The Kyoto Protocol is an international treaty which extends the 1992 United Nations Framework Convention on Climate Change (UNFCCC).
A total of 192 countries have signed and ratified the Kyoto Protocol.
The main goal of the treaty is to reduce greenhouse gas emissions.
The Kyoto Protocol also introduced the concept of emissions (carbon) trading.
When it was written, the treaty was not legally binding. The protocol didn't become international law until more than halfway through the 1990–2012 period.