Feature Articles

Lessons in greenhouse gas reduction

November 23, 2006:

Studying greenhouse gas has given both scientists and producers a chance to learn more about the issue — and themselves

Greenhouse gases. Mention those words to many farmers and ranchers and you can almost certainly expect a reaction — a bit of fear, a dash of loathing, and maybe even a pinch of scientific intrigue.

Senior scientist Dr. Ray Desjardins, who has worked as a leading scientist on the subject, has witnessed all of those sentiments and more. For five years he played an advisory role in the Greenhouse Gas Mitigation Program (GHGMP), a national program dedicated to reducing greenhouse gases on farms and ranches.

The role not only offered him the opportunity to work on a leading and sometimes-controversial science, but also gave him the opportunity to sit between two camps which do not always see eye-to-eye: the agricultural and scientific communities.

Although it would be a stretch to say that greenhouse gas (GHG) reduction has become a front-line priority for most agricultural producers, Desjardins believes the GHGMP resulted in a better understanding of communication with producers. "And ultimately, it's helped produce better stewards of the land."

Communication counts

The GHGMP program gave the scientific and agricultural communities a chance to meet on common ground and create a dialogue, says Desjardins. This was driven by a decision to teach, rather than preach, the benefits of GHG-reducing production practices through a number of demonstration sites set up throughout Canada.

Demonstration sites gave producers the opportunity to see practices in action.
Demonstration sites gave producers the opportunity to see practices in action.

"Producers like to see results, and that's what the demonstration sites offered," says Desjardins. "They gave producers the opportunity to see beneficial management practices in action and gave us the chance to receive valuable input from the farming community. In turn, we provided them with tools, such as a GHG calculator, to help them quantify the greenhouse gas emissions on their farms and ranches."

Through this input, Desjardins and his fellow scientists learned that agricultural producers are concerned about the effects of climate change and interested in taking action to reduce GHG emissions.

"Climate change is clearly associated with GHG emissions, and farmers and ranchers understand the relationship it has to the sustainability of their farms and ranches. To them, climate change means the higher probability of drought, excess precipitation and a number of other extreme weather scenarios that could mean the loss of crops and livelihood. In short, it hits them where they live."

Science first, education second

As the GHGMP progressed, the scientists involved in the program realized that there was still a lot to learn about greenhouse gases. Desjardins admits that at the outset of the program they did not always have sufficient knowledge of the impact on GHG emissions of the management practices they were recommending to producers, particularly in the livestock component of the GHGMP.

"We learned the importance of having a better initial understanding of the science," says Desjardins. "If we had more information on the magnitude of GHG emissions associated with various management practices from the start, the program would have likely been more successful."

The upside to this is that they now have some key numbers to back up the efficiency claims of many of these practices. However, Desjardins says there is still work that needs to be done.

"There are a lot of practices which could be helpful in reducing GHGs, but we still need to quantify them before making recommendations to producers. As more accurate data is obtained, the education process will likely become easier for everyone involved."

Focus on production

In some ways, the initial lack of knowledge turned the research in new and progressive directions. At the outset of the program, the scientists involved took a somewhat linear approach to reducing GHG emissions among livestock animals, says Desjardins. As the program evolved, however, a greater emphasis was placed on reducing GHGs at the production end of the cycle and improving efficiency for the producer.

"Reducing GHG emissions on a macro scale is not the same as cutting them on every farm or ranch in production," says Desjardins. "The economic reality is that as demand increases, the number of animals on a farm or ranch operation increases, causing emissions of GHGs such as methane to increase as well.

"The question we had to ask ourselves was how we could look at GHG emissions in a broader sense. It is not enough to simply measure emissions; we should quantify GHG emissions per unit of production."

An example of this is found in the milk production of dairy cattle. "Back in 1990, we estimated that dairy cattle produced 116 kg of methane per cow per year. Now they produce around 136 kg of methane per cow per year. That seems like bad news until you factor in milk production. In 1990, dairy cows produced 22.5 litres of methane per kilogram of milk but today they produce 20 litres of methane for the same amount of milk."

Desjardins believes measurements of efficiency will drive the study of GHG mitigation among livestock in the future. "The producer gets an improved production efficiency while managing the amount of greenhouse gases produced on the operation at the same time — it's a win-win situation."

A cover crop protects the soil and manages nitrogen surplus to reduce nitrous oxide emissions.
A cover crop protects the soil and manages nitrogen surplus to reduce nitrous oxide emissions.

Other advances made over the past few years include the quantification of the impact of zero tillage and reduced summerfallow on soil conservation. "We now have a whole series of coefficients that we can apply towards a GHG offset program," says Desjardins. "Canadian soil has lost about 1,100 million tonnes of carbon since the beginning of cultivation. Thanks to practices such as reduced tillage, we're starting to reverse that process."

Advances have also been made in reducing GHG emissions during manure storage. The program included several projects in which various kinds of covers were used to reduce ammonia emissions and possibly capture methane. Soil and straw, for example, were used as a cover to act as a buffer which captures some of the emissions.

"Manure storage is an important source of GHGs, and these methods have a lot of potential for reducing the gas emissions which come from it," says Desjardins.

Learn from the world

In many ways, the five-year period the GHGMP covered was exceptionally timely for the research involved. "Over the time we did this study, a tremendous amount of information was obtained worldwide on GHG emissions," says Desjardins. "Staying plugged into this growing body of knowledge is key to the future of greenhouse gas reduction efforts."

It will also be important to continue to facilitate communication between producers and scientists and improve tools which can help them manage GHG emissions.

"Working closer with farmers and ranchers is the only way to go," says Desjardins. "The scientific community is not going to make any GHG emission reduction progress unless producers adopt the most promising management practices, and producers will not adopt the practices unless they're well-demonstrated and quantified — it has to be a mutually-beneficial process with communication in the driver's seat."