What was agreed at COP24 in Poland and why did it take so long?

Fractious UN climate change talks ended with a deal on putting the Paris agreement into practice - but much else left unresolved

• 'We can move forward now': climate talks take significant step

Countries settled on most of the tricky elements of the "rulebook" for putting the 2015 Paris agreement into practice. This includes how governments will measure, report on and verify their emissions-cutting efforts, a key element because it ensures all countries are held to proper standards and will find it harder to wriggle out of their commitments.