A decade earlier, South Pole had signed a deal to sell carbon offsets from an effort to protect a vast swath of forest on the banks of Lake Kariba, upriver from the camp. The Kariba project, spanning an area ten times the size of New York City, was among the world’s first “avoided deforestation” programs; by deterring local people from chopping down trees, it promised to prevent the release of tens of millions of tons of greenhouse gas.

Leading corporations, including Volkswagen, Gucci, Nestlé, Porsche, and Delta Air Lines, paid South Pole nearly a hundred million dollars for Kariba credits, allowing them to market goods or services as “carbon neutral.

This perspective was enthusiastically received: Heuberger had regular speaking engagements at Davos and a spot in the World Economic Forum’s network of experts. As brands scrambled for inexpensive ways to reduce emissions, the market for offsets surged, quadrupling in 2021 alone. That year, South Pole was approaching a billion-dollar valuation, which would make it the world’s first “carbon unicorn.”