The thing that all these countries are signing (bar U.S., Aus, few others). It's got to do with the environment, preserving it, finding new alternative power sources, etc etc.. Not sure on the EXACT details, but pretty much, if aus signs it it would mean no more cole industry which would mean economic depression for the country... If also means that the country is doing our part to preserve/fix/maintain the environment i guess.
And not sure how its spelt kyoto/kyote whichever... It's something like that =/