"The most compelling environmental challenge facing the world today is global warming. In Toronto in 1988, we hosted the first international scientific conference on climate change. The scientists gathered there told us in clear, unambiguous language the nature of the challenge we were facing. In their consensus statement, they concluded: 'Humanity is conducting an unintended, uncontrolled, globally pervasive experiment, whose ultimate consequences are second only to global nuclear war.' "
- Former Progressive Conservative Prime Minister Brian Mulroney, April 20, 2006