LIKE OTHER FARMERS in Australia’s cropping belt, David Kreig was dismayed by the way the weather seemed to be continuing to get hotter and drier. In 1995, he bought a property north of Hay, in south-western New South Wales, a region whose climatic history suggested he could expect at least one heavy wet season by 2000. “Once, we could always rely on getting three floods each decade,” he says. “Ten years later, we haven’t had one.”

Many farmers facing Kreig’s problem have been forced either to adapt to Australia’s new climatic uncertainties or to walk off their land. His response is one that would have been unthinkable even a decade ago. In 2004, Kreig struck a deal with CO2 Australia, a Melbourne-based company, to plant rows of mallee trees between the wheat, barley and pea crops he grows on Ionavale, another property in the same region, near Griffith. The company is using the trees, or more strictly the carbon they absorb from the atmosphere, to sell as carbon credits to Origin Energy, an electricity supplier. Kreig receives a fee from CO2 Australia for using his land over the 30-year life of the trees’ carbon-absorbing cycle, plus a small share from the sale of the carbon credits.