More droughts and more severe droughts

Most regions on Earth are warmer at present than in past decades and centuries, and many regions are experiencing a drying trend as a result of less rain and snow, more intermittent precipitation (less frequent rain and snow but more intense events) and/or higher rates of evaporation. More climate extremes, including prolonged droughts and heatwaves, have recently occurred across the globe. Moreover, human activity has been shown to make naturally-occurring droughts worse. A further increase in the coverage, duration, and occurrence of extreme droughts is projected for many regions during the twenty-first century. Drying is expected even at high elevations and in cold regions because of warming-induced earlier snowmelt (adapted from the article).

Featured article:

*Grünzweig, J. M., de Boeck, H. J., Rey, A., Santos, M. J., Adam, O., Bahn, M., … & Yakir, D. (2022). Dryland mechanisms could widely control ecosystem functioning in a drier and warmer world. Nature Ecology & Evolution. [Cited by]

“Responses of terrestrial ecosystems to climate change have been explored in many regions worldwide. While continued drying and warming may alter process rates and deteriorate the state and performance of ecosystems, it could also lead to more fundamental changes in the mechanisms governing ecosystem functioning. Here we argue that climate change will induce unprecedented shifts in these mechanisms in historically wetter climatic zones, towards mechanisms currently prevalent in dry regions, which we refer to as ‘dryland mechanisms’. We discuss 12 dryland mechanisms affecting multiple processes of ecosystem functioning, including vegetation development, water flow, energy budget, carbon and nutrient cycling, plant production and organic matter decomposition. We then examine mostly rare examples of the operation of these mechanisms in non-dryland regions where they have been considered irrelevant at present. Current and future climate trends could force microclimatic conditions across thresholds and lead to the emergence of dryland mechanisms and their increasing control over ecosystem functioning in many biomes on Earth.”

Questions? Please let me know (engelk@grinnell.edu).

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