There's no simple way. We've heard about a carbon tax. We've heard about a whole lot of other policies. But there is no simple way to put a price on the tailpipe of your car, on the emissions from the steel mill, the emissions from the cement kiln at Portland in Whangārei, or the pulp and paper mills, or even the emissions from that wonderful Huntly power station, which generates a fantastic thermal baseload of energy and keeps the lights on in the North Island, particularly in winter when it's dry—and, potentially, in summer in the future, where Aucklanders and those in Hamilton and other parts of the country will want to use their heat pumps as air conditioners. Because that's what progress is: progress is using technology that we thought we might use for one thing—a heat pump to keep us warm in winter. It actually turns out we might like to keep the doors closed and run an air con unit in summer, because it's much more comfortable watching the cricket and being nice and cool inside than having a blast of heat. 