How temperature-dependent silicate weathering acts as Earth's geological thermostat

• 成果类型: Article
• 署名作者: Brantley, S. L.; Shaughnessy, Andrew; Lebedeva, Marina I.; Balashov, Victor N.
• 署名单位: Pennsylvania Commonwealth System of Higher Education (PCSHE); Pennsylvania State University; Pennsylvania State University - University Park; Pennsylvania Commonwealth System of Higher Education (PCSHE); Pennsylvania State University; Pennsylvania State University - University Park
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-13539
• DOI: 10.1126/science.add2922
• 发表日期: 2023-01-27
• 页码: 382-389
• 关键词: global temperature; atmospheric co2; carbon-cycle; ab-initio; climate; rates; geochemistry; dissolution; feedback; erosion

摘要

Earth's climate may be stabilized over millennia by solubilization of atmospheric carbon dioxide (CO2) 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 similar 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 CO2 drawdown by natural or enhanced weathering.