Which prominent political leader said this, in 1988?

“For generations, we have assumed that the efforts of mankind would leave the fundamental equilibrium of the world’s systems and atmosphere stable. But it is possible that with all these enormous changes – population, agriculture, use of fossil fuels – concentrated into such a short period of time, we have unwittingly begun a massive experiment with the system of this planet itself.”

I’ll post the answer tomorrow (Valentine’s Day, and that’s not a clue).