aimed at mitigating their detrimental effects.