Carbon offset is the purchase ("offsetting") of greenhouse gas emissions. It is commonly associated with offseting the greenhouse gas emissions from air travel, but may be used in many contexts.

The critical issue is how effective the offsets are - for example, if trees are planted, when are they planted, and how long before they absorb significant amounts of greenhouse gases - or indeed, whether they are planted at all.

Additionality

For a project to generate legitimate carbon offsets it has to be additional - not "business as usual projects" such as projects that would have been done anyway to comply with new laws or to reduce energy costs.

If renewable energy is sold under the banner of green power, the carbon credits they may earn should not be sold separately for an income stream - this is effectively selling the "green" aspect of the energy twice, and the green power customers are not having the positive benefit they intended by paying a premium for green power. This problem can occur through lack of transparency and oversight.

Personal measures

It may be worth asking whether there are personal measures that could have a similar impact, but more effectively. Planting a tree, buying a more fuel-efficient car, putting up sun shields as a passive solar design measure, purchasing a solar hot water heater (or space heater), insulating your house or eating less meat may be more effective than paying for carbon credits. Some will be very costly (buying a new car, if you didn't have plans to do so anyway) while others may put you financially in front within 3 years[verification needed] (solar hot water).

Choosing carbon offsets

In brief:

Detailed version - if you intend to do it as thoroughly as possible:

Problems with offsets

The fundamental problem with offsets is that fossil fuel combustion takes carbon out of the lithosphere, and puts it into the atmosphere, which is part of the biosphere. Soil, vegetation, oceans and atmosphere will equilibrate at a higher level.

Planting trees does nothing to help this, except perhaps speed up the equilibration. It doesn't put carbon back in the rocks, which would be the only true "offsetting".

Other offsetting schemes, such as funding the production of wind- or solar-power, also do nothing to reduce the net amount of carbon leaving the lithosphere and entering the atmosphere, but only offset potential increases in future greenhouse gas emissions, by displacing fossil fuel production.

Notes

  1. ↑ Tips for buying offsets - Carbon Offset Watch (Australia), via archive.org

See also

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Keywords Climate change, Carbon footprint, Energy efficiency, Ecological footprint, Renewable energy
SDG SDG13 Climate action
License CC-BY-SA-3.0
Language English ()
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Created November 1, 2007 by Chris Waterguy
Last edit November 28, 2025 by Maintenance script