Including Methane Emissions from Agricultural Ponds in National Greenhouse Gas Inventories

Area of Science:

• Environmental Science
• Climate Science
• Remote Sensing

Background:

• Agricultural ponds are a notable source of greenhouse gases, impacting climate change.
• Accurate national greenhouse gas inventory reports require accounting for these emissions.
• Existing methods may not fully capture dynamic changes in pond emissions.

Purpose of the Study:

• To develop and validate a remote sensing approach for estimating methane emissions from agricultural ponds.
• To account for monthly surface area fluctuations, historical pond accumulation, and temperature effects on emissions.
• To provide data for national greenhouse gas inventory reports and inform mitigation strategies.

Main Methods:

• Utilized open-access satellite imagery for remote sensing.
• Incorporated monthly variations in pond surface area.
• Modeled historical pond accumulation rates and temperature-dependent methane emission factors.
• Applied the method to Australian agricultural ponds for case study analysis.

Main Results:

• Total annual methane emissions from Australian agricultural ponds increased by 58% between 1990 and 2022.
• This rise correlates with a 51% increase in pond surface area (115 to 173 kilo hectares).
• An average methane flux of 0.238 t CH4 ha-1 year-1 was observed, with 1,230 ha of new pond surface added annually.

Conclusions:

• The remote sensing approach provides a robust method for estimating agricultural pond methane emissions.
• Findings highlight the growing contribution of agricultural ponds to national greenhouse gas inventories.
• Policy interventions, like financial incentives, can mitigate these emissions and improve pond environmental value.