Japan should start focusing more diplomatic attention on Russia if it wants to put the Kyoto Protocol climate change agreement into force -- with or without the United States.

So says Michael Grubb, professor of climate change and energy at Imperial College in London and an authority on the Kyoto Protocol.

Now that Japan's superpower ally on the other side of the Pacific has announced it will opt out of the accord, the support of Japan and its northern neighbor will be crucial to putting the protocol into force, Grubb said in an interview with The Japan Times.