Carbon Offsetting – A Climate Adaptation and Mitigation Option

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 45 pounds to neutralise a year’s worth of gas and electricity use, and a return flight from London to San Francisco would cost 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, it works through their “cap and trade” system.

Ahearn (2008) explains further:

• Ten northeastern states have agreed to implement an upper limit on the amount of greenhouse gas emissions 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 that are responsible for acid rain.
• Not all ranches are equal regarding the amount of carbon they absorb, and they must pass a method of soil tastings and the amount of rain they receive 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, they release carbon dioxide into the atmosphere, but their roots also release carbon into the soil’s fungi.
• Stephen Porder, a biogeochemist at Brown University, says that when roots or fungi die, they are eaten by some microbe or worm, and a portion of that carbon is stabilised. It then gets stuck into a clay mineral or particle and stays in the soil.
• The best way to maximise the 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 cattle.
• They also need to show even grazing rotations around the ranch and a plan to prevent overgrazing in drought.
• Ranchers must also 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 it is ‘wary’ of relying too much on rangelands for carbon sequestration because they do not absorb as much carbon as rain forests do. The science of 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).

Afterthought

Imagine if all countries diligently adopted and practised their carbon offsetting and sequestration programs. Then, climate adaptation and mitigation would be elevated to a new level.