At Kyoto in December 1997, Al Gore told the American delegation to show flexibility, provided the treaty contained market mechanisms. The resulting carbon market began as three sentences saying trading could happen and the rules would follow. The United States never ratified, Russia held the key to the treaty's life, and the 1990 baseline left billions of tonnes of surplus "hot air." Parties still complied, at about a tenth of forecast cost.
Whether Kyoto worked is argued. Compliance at a tenth of forecast cost is set against reliance on a 13.4 billion tonne surplus, sink credits, and the exit of two Parties. The split between hot air and legitimate headroom, and the formal bargain between Russia's ratification and WTO support, are also disputed.



