Tuesday, May 18, 2010

Are cows really the problem? Climate change and farming.

“It’s the fastest way to sequester carbon, collect solar energy, and rebuild soil. Grazing is truly amazing.” Joel Salatin, Virginia farmer and author

I tried to ignore the headlines a few years ago about cows contributing more to global warming than cars – and waited for the smoke to clear and the data to settle itself out. It didn’t make intuitive sense, and when I was forwarded an email last week that insisted Gulf Island farms would need to get rid of cows and sheep and our pastoral life to combat climate change, that hit a little too close to home. The impacts attributed to livestock are based on incomplete information, since it is often forgotten that we are dealing with a system of interrelated biological processes. Efforts to stop global warming have been focused almost entirely on reducing emissions caused by man, not in taking existing carbon out of the atmosphere (a process known as carbon sequestration). Scientists are trying to unscramble the omelette and get the whole picture, while policy makers point fingers, but it is a race against time.

According to BC’s 2007 GHG (greenhouse gas) Emissions Inventory, transportation is the biggest emitter in our province at 36%. Agriculture is down at 3.4%, with 1% attributed to enteric fermentation by ruminants (cows mostly), and 0.5% to manure management. The world picture is different, with 10-14% of human-caused GHG from agriculture. But that is just the emissions, and the carbon cycle is just that – a cycle. Our forests, oceans and grasslands are carbon sinks, acting to absorb carbon. Although not included in most of the carbon-counting schemes, scientists have long been aware of grassland’s ability to capture or “sequester” carbon. The FAO made a presentation to COP15 requesting the inclusion of grasslands in carbon accounting, especially notable since 70% of the world’s agricultural lands are pasture and grassland. Grass takes in carbon dioxide from the air, converting it to sugars by photosynthesis. Some of the resulting carbon compounds are transferred to the roots and released into the soil through the normal cycles of growth and decay. Cows on a grass diet produce more methane than those fed on cereal grains, but grasslands more than compensate. Some pasture plants, such as bird’s-foot trefoil, are known to reduce methane emissions. There are soil bacteria that oxidize methane as well. .The grass takes in carbon from the atmosphere; the animals trample the grass into the soil, where the carbon is absorbed; new grass sprouts and the process is repeated over and over again, absorbing more and more carbon. This management system has been attributed to African game rancher Allan Savory, who observed that soil is healthiest and best able to absorb carbon when grasslands are managed in a way similar to the natural cycles created by huge herds of hoofed animals feeding on and trampling grasses for short periods and then moving elsewhere to avoid predators. Savory calls his method “Holistic Management”, and it is successfully practised by many ranchers in BC, and in other regions of the planet.

Converting croplands to pasture, which reduces erosion, effectively sequesters significant amounts of carbon. Grazing reduces the need for the fertilizers and fuel used by farm machinery in crop cultivation. Compared to cropland, perennial pastures used for grazing can decrease soil erosion by 80 percent and markedly improve water quality. According to the UN, “there is growing evidence that both cattle ranching and pastoralism can have positive impacts on biodiversity”. By improving our grasslands, improving our soils and our agricultural methods, and replenishing our forests we can do much to increase the uptake of excess atmospheric greenhouse gases, while reducing their emissions.

The idea of soil sequestration is still under the radar, according to Soil Science Professor Chuck Rice of Kansas State University, a member of the IPCC panel who directs a joint project of nine American universities and the U.S. Department of Energy studying the potential for reducing greenhouse gases through agricultural practices. Because there is more carbon stored in the soil than in the atmosphere, improvements in managing the carbon in the soil would make big differences in the atmosphere. By adopting a wide range of carbon sequestration strategies, ranging from planting more trees to cultivating crops using sustainable and no-till agriculture (which minimizes plowing) to raising animals on grasslands instead of feedlots—more problems than climate change could be solved.

Dr. Jan Coulter, a scientist and farmer in Scotland, was curious about her farm’s carbon footprint, and produced software for farmers to calculate their own carbon footprint, and it is available free online as Cplan. Other countries have produced software, and the Canadian version – Holos – is currently being tested by various associations and farmers across Canada. I tried out Holos, putting in our farm’s data and Stats Canada data from the 2006 Census on Agriculture, specifically for the southern outer Gulf Islands (Mayne, Galiano, Pender, Saturna and their accessory islands). In the southern outer Gulf Islands, we had 89 farms according to the 2006 census – almost 3000 ha attributed to farming; about 1300 ha of that pasture, 250 ha hay, 365 ha crop, and 1055 ha forest. We had 454 cattle and calves, 1447 sheep, 89 goats, 2526 poultry. Even without counting the sequestering effect of the farms’ forests, the effect of livestock was negated by the carbon uptake of the land. Not only can our farmers relax at the fact that we are balanced and carbon neutral, but there is room to use our farms in sequestering carbon and perhaps provide some solutions for the future. The Holos program gives suggestions on what changes could be made on your farm to improve carbon storage and reduce emissions. Improvements of 40-80% can be achieved by planting trees, reducing animal stocking rates and reducing nitrogen fertilizer. Smaller improvements (20-40%) can be achieved by improving the diet of livestock, improving nitrogen efficiency, manure management and changing the farm’s cultivation practices. Farmer testimonies have been positive – the programs are simple to use, and give the farmer a concrete value for his farm’s emissions and sinks, suggestions to improve the net result that are both reasonable but also profitable in the long run. Farmers can make slight changes using the program and model “what if” situations for their own farm. Further improvements to these programs are ongoing.

Viewing the world holistically will allow us to see that the best way to fix climate change is to involve the earth in the solution. The best way to unscramble the omelette is to feed it back to the hen, and let her lay a new egg. We certainly can’t do it alone.

“If farmers are empowered by knowing and understanding how their own carbon footprint is calculated they will be in a better position to influence policy and implement change without it being imposed upon them.”

Dr. Jan Coulter, developer of Cplan

No comments:

Post a Comment