METHANE emissions from cattle grazed under Australian conditions are nowhere near as high as previously thought, important new research has shown.

Emissions from cattle in Australia are 24 percent lower than previously estimated – the equivalent to 12.6 million tonnes of carbon dioxide a year – following analysis of new Australian research data.

The results have led to an update of the National Greenhouse Gas Inventory (NGGI).

The research was undertaken by scientists from across Australia, and was based on data collected over eight years of research into ways to reduce methane emissions in Australian livestock as part of Meat & Livestock Australia’s methane abatement research programs.

The new methodology also brings the NGGI in line with the estimates of the Intergovernmental Panel on Climate Change (IPCC), the leading international body on the assessment of climate change, which was established by the United Nations Environment Program and the World Meteorological Organisation in 1988.

Ed Charmley

CSIRO Agriculture‘s research scientist, Dr Ed Charmley, said the work was conducted because of concerns about the large differential between NGGI and IPCC methane emission figures for Australian cattle, and doubt surrounding the accuracy of previous calculation methodologies used for cattle, particularly northern Australian cattle.

Different methods used to calculate emissions from livestock in temperate and tropical regions were based on studies done in the 1960s and 1990s, mainly with dairy cattle, Dr Charmley said.

Both of these past methods were found to be likely over-estimating the emissions from cattle.

“The revised method, which is based on improved ways of estimating ruminant methane emissions from forage-fed beef and dairy cattle, be they in temperate or tropical regions, has been tested against international defaults provided by the IPCC and found to give consistent methane yields,” Dr Charmley said.

MLA general manager, on-farm Innovation, Dr Matthew McDonagh, said the results provided an accurate dataset which clearly showed Australian cattle contributing substantially less to methane emissions than previously believed.

“This revelation clearly shows livestock-based emissions are nowhere near what they were thought to be, and will help improve the accuracy of Australia’s national greenhouse gas emissions estimates,” Dr McDonagh said.

“This is positive news for the Australian livestock sector as it seeks to continually improve its production efficiencies and demonstrate its environmental credentials.”

MLA’s manager for sustainable feedbase, Dr Tom Davison, said the research findings from the National Livestock Methane Program also showed there were a number of simple management measures that producers could implement to substantially reduce methane emissions while increasing productivity.

“Some of these are as simple as integrating leucaena into grazing systems, improving growth rates or herd reproductive performance, while other future techniques may include feeding red-algae to livestock and have been prioritised for further research,” he said.

“We look forward to continuing to make further gains in this field for the mutual benefit of both our livestock industries and environmental sustainability,” Dr Davison said.

The latest analysis of Australian cattle research data was conducted by CSIRO, the Victorian Department of Economic Development & Resources, the NSW DPI, the University of New England and the Queensland Department of Agriculture and Fisheries, with technical input from the Australian Government Department of Environment.

• The new method has been published online this month in the journal Animal Production Science.
• Click here to view the full research paper.

Source: MLA