Explanation:

Kyoto Protocol.

The concept of carbon credits originated from the Kyoto Protocol, an international treaty that extends the 1992 United Nations Framework Convention on Climate Change (UNFCCC). The protocol, adopted in Kyoto, Japan, in 1997, introduced mechanisms like carbon credits as part of efforts to reduce greenhouse gas emissions and mitigate climate change. These mechanisms allow countries or entities to earn carbon credits by reducing emissions, which can then be traded to help meet their emission reduction targets.