The Kyoto Protocol, an international agreement to combat climate change, came into force in the year 2005. The protocol was adopted in Kyoto, Japan, in December 1997 and aimed to reduce greenhouse gas emissions globally. It set binding emission reduction targets for developed countries, known as Annex I countries, for the period 2008-2012. Each country was assigned a specific emissions reduction target based on their individual circumstances. The Kyoto Protocol has played a significant role in raising awareness and promoting action on climate change. It has been ratified by numerous countries and has paved the way for future international climate agreements. Therefore, the correct answer is option 2.