Step 1: Understand the question
The question is asking about the Kyoto Protocol, a major international treaty. We need to identify what global issue this treaty addresses.
Step 2: Background of the Kyoto Protocol
- The Kyoto Protocol was adopted in December 1997 in Kyoto, Japan, and came into force in 2005.
- It is an international agreement under the United Nations Framework Convention on Climate Change (UNFCCC).
- The central aim was to combat **global warming** by requiring industrialized countries to reduce their emissions of greenhouse gases (GHGs).
Step 3: Key features of the protocol
- The treaty set legally binding targets for 37 industrialized nations and the European Community.
- These targets were to reduce GHG emissions to an average of **5% below 1990 levels** over the commitment period of 2008–2012.
- The greenhouse gases covered included carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), and certain industrial gases.
- It introduced market-based mechanisms like **Carbon Trading, Clean Development Mechanism (CDM), and Joint Implementation (JI)** to help countries meet their targets.
Step 4: Global importance
- The Kyoto Protocol marked the first time that countries agreed to legally binding limits on greenhouse gas emissions.
- It also established a framework for future agreements such as the **Paris Agreement (2015)**.
Step 5: Conclusion
From the above explanation, it is clear that the Kyoto Protocol pertains specifically to **reducing greenhouse gas emissions** in order to fight climate change.
Final Answer: The correct option is (B): reducing greenhouse gas emissions.