岩石风化碳汇研究进展：基于IPCC第五次气候变化评估报告的分析

Some Opinions on Rock-Weathering-Related Carbon Sinks from the IPCC Fifth Assessment Report

岩石风化碳汇特别是碳酸盐岩风化碳汇积极参与了全球碳循环过程。最新的IPCC第五次气候变化评估报告（AR5）指出全球岩石风化碳汇约为0．4PgC／a，占不平衡碳通量的1／2～1／3，并改进和区分了岩石风化碳汇的时间尺度，将硅酸盐岩风化碳汇时间尺度视为104～106年，碳酸盐岩风化碳汇时间尺度视为103～104年。AR5报告将岩石风化碳汇列为CO2移除的4种方法之一，其碳酸盐岩风化碳汇时间尺度属于百年至千年级。虽然AR5报告提出了前述新认识，但仍认为岩石风化碳汇速率太慢，未纳入全球碳收支核算。结合近年来的研究进展，讨论了AR5报告目前对岩石风化碳汇在通量、时间尺度和风化碳汇效应等方面认识的不足，提出了加强岩石风化碳汇速率、稳定性、影响因素和尺度转换方面的研究建议，以期进一步加强岩石风化碳汇研究工作，为平衡全球碳收支做出科学贡献。

Many recent researches show that rock-weathering-related carbon sink, especially carbonate-weath- ering-related carbon sink, actively takes part in the modern global carbon cycle, which might greatly contribute to balancing global carbon budget. Some new opinions on flux, time scale and effect of rock-weathering-related carbon sink were released in IPCC fifth Assessment Report （ AR5 ）. The flux of global rock-weathering-related carbon sink is about 0.4 Pg C/a in AR5 report, which accounts for about 1/2 - 1/3 of unbalanced global carbon budget. New time scale of global rock-weathering-related carbon sink was released. Time scale of silicate-weathering-related car- bon sink is 104 - 106 year, while carbonate-weathering-related carbon sink （karst processes） is 103 - 104 year. A highlight is that rock-weathering-related carbon sink is listed as one of four carbon dioxide removal methods in AR5 report, whose time scale is 102 - 103 year. Although AR5 report released these new opinions, it is still thought that the rate of global rock-weathering-related carbon sink is currently too small to offset the rate at which fossil fuel CO2 is being emitted. According to many researches in the field of rock weathering science in the past decades, this re- view discussed the shortage in carbon flux, time scale and effect of rock-weathering-related carbon sink in AR5 re- port. Many recent researches indicated that the carbon sink originated from carbonate rock weathering was a fast and sensitive geochemical process, which showed multiple time scales （diel, seasonal, annual or storm event）. A new model based on HzO-carbonate-CO2-aquatic phototroph interaction was established, which coupled geological, land surface water, and submerged phototroph carbon cycle process. The global carbon sink from carbonate rock weathering in new model is 0. 477 Pg C/a,whieh accounts for about 39% - 59% of unbalanced global carbon budg- et. Some key scientific issues on rate, stability, controlling meehanisms and scaling of rock-weathering-related car- bon sink should be vitally concerned in the future, which could greatly contribute to balancing the global carbon budget.