Earth and Environmental Systems Institute, Pennsylvania State University, University Park, PA, USA.
Department of Geosciences, Pennsylvania State University, University Park, PA, USA.
Science. 2023 Jan 27;379(6630):382-389. doi: 10.1126/science.add2922. Epub 2023 Jan 26.
Earth's climate may be stabilized over millennia by solubilization of atmospheric carbon dioxide (CO) as minerals weather, but the temperature sensitivity of this thermostat is poorly understood. We discovered that the temperature dependence of weathering expressed as an activation energy increases from laboratory to watershed as transport, clay precipitation, disaggregation, and fracturing increasingly couple to dissolution. A simple upscaling to the global system indicates that the temperature dependence decreases to ~22 kilojoules per mole because (i) the lack of runoff limits weathering and retains base metal cations on half the land surface and (ii) other landscapes are regolith-shielded and show little weathering response to temperature. By comparing weathering from laboratory to globe, we reconcile some aspects of kinetic and thermodynamic controls on CO drawdown by natural or enhanced weathering.
地球的气候可能通过将大气二氧化碳（CO）溶解为矿物质而在数千年内得到稳定，但这种恒温器的温度敏感性还不太清楚。我们发现，风化的温度依赖性表现为活化能，随着运输、粘土沉淀、解团聚和断裂的不断耦合，从实验室到流域逐渐增加。简单的全球系统放大表明，温度依赖性降低到约 22 千焦/摩尔，因为（i）缺乏径流限制了风化作用，并将基础金属阳离子保留在一半的陆地表面，（ii）其他景观受到风化层的保护，对温度的风化反应很小。通过将实验室和全球的风化作用进行比较，我们调和了自然或增强风化作用对 CO 消耗的动力学和热力学控制的某些方面。
