Modelling the Impact of the Spread of Wet Rice Cultivation on Atmospheric Methane Levels from Archaeobotanical Data

Abstract:

This paper will model the impact of Asian rice cultivation in the atmospheric methane levels of the later half of the Holocene. Wetlands, whether natural or landscaped, are a major source of atmospheric methane. The spread of rice cultivation in the second half of the Holocene was a key driving force in the creation of flooded (‘paddy’ or ‘wet’) fields throughout Asia but their impact on atmospheric methane levels is poorly understood. A database of more than 470 georeferenced and dated archaeobotanical entries will be used to understand the spread and impact of wet rice cultivation in Asia. Two modelling approaches will be used: one based on spatial interpolation of the archaeobotanical database (Fuller et al. 2011) and another based on a Fast Marching method that accounts for biogeography affecting the routes and rates of spread (eg Silva and Steele 2014). In addition, different models for methane emissions from wetlands will be employed (eg Walker et al. 2001, Ringeval et al. 2010) and their estimates compared with the Greenland Ice Core data for Holocene atmospheric methane.

References

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Silva F and Steele J (2014) New methods for reconstructing dispersal rates and routes from large-scale radiocarbon databases. Journal of Archaeological Science 52: 609-620.

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