Description:A treaty confirming the air industry's commitment to battling climate change. But as aviation leaders signed the pact in Geneva, the threat of a global trade war edged closer. India has become the latest country to threaten a boycott of the EU's Emissions Trading Scheme. It will ask local airlines not to buy carbon credits from, or share emissions data with the bloc. China has already suspended the purchase of 14 billion dollars worth of planes from Airbus due to the dispute.(2:08)