Carbon footprint and predicting the impact of climate change on carbon sequestration ecosystem services of organic rice farming and conventional rice farming: A case study in Phichit province, Thailand

Organic rice farming is a sustainable rice cultivation system that eliminates chemical inputs and has the potential to reduce environmental impacts. This study aims to: 1) evaluate and compare the carbon footprint intensity and the value of carbon sequestration ecosystem services (VCSES) between organic rice farming (OF) and conventional rice farming (CF) and 2) estimate the impact of climate change on soil organic carbon (SOC), rice yield, and VCSES of two farming types in Phichit province, Thailand. The results showed that the carbon footprint intensity in OF and CF were significantly different with -0.13 and 0.82 kg CO(2)eq kg(-1) rice yield, respectively. The differences in SOC stocks (Delta SOCS) were more significant in OF with the increase of 1107.6 kg C ha(-1) year(-1) (4061.2 kg CO(2)eq ha(-1) year(-1)), while the Delta SOCS value in CF was 625 kg C ha(-1) year(-1) (2291.7 kg CO(2)eq ha(-1) year(-1)). The VCSES in OF (541,196 US$ ha(-1) year(-1)) was nearly two times higher than in CF (305,388 US$ ha(-1) year(-1)). Under future climate change, rice yields of both farming types are expected to increase under Representative Concentration Pathway (RCP) 2.6, RCP4.5, and RCP6.0, and it will decline under RCP8.5. The SOC and VCSES values are predicted to increase, except under RCP8.5. The dramatic declines can be found from the near future (2020-2039) to the very far future (2080-2099) period. Our finding indicates that even though climate change will have negative effects on SOC and VCSES, the OF will have less impact compared with CF.