India, April 24 -- For years, the global carbon market has been built on a simple premise that a tonne of carbon reduced or removed in one part of the world can compensate for emissions elsewhere. It is an idea that unlocked billions in climate finance and brought private capital into the fight against climate change. But today, that premise is under strain.

The question is no longer whether carbon markets can scale. It is whether they can be trusted.

This moment of reckoning has been building for some time. Investigations into over-credited projects, concerns around weak baselines and growing accusations of greenwashing have all contributed to a credibility gap. For many observers, the issue is not just technical, it is existential. If...