Answer:
failed because developing countries were exempt.
Step-by-step explanation:
The "Kyoto Protocol" was an international agreement that aimed to cut down the global gases around the world. It was adopted first in Kyoto in 1997. This was the time when the concern for the rising greenhouse gases was alarming. It mandated the countries which were industrialized to cut down their global emissions, this included the USA.
Although the U.S.A signed the agreement at first, they dropped out from it because they felt it was unfair since the developing countries like China and India were exempted from it. The protocol failed because most of the emissions came from the developing countries which were exempted and this increased the overall gas emissions around the world.