Institute of Carbon Cycles, Helmholtz-Zentrum Hereon, Geesthacht, Germany.
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany.
Nat Commun. 2023 Mar 24;14(1):1648. doi: 10.1038/s41467-023-37165-w.
Alkalinity generation from rock weathering modulates Earth's climate at geological time scales. Although lithology is thought to dominantly control alkalinity generation globally, the role of other first-order controls appears elusive. Particularly challenging remains the discrimination of climatic and erosional influences. Based on global observations, here we uncover the role of erosion rate in governing riverine alkalinity, accompanied by areal proportion of carbonate, mean annual temperature, catchment area, and soil regolith thickness. We show that the weathering flux to the ocean will be significantly altered by climate warming as early as 2100, by up to 68% depending on the environmental conditions, constituting a sudden feedback of ocean CO sequestration to climate. Interestingly, warming under a low-emissions scenario will reduce terrestrial alkalinity flux from mid-latitudes (-1.6 t(bicarbonate) a km) until the end of the century, resulting in a reduction in CO sequestration, but an increase (+0.5 t(bicarbonate) a km) from mid-latitudes is likely under a high-emissions scenario, yielding an additional CO sink.
岩石风化产生的碱度调节着地球在地质时间尺度上的气候。尽管岩性被认为是全球控制碱度产生的主要因素，但其他一级控制因素的作用似乎难以捉摸。特别具有挑战性的仍然是区分气候和侵蚀的影响。基于全球观测，我们在这里揭示了侵蚀率在控制河流碱度方面的作用，同时还考虑了碳酸盐的面积比例、年平均温度、流域面积和土壤表土厚度。我们表明，到 2100 年，气候变暖将极大地改变海洋风化通量，具体取决于环境条件，最大可达 68%，这构成了海洋 CO 封存对气候的突然反馈。有趣的是，在低排放情景下，中纬度地区的陆地碱度通量将减少（-1.6 t(碳酸氢盐) a km），直到本世纪末，从而减少 CO 封存，但在高排放情景下，中纬度地区的 CO 封存可能会增加（+0.5 t(碳酸氢盐) a km），从而增加 CO 汇。
