It's 7% of emissions caused by fossil fuels, not 7% of the fuels: coal is the worst of them.
Australia's emissions are smaller, however they enable much larger emissions elsewhere. Without that coal, India and China would be accelerating their transition to renewables.
Which is still not the same thing as 7% of global greenhouse emissions. Plenty of non-fossil fuel sources for emissions, like burning trees, cows making methane, etc.
Even if Australia were responsible for 7% of global greenhouse emissions, ceasing wouldn't be enough.