A financial instrument representing a reduction in greenhouse gas emissions. One carbon offset represents the reduction of one metric ton of carbon dioxide, or its equivalent in other greenhouse gases. There are two primary markets for carbon offsets. In the larger compliance market, companies, governments or other entities buy carbon offsets in order to comply with caps on the total amount of carbon dioxide they are allowed to emit. In the much smaller voluntary market, individuals, companies, or governments purchase carbon offsets to mitigate their own greenhouse gas emissions from transportation, electricity use, and other sources. Milliken has achieved its certified carbon negative status without the purchase of offsets, using internally generated credits.