However, due to the complex, novel mechanisms in the Protocol and the political difficulties in achieving agreement on how those mechanisms would be implemented, the Kyoto Protocol did not enter into force until 2005.
然而，由于该议定书的复杂、新颖机制，以及就如何落实这些机制达成协议的政治困难，《京都议定书》直至2005年才得以生效。