It remains the case that many of the world's largest companies and their financial backers pay scant, by which I really mean no, attention to the deforestation footprint of their supply chains."

- Britain's Prince Charles, to COP21 delegates

"It's back to the nitty gritty"

With encouragement from 150 world leaders ringing in their ears, government negotiators in Paris sought on Tuesday to turn that rhetoric of unity into the text of a global deal to slow climate change.

But as the leaders departed Paris, it became apparent that disagreements which have blocked a deal over four years of lead-up negotiations remain unresolved.

Negotiators from the 195 countries with a place at the table resumed work on a draft text that still runs to more than 50 pages and is riddled with sticky issues to be settled.

The biggest obstacle is money: how to come up with the billions of dollars developing nations need to shift from fossil fuels and adapt to the impacts of climate change.

At Tuesday's technical talks, countries restated their well-known negotiating positions on the question with few hints of compromise.

China's delegate Su Wei "noted with concern" what he called a lack of commitment by the rich to make deep cuts in greenhouse gas emissions and help developing nations with new finance to tackle global warming.

And the group of the 48 least developed countries urged far tougher action to limit rising temperatures.

"It's back to the nitty gritty," said Alden Meyer, of the Union of Concerned Scientists, adding the opening day was "all good but that does not resolve the crunch issues."

Read full story - After leaders' rhetoric, climate negotiators start work on deal