In which year did the Kyoto Protocol conic into force?
**Core Concept**
The Kyoto Protocol is an international treaty that sets binding targets for developed countries to reduce their greenhouse gas emissions. The protocol aims to mitigate climate change by promoting the adoption of cleaner energy sources and reducing dependence on fossil fuels.
**Why the Correct Answer is Right**
The Kyoto Protocol entered into force on February 16, 2005, after being ratified by more than 55 countries that accounted for 55% of the total carbon dioxide emissions of the industrialized countries in 1990. This marked a significant step towards international cooperation on climate change mitigation. The protocol established a flexible mechanism for countries to meet their emission reduction targets, including the Clean Development Mechanism (CDM) and Joint Implementation (JI).
**Why Each Wrong Option is Incorrect**
**Option A:** 1997 - This is the year the Kyoto Protocol was adopted at the third session of the Conference of the Parties (COP-3) to the United Nations Framework Convention on Climate Change (UNFCCC), but it did not enter into force until 2005.
**Option B:** 2000 - This is the year the Kyoto Protocol was signed by the United States, but it did not enter into force until 2005.
**Option C:** 2007 - This is the year the Kyoto Protocol's first commitment period ended, but it did not enter into force until 2005.
**Clinical Pearl / High-Yield Fact**
The Kyoto Protocol's entry into force marked a significant milestone in international cooperation on climate change mitigation. The protocol's flexible mechanisms, such as the CDM and JI, have been instrumental in promoting the development and transfer of cleaner technologies to developing countries.
**Correct Answer: D. 2005**