英国牛津大学Ella V. Walsh课题组取得一项新突破。他们最新的研究揭示了大洲尺度上矿物冻土反馈的温度敏感性。相关论文发表在2024年10月9日出版的《科学进展》杂志上。

据介绍，沉积岩中硫化物矿物的氧化风化作用将二氧化碳(CO₂)释放到大气中。在永久冻土带，如果该氧化风化作用随着变暖而增加，可能是其对气候变化的积极反馈，但硫化物氧化率及其温度响应在大的时空尺度上仍然未知。

研究分析了Mackenzie河盆地60年的硫酸盐浓度数据集。结果显示，气温升高2.3°C时，硫酸盐通量增加了45%，温度敏感性表明，到2100年，大陆尺度的CO₂通量可能会翻一番。最大的增加发生在具有地貌环境的集水区，这些集水区通过物理风化和热岩溶作用使岩石迅速暴露。

与风化模型的比较表明，变暖可以增加反应速率，并且矿物暴露也需要随着变暖而变化。研究结果强调，未来北极地区的变暖可能会进一步增加硫化物氧化速率，并影响区域碳循环收支。

附：英文原文

Title: Temperature sensitivity of the mineral permafrost feedback at the continental scale

Author: Ella V. Walsh, Robert G. Hilton, Suzanne E. Tank, Edwin Amos

Issue&Volume: 2024-10-09

Abstract: Oxidative weathering of sulfide minerals in sedimentary rocks releases carbon dioxide (CO₂) into the atmosphere. In permafrost zones, this could be a positive feedback on climate change if it increases with warming, yet sulfide oxidation rates and their temperature response remain unknown over large spatial and temporal scales. We analyze a 60-year sulfate concentration dataset from catchments across the Mackenzie River Basin. Sulfate fluxes increased by 45% in the mainstem with 2.3°C of warming, and the temperature sensitivity suggests that continental-scale CO₂ fluxes could double by 2100. The largest increases occur in catchments with geomorphic settings which act to rapidly expose rocks through physical weathering and thermokarst processes. Comparisons with a weathering model suggest that warming can increase reaction rates, and changes in the exposure of minerals with warming are also required. Future warming across vast Arctic landscapes could further increase sulfide oxidation rates and affect regional carbon cycle budgets.

DOI: adq4893

Source: https://www.science.org/doi/10.1126/sciadv.adq4893