Carbon offsets too often don’t deliver. Inside the race to fix them.

They are marketed as a solution for companies and consumers looking to erase their carbon footprint, with promises that money spent on “offsets” will go to projects that mitigate greenhouse gas, like tree planting or land preservation.

But this global network of loosely monitored credits is in chaos. Lack of oversight, inadequate scientific review and faulty accounting have left the voluntary offset market awash in credits that studies conclude are not coming close to canceling out the level of emissions claimed, and often not erasing any.