Land Use Effects on Aquatic Fluxes of Greenhouse Gases from Ponds and Ditches (LEAF-PAD)

The 2019 Intergovernmental Panel on Climate Change (IPCC) Refinement chapter on wetlands, on which I am a contributing author, states:“At present, available data are not sufficient to derive emission factors [EFs] for any category [of pond] by climate zone, or to disaggregate emissions from canals, drainage channels and ditches.

Disaggregation by surrounding land-use, nutrient loading and/or yield is also not currently possible.”Here, I propose a project to quantify emissions of greenhouse gases (GHGs) and carbon (C) burial in artificial ponds and ditches across a range of land uses (urban, agriculture, forest) and regions.

Future urban growth and intensified agricultural drainage will likely increase the number of these waterbodies and current, limited data suggest that they could be hotspots for GHG emissions and C storage. However, full multi-site, multi-year GHG/C balances for these types of waterbody do not exist.

On a landscape scale, ponds and ditches occupy cumulatively large areas, potentially making them significant contributors to climatic warming.

Fieldwork will quantify EFs and controlled lab experiments will untangle drivers (eutrophication, temperature, drought/rewetting) of GHG production and C storage. The new EFs will fill the knowledge gap highlighted by the IPCC.

The project will also pave the way for appropriate climate mitigation actions aimed at enhancing C storage and lowering GHG emissions for this important but understudied group of waterbodies.