By Gary Yohe and Roger Kuhns MIDDLETOWN/MYSTIC – In 2005, the European Union established the HYPERLINK "https://climate.ec.europa.eu/eu-action/eu-emissions-trading-system-eu-ets_en" \t "_blank"Emissions Trading System, the world’s first, and largest, market for carbon allowances. Following a cap-and-trade approach, the ETS functions as an open market for trading emissions