MONTREAL — Quebec is moving to launch its cap-and-trade system to regulate greenhouse gas emissions beginning in 2013, following a year of transition. The long-awaited system is expected to be passed into law this fall after a 60-day public consultation period. The program is designed to reduce Quebec’s emissions by 20 per cent of 1990 levels by 2020. “Proving its leadership, vision and determination, Quebec is demonstrating that governments can play a fundamental role in the battle against climate change,” Quebec Environment Minister Pierre Arcand said. The minister described the emissions reduction as the most ambitious in North America. It is part of a co-ordinated regional effort of the Western Climate Initiative, which includes Ontario, Quebec, British Columbia and Manitoba representing 79 per cent of the Canadian population and economic activity. Saskatchewan, Nova Scotia, New Brunswick and the Yukon are observers.