On 23 November 2017 the EU and Switzerland signed an agreement in Bern to link the Swiss emissions trading scheme with that of the EU, the so-called Linking Agreement. The Linking Agreement was ratified by both parties in December 2019 and it entered into force on 1 January 2020. It is the first international treaty linking emissions trading schemes anywhere in the world.
Under this agreement, participants in the EU Emissions Trading System (EU ETS) are allowed to use allowances from the Swiss system for compliance, and vice versa. Compatibility between the ETSs, the equal treatment of participants and system security are ensured by, among other things, 'essential criteria' laid down in the Annexes to the Agreement.
In order to manage the agreement, a Joint Committee has been established. This Joint Committee may, in particular, decide on amendments to the Annexes. The Agreement is geared towards long-term cooperation and is therefore not time-limited.
Some figures : The EU-ETS includes just under 11 000 operators of fixed installations, representing emissions of around 2 billion tonnes of CO2 equivalent (CO2eq), as well as over 500 aircraft operators, which account for emissions of around 65 million tonnes of CO2. Whilst around 50 operators of fixed installations participate in the Swiss ETS, with emissions totalling approximately 5 million tonnes of CO2eq.
More information on the implementation and the implications of the linking is available at the website of the European Commission https://ec.europa.eu/clima/policies/ets/markets_en#tab-0-3.