Nature: With just six months left to go, all sectors are vying for a place at the table in Copenhagen, where negotiators will begin sketching what should eventually become an all-embracing climate deal. While some players are seeking assistance in adapting to the impacts of climate change (page 68), others are hoping to stake a claim in the emerging green economy (page 72). The prospects of the latter are bright for those involved in the nascent biochar industry, which plans to sequester vast …