Carbon offsets allow countries or companies to pay others to cut greenhouse gas emissions to offset their own. Countries applauded each other at last year's climate summit in Glasgow for agreeing on broad principles governing carbon markets, breaking six years of stalemate. Applying to join the new system without knowing what rules will govern it would be difficult, said Pedro Martins Barata, a carbon markets expert observing the talks for the non-profit Environmental Defense Fund. Voluntary carbon offset markets have struggled to gain trust for years. Reuters GraphicsPrivate initiatives like the Integrity Council for the Voluntary Carbon Market (ICVCM) and the Carbon Credit Quality Initiative (CCQI) have drafted guidance on what they see as a high-quality carbon offset.

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