Twenty years ago, Brian Mulroney and George H.W. Bush signed the Acid Rain Accord. Since then, the landmark air quality agreement and its cap-and-trade program have reduced acid rain levels and SO2 emissions by a remarkable 40 per cent. It is a rare and remarkable example of a successful agreement of environmental policy between Canada and the United States.

National Green Party leader Elizabeth May, a senior federal government policy advisor and executive director of the Sierra Club at the time of the accord, spoke with the former prime minister to reflect on the breakthrough treaty. She and Brian Mulroney discussed challenging negotiations, the importance of Canadian leadership when confronting environmental issues with the U.S., and the lessons we should learn when planning effective climate change strategies going forward.

Elizabeth May: Can you recall the first time you heard the term "acid rain"? To me, it was a better way of communicating a problem than anything we've come up with to describe the climate crisis.

Brian Mulroney: I remember first hearing it around 1980, and I agree with you: the words acid rain conjure up, in a very graphic way, the reality of the problem--as opposed to air quality agreements, or even more benign descriptions. Acid rain was like a menace coming right at us, at our lakes, rivers and streams, and so people tended to get it right away.

Elizabeth May: Acid rain had been on the radar for the previous two governments, but it wasn't until you were prime minister that it became the top bilateral issue for Canada when dealing with the United States. How did that happen?

Brian Mulroney: When I became leader of the party in 1983, I insisted that acid rain be placed on our agenda on a priority basis within the opposition study group system that I had implemented. In June 1984, when I went down to Washington as leader of the opposition for my first meeting with President Reagan, I raised the acid rain challenge with him in the oval office. I told him that if I were successful in the next election, I would be back to see him soon, and often, in regards to the ultimate resolution of this problem. So we made it a priority and we followed through.

Elizabeth May: DId you feel that you had an uphill battle in convincing Reagan to take this issue seriously?

Brian Mulroney: We certainly had an uphill job because, in the course of the negotiations of other things, I transformed the acid rain treaty into what I called the litmus test of our valued association. If we couldn't make progress on that, then we were going to be in trouble. There was the time that [Reagan] sent Vice-President Bush to Ottawa to see me, and Bush famously told the media, "Boy, did I ever get an earful today from Prime Minister Mulroney." And when I was invited to address the U.S. Congress, I got into the acid rain challenge at considerable length. The leading Democratic senator from New York, Daniel Patrick Moynihan, said he was really stunned by Prime Minister Mulroney's description of the problem and the urgency he attached to it, and he stated that they had to respond in kind.

Elizabeth May: Canada's complex federation is often cited as a reason we don't make progress on environmental issues, because the mixed and shared jurisdiction gets in the way. But you achieved agreements with each of the eastern provinces and firm agreements through bilateral agreements. What were the elements of making that work?