With the Paris summit wrapping up having delivered an historic global climate agreement, questions will turn to whether Malcolm Turnbull will use the international momentum to advance the climate debate back home. 
For half a decade, Australia has been stuck in a fact-free debate on climate policy - one that has seen one of the biggest challenges the world faces turned into a domestic political chew toy.
But where the failure at Copenhagen helped derail Kevin Rudd's climate ambition in 2009, success in Paris presents the opposite opportunity for Turnbull, who many believe has a deep desire to move to a more robust climate policy.
The excuse presented for inaction for so long - that the world is not acting - no longer holds water. The deal in Paris is going to require Australia, and all countries, to take on more responsibility to meet its long-term goals.
For a start, Australia has to review its emissions targets. It has set what is widely regarded to be a low-ball goal of cutting emissions by 26 per cent to 28 per cent below 2005 levels by 2030. The government has known it may have to lift this under the Paris deal, and has been preparing for it by signalling it will allow the use of international carbon markets - representing cuts effectively in poorer countries paid for by Australia - from 2017.
Deeper cuts will also require a bigger re-think of domestic policies.
Australia will have to find a way to address pollution from the fleet of large, ageing coal-fired power plants.
The government's direct action scheme is not fit for this job. It will need a radical overhaul, perhaps one that would make it look more like a type of emissions trading scheme.
This is the kind of debate business has been crying out for.
How fast Turnbull can move, assuming he wants to, is an open question.