The failure of carbon offsets to cut planet-heating pollution is “not due to a few bad apples”, a review paper has found, but down to deep-seated systemic problems that incremental change will not solve. Research over two decades has found “intractable” problems that have made carbon credits in most big programmes poor quality. While the industry and diplomats have made efforts to improve the system, it found much-awaited rules agreed at a UN climate summit last year “did not substantially address the quality problem”. “We must stop expecting carbon offsetting to work at scale,” said Stephen Lezak, at the University of Oxford’s Smith School. …In theory, the practice could lead to lower levels of global heating by funnelling money to the places where it will do the most good as soon as possible. But voluntary carbon markets have long been plagued by “junk offsets” that overstate their impact.