June 5 (Bloomberg) -- The International Air Transport Association began a carbon-offset program so airlines can help passengers compensate for carbon-dioxide emissions by making financial contributions to environmental projects in developing countries.

The program is designed for airlines that haven’t chosen to come up their own measures, Giovanni Bisignani, IATA’s chief executive officer, said today in an e-mailed statement. TAP SGPS SA, Portugal’s state-owned airline, is the first to take part, Montreal- and Geneva-based IATA said.

The plan will calculate carbon emissions based on a methodology developed by the International Civil Aviation Organization. The program uses IATA’s existing financial systems to enable airlines and their passengers to purchase tickets and offsets at the same time.

Passenger participation is voluntary. TAP has chosen Brazil’s Aquarius Hydroelectric Project as its renewable energy program.

To contact the reporter on this story: Andrea Rothman in Toulouse, France at aerothman@bloomberg.net.

Last Updated: June 4, 2009 21:00 EDT