Carbon offsets have underpinned Australia's climate policies for the last decade. But the credibility of the carbon credits market has been tarnished with allegations of fraudulent credits, and questions over what constitutes a carbon offset, with one category called 'avoided deforestation' paying landholders not to clear trees they had permits to clear.So is the carbon market just another tool for greenwashing? Or a necessary step in the slow march to net zero?Jacob speaks with carbon-neutral farmer Mark Wootton, and environmental investigator from the Australian Conservation Foundation Annica Schoo. Earth Matters #1386 was produced by Jacob Gamble