Currently there are developing registries at both the federal and state levels in the USA as well as a number of non-governmental organizations that have developed accounting protocols. The Kyoto Protocol is also included in the table below since it is the benchmark by which many of the other protocols are judged. Currently, the USA is not a signatory to the Kyoto Protocol so the developing protocols and regestries in the USA may differ in the acceptable approaches for carbon sequestration or carbon accounting.
A system that tracks greenhouse gases Kyoto units (tonnes of assigned amounts of CO2). A firm can move their Kyoto units can be moved from one country to the next so the registry needs to be able to track these units at all times, no matter the location. In addition to recording the holding of Kyoto units, these registries will handle settlement of the emissions trades by delivering units from the accounts of sellers to the buyers. Each registry will operate through a link established with the International transaction log put in place and administered by the UNFCCC secretariat. Domestic or regional trading schemes that use Kyoto units also undertake their settlement through these registry systems. 
Types of Registries
The two types of registries that are being implemented are:
- Governments of the 38 Annex B Parties are implementing national registries, containing accounts within which units are held in the name of the government or in the name of legal entities authorized by the government to hold and trade units.
- The UNFCCC secretariat, under the authority of the CDM Executive Board, has implemented the CDM registry for issuing CDM credits and distributing them to national registries. Accounts in the CDM registry are held only by CDM project participants, as the registry does not accept emissions trading between accounts.
- California Climate Action Registry
- APX Environmental Markets Registry
- Georgia Forestry Commission
- Regional Greenhouse Gas Initiative
- Chicago Climate Exchange