Look at emissions from farm dams
FARM dams are a major contributor to climate change, a study from a Deakin University PhD student contends.
The study says each waterhole produces about the same amount of greenhouse gas emissions as a car, due to microbes in dams that release carbon dioxide, methane and nitrous oxide.
However, according to the scientist behind the work, emissions from dams could be halved with “simple” changes to farming practices.
Lead author Quinn Ollivier, a PhD candidate in Deakin’s Blue Carbon Lab, found Victoria’s 375,000 farm dams produce the equivalent amount of greenhouse gas emissions as 385,000 cars.
Mr Ollivier’s study found dam emissions were caused by dissolved nitrate concentrations and were significantly higher on livestock farms compared with cropping areas.
Slashing nitrate levels by a quarter by “minimising excess fertilisation and containing animal effluent”, he estimates emissions from some dams could be halved.
While the study found dams had one of the highest emissions of all freshwater ecosystems, they were not accounted for in governmental emissions budgets.
Mr Ollivier said that provided an “enormous opportunity” for governments to work with landholders to manage nutrients. He said farm dams “may be emitting three times more carbon into the atmosphere than freshwater reservoirs”.
“Landholders may be able to reduce emissions by something as simple as re-plantation of native plants along dam edges, this could help to reduce nutrients entering the dam and therefore the greenhouse gases coming out,” Mr Ollivier said.
He said satellite networks had only made it possible to assess the distribution of farm dams in the past decade.