Many types of offsets exist, but they fall into two broad groups: emission reductions and carbon removals.
Emission reductions generally relate to projects that reduce carbon emissions by taking a specified action compared to a reference scenario, whereas greenhouse gas removals take greenhouse gases from the atmosphere and permanently sequester them.
Examples of emission reduction offsets include reducing or capturing emissions of harmful, long-lived pollutants and avoiding deforestation. Examples of carbon removal offsets include nature-based solutions such as the restoration of peatlands, coastal habitats, and native forests, and technology-based solutions such as direct carbon capture or mineralizing CO2 into building materials.
This area has been beset with controversy since there are a wide variety of schemes, largely unregulated which vary in quality and some of them have very questionable greenhouse gas benefits. There are several verification and certification schemes which attempt to address this. Carbon offsets can be used to achieve the standard PAS 2060 – Carbon Neutrality. To achieve net zero, any remaining emissions should be balanced with an appropriate amount of carbon removals using certified greenhouse gas removals. Possible greenhouse gas removal options include large-scale afforestation and bioenergy with carbon capture and storage.
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