Increasing production efficiency and profitability are two of many ways the livestock industry can help mitigate climate change, according to a University of Guelph expert on the topic.
Dr. Claudia Wagner-Riddle of the School of Environmental Science was the presenter at the latest webinar in the Horizon series developed by the Livestock Research Innovation Corporation (LRIC).
She and Dr. Susantha Jayasundara were also contributing editors to a white paper entitled “Livestock and Greenhouse Gases” written by LRIC CEO Mike McMorris and Chloe Neudorf.
- Why it matters: Livestock are vilified for the carbon they contribute to the atmosphere, but research shows that livestock efficiency has improved greatly.
Globally, Wagner-Riddle said the social costs of climate change from floods, droughts, earthquakes, storms and other natural disasters amounted to $2.91 trillion between 1998 and 2017 – two and a half more times the costs incurred between 1978 and 1997.
In Canada, Wagner-Riddle said livestock accounts for only 10 per cent of the country’s greenhouse gas emissions and eight per cent of Ontario’s, but “agriculture owns 100 per cent of that piece of the picture.”
The other categories are oil and gas, transportation, buildings, electricity, heavy industry and waste.
About half of agricultural emissions are attributed to the livestock sector and a third to crop production. In livestock, the sources are the animals themselves (mostly beef and dairy cattle), manure storage, soils after fertilizing, and energy, including fossil fuels.
Wagner-Riddle explained that a carbon footprint is another way of expressing greenhouse gas emission metrics, but it takes into account emissions generated during the entire supply chain.
She showed the carbon footprint of milk, and the on-farm piece of it, including milk and feed production, accounts for 70 per cent of the total. The other 30 per cent comes from processing, packaging, transportation/distribution, retail and consumers.
Wagner-Riddle’s lab conducted two studies regarding dairy’s carbon footprint. The first used Statistics Canada data over time.
“From 1991 to 2011, the carbon footprint (of dairy) was reduced and that has to do with efficiency of production,” she said. The 22 per cent reduction was the result of a number of metrics, including fewer cows and less manure plus increased feed and land-use efficiency.
While there’s a public misconception that methane contributed from cows comes from their rear end, 95 per cent of it actually comes from burps. Cows have a higher carbon footprint than chickens and pigs because they are ruminants.
“Remember, cows convert the food we can’t eat into good nutritious food we can eat, plus methane as a side product,” she said.
In a second analysis involving 200 farms that were surveyed over three years, 25 per cent of the farms with the highest profits had the lowest carbon footprint and the lowest profit makers had the highest footprint.
She then moved into what the industry is doing to reduce its carbon footprint.
“Things have improved over the past 20 years, and we’re looking to improve even more,” she said.
Carbon sequestration was up next, and Wagner-Riddle pointed out that many big companies like Microsoft are looking to agriculture to make up their carbon offsets to reach their goals of being carbon neutral or negative.
She presented an estimate that showed how, if perennial crops in pastures are maintained at their current levels and not allowed to be converted to annual crops, 62 per cent of the carbon emissions produced by the Canadian beef sector could be offset.
Wagner-Riddle countered arguments that annual crops are good carbon sinks by pointing out that above ground biomass like a corn crop would store only about 10 tonnes of carbon per hectare. Half of that goes to food or feed, so it doesn’t count, and the half that stays on the ground only stores carbon for a year or so.
“What we want to do is avoid the loss of carbon or gain carbon over time, and that’s a slow process,” she said.
The ways carbon can be gained are tied to regenerative agriculture principles: having pastures and grazing animals; diversifying crops and using cover crops; and increasing crop yields and returning residues to the soil.
Carbon loss reductions can be achieved by avoiding overgrazing, minimizing residue removal, using less tillage, reducing soil erosion and minimizing fallowing.