Offsetting carbon or removing carbon from the atmosphere has become one of the many solutions to increasing carbon emissions. The US and UK have been doing carbon trading for some time to neutralise their carbon emissions from their industries and individual emissions.
How carbon offsetting works
A carbon-offsetting scheme works when individuals or companies invest or pay for environmental projects worldwide to balance their carbon footprint. The projects are usually based in developing countries and are most commonly designed to reduce future emissions (Clark, 2011).
This can involve introducing clean energy technologies or soaking up CO2 directly from the air by planting trees, Clark (2011) says.
For example, a typical British family would pay around 45pounds to neutralise a year’s worth of gas and electricity use, and a return flight from London to San Francisco would be around 20 pounds per ticket.
In the Western hills of Montana, ranchers are paid to let their grasses grow to offset carbon in the atmosphere; one ranch owner received a $30 thousand check for the carbon absorption its grasses do (Ahearn, 2008).
While purchasing carbon credits from ‘polluters’ is voluntary, how it works is through their “cap and trade” system.
Ahearn (2008) explains further:
- Ten northeastern states have agreed to implement an upper limit to the amount of greenhouse gas emissions the industries can release into the atmosphere. If they exceed the limits, companies will purchase carbon credits to neutralise their emissions like the stock exchange market.
- This scheme has successfully reduced sulphur dioxide emissions, which are responsible for acid rain.
- Not all ranches are equal regarding the amount of carbon it absorbs, and they must pass a method of soil tastings and the amount of rain it receives each year.
Fertile grasslands can absorb 20 per cent more carbon than arid soils, says Joel Brown, a rangeland management specialist at the US Department of Agriculture’s Natural Resources Conservation Services. He helps determine how much to pay ranchers for sequestering carbon (Ahearn, 2008).
How carbon is absorbed into the soil
In Ahearn’s Scientific American article “Carbon-Offset Cowboys Let Their Grass Grow,” here is how it works:
- Grass absorbs carbon dioxide the same way trees do, but on a smaller scale through photosynthesis, when a plant takes carbon from the atmosphere and uses it to build more plant matter. When grasses die or trees are cut down, it releases carbon dioxide into the atmosphere, but their roots also release carbon into the soils’ fungi.
- Stephen Porder, a biogeochemist at Brown University, says that when roots or fungi die, it is eaten by some microbe or worm, and a portion of that carbon gets stabilised. It gets stuck into a clay mineral or a particle and stays in the soil.
- The best way to maximise the amount of carbon absorption in the soil is to maximise grass growth.
- Overgrazing and drought are the biggest challenges to carbon sequestration because they prevent plants from putting down healthy roots.
Best management practices in ranch farming are crucial
For ranchers to continue trading carbon offsets, Ahearn (2008) pointed out:
- One of the vital things they did was to cut the number of its cattle.
- They also need to show even grazing rotations around the ranch and a plan to prevent overgrazing in drought.
- Ranchers will also have to agree to be audited annually to ensure that they follow the requirements to continue with carbon trading.
The Chicago Climate Exchange, a body that oversees carbon trading, says that it is ‘wary’ of relying too much on rangelands for carbon sequestrations because they do not absorb as much carbon as rain forests do, plus that the science on how grazing and droughts affect soil sequestration is relatively new.
For ranch owners, their contribution to carbon absorption may not be very significant, but this is an opportunity for them to apply ‘best management practices, says Michael Walsh, executive vice president of the exchange (Ahearn, 2008).
Clark, D. (2011, September 16). A complete guide to carbon offsetting. The Guardian. Retrieved from https://www.theguardian.com/environment/2011/sep/16/carbon-offset-projects-carbon-emissions
Ahearn, A. (2008, December 1). Carbon-offset Cowboys Let Their Grass Grow. Scientific American. Retrieved from https://www.scientificamerican.com/article/carbon-cowboys/