Carbon nanomaterials possess unique physical-chemical properties and have been applied in numerous areas [1–9]. Significant commercial interest has stimulated an increase in production capacity of carbon nanomaterials, and demand is still continually increasing [10,11]. Given that the main component of carbon nanomaterials such as carbon nanotubes, graphene and fullerene is carbon, a high proportion of the Earth’s carbon has been moved into these materials. Until now, however, they have not been considered as a potentially important part of carbon cycle because they are new emerging materials. The specific issue that we are addressing is whether carbon nanomaterials will play a role in carbon cycle. Herein, we provide three pieces of scientific evidence that demonstrate their potential role in carbon cycle: The first issue is that the carbon amount in carbon nanomaterials will become very large as the production of carbon nanomaterials continuously increases. It has been reported thatthe estimated production capacity of carbon nanotubes in 2011 was >4.5 kiloton/year, which is about 10 times more than that in 2006 [3]. For graphene films and small graphene sheets, the annual production capacity in China was reported to be more than 110,000 m2 and 0.4 kiloton, respectively [5]. The estimated annual U.S. production of fullerenes was 0.002–0.080 kiloton/year [7].
