Natural Liabilities
Factories produce the goods that we want. They also spew out smoke. The smoky factory is, in fact, the classic image used by economists to illustrate the idea of an externality. The factory sells the goods but does not have to pay for the smoke. We now know that smoke is more damaging than previously appreciated. There is nothing more natural than carbon dioxide; it is one of the basic ingredients of life. Yet carbon has become a natural liability. It accumulates up in the atmosphere, trapping in heat. Of course carbon only becomes a problem when it passes the threshold at which it is excessive. We have passed that threshold. As the extra carbon traps in heat, the world heats up, and as it heats up the climate becomes more volatile. The consequences are wide-ranging, but Africa will be the region most severely affected. Africa is huge and climate change will not affect it uniformly, but it seems likely that the drier parts will become drier still, making staple foods unviable. Increased climate variation, which means droughts, floods, and bouts of intense heat, can wreak havoc with traditional cultivation. Agriculture, which is currently Africa’s main economic activity, will become less productive. A rapidly growing population will be scratching a living from a progressively less amenable natural environment. Carbon brings together the key themes of this book. Although it is natural, extra carbon is now a liability; there is nothing intrinsically benign about nature. It is emitted not just by industry but by a number of natural processes. For example, probably the most natural of all human economic activities is rearing cattle. Pastoralists have been ranging the wilderness for millennia. Unfortunately, in terms of global warming, they are more of a menace than nuclear power stations, which produce energy without emitting carbon. That is because cows fart. Being renewable, carbon shares much of the economics of fish and trees, except that instead of being a renewable natural asset it is a renewable natural liability. The damage it does depends not upon how much is emitted today, but on how much has been emitted cumulatively over recent decades.