The OECD countries agreed to reduce funding for coal power in other countries, but Japan blocked eliminating this funding.

This may do some good, but it is not the sort of vigorous action that could save civilization from global disaster. To risk civilization's survival for a comparatively small short-term goal, such as improving access to electricity in some poor countries, is foolhardy. It won't help the people of those countries to get electricity in the next decade, then wiped out in 70 years.

Besides, solar power is much better for providing electricity to dispersed rural populations.

I have to suspect that Japan's representatives were working for the coal interests and what they said was just an excuse.