China has used up too much energy and too many resources in its quest for growth, Premier Li Keqiang has told visiting French President Francois Hollande, adding it has a "duty to humanity" to clean itself up.
Li's comments on Tuesday (local time) come ahead of a UN climate summit in Paris, which will seek to unite all the world's nations in a single agreement on tackling climate change.
Hollande said in a radio interview the summit's success was "possible, not certain", with some issues still to be settled.
As the world's largest polluter, China will be a key player at the event, in the face of disputes over whether developed or developing countries should bear more of the burden for reducing emissions.
Li said more environmentally friendly development would be "obligatory" for China to "promote a restructuring of its national economy", currently experiencing its slowest growth in years.
The shift was China's "duty and a contribution to humanity" as one of the world's largest countries, he added.
China's decades-long boom, which has propelled it to global prominence, largely depended on heavy industry, real estate and infrastructure investment. But growth has slowed in recent years and now stands at its lowest since the global financial crisis, according to official figures.
"For a great many years, we consumed too much energy and resources to achieve our development, and this model has since become unsustainable," Li said, adding that China must now rely more on developing its human resources.
But he did not cite any specific measures it would take.
On Monday China and France issued a joint declaration on climate change saying that the Paris accord – intended to cap warming at 2degC over pre-Industrial Revolution levels – should include checks for compliance.