A giant natural-gas operation that Shell Oil is building in Qatar will disrupt birds and rare desert truffles — but the company plans to make amends by protecting antelopes, turtles, and sea cows elsewhere in the emirate. Such “biodiversity offset” schemes are up-and-coming, as companies seeking to burnish their eco-reputations come together with conservation groups increasingly willing to work within market-style systems. Mining company Rio Tinto is making efforts to attract flora and fauna to land it’s no longer using, creating “a biodiversity buffer” that, according to CEO Tom Albanese, “also could be used to create the next generation of green credits.” Indeed, some envision companies eventually trading such credits like they trade carbon-emission permits. While some conservationists applaud such schemes, others cry greenwash. “Offsets are actually a zero-sum game,” says environmental-policy professor Richard Steiner. “Eventually, there will be nothing left with which to offset anything — what then?”