Can the carbon-offset market be saved?

“As soon asEU a coin in the coffer rings, the soul from purgatory springs,” ran an early advertising jingle attributed to Johann Tetzel, a 16th-century indulgence salesman. Funding the church offered believers an alternative to paying for sins in the afterlife. The carbon-credit market promises something similar. Instead of reducing your carbon footprint, why not simply pay someone else to do it for you?It is a nice idea. Yet the voluntary carbon market—as opposed to compliance markets, such as the ’s emissions-trading scheme—is in turmoil. Latter-day Martin Luthers, whose objections to Tetzel led to the Reformation, have pointed out that offsets struggle to prove they make a difference to emissions: renewable projects are often viable on their own, thus providing funding does not lower emissions.