Comparison of carbon sequestration capacity between carbonate weathering and forests: The necessity to change traditional ideas and methods of study of carbon sinks

At present, researches on the modern global carbon cycle focuses mainly on carbon sinks caused by the oceans and the terrestrial soils and vegetation. In addition, chemical weathering of Ca-silicate rocks is considered to have the potential in controlling long-term climate change by providing feedback interactions with atmospheric CO2 drawdown by means of the precipitation of carbonate. In contrast, carbonate weathering itself has not been given equivalent attention although it is much more rapid than silicate weathering and more sensitive to global changes (especially climate and CO2 change).Further, biological and human activities also significantly influence carbonate weathering. Thus, the contribution of carbonate weathering to the atmospheric CO2 sink should be re-evaluated. Latest studies show that the carbon sink through the combined action of carbonate dissolution, the global water cycle, and photosynthetic uptake of dissolved inorganic carbon by aquatic organisms (i.e., by carbonate weathering via the water-rock-gas-organism interaction) is far greater than previous estimates that have only considered the transport of dissolved inorganic carbon by rivers, and have a similar magnitude to that of the terrestrial carbon sink in global forests. Therefore, changes in traditional ideas and methods of carbon sink study are necessary, and may provide a way to solve the so called global “missing carbon sink “problem.