In addition to being an expert on economic history, Thomas Piketty turns out to be an expert on atmospheric physics. One would think that an advocate of greater wealth equality would welcome a sea level rise sufficient to wash away all of the Wall Streeters’ houses in the Hamptons. Apparently not.
climate change and, more generally, the possibility of deterioration of humanity’s natural capital in the century ahead. If we take a global view, then this is clearly the world’s principal long-term worry. The Stern Report, published in 2006, calculated that the potential damage to the environment by the end of the century could amount, in some scenarios, to dozens of points of global GDP per year.
Piketty never explains why growing wealth inequality was the world’s #1 problem in the preceding 600 pages but climate change takes over the #1 spot for a short portion of the book.
Should we attack the problem now, when America’s best engineers can’t figure out how to deliver working WiFi service at brand new billion dollar airport terminals (see SFO, for example!)?
Nicholas Stern, who is British, argued for a relatively low discount rate, approximately the same as the growth rate (1–1.5 percent a year). With that assumption, present generations weigh future damage very heavily in their own calculations. William Nordhaus, an American, argued that one ought to choose a discount rate closer to the average return on capital (4–4.5 percent a year), a choice that makes future disasters seem much less worrisome.
For Stern, the loss of global well-being is so great that it justifies spending at least 5 points of global GDP a year right now to attempt to mitigate climate change in the future. For Nordhaus, such a large expenditure would be entirely unreasonable, because future generations will be richer and more productive than we are. They will find a way to cope, even if it means consuming less, which will in any case be less costly from the standpoint of universal well-being than making the kind of effort Stern envisions.
Stern’s opinion seems more reasonable to me than Nordhaus’s, whose optimism is attractive, to be sure, as well as opportunely consistent with the US strategy of unrestricted carbon emissions, but ultimately not very convincing.
Piketty proposes spending vast sums, though he admits that nobody has any idea what would be worth funding:
The public debt (which is much smaller than total private wealth and perhaps not really that difficult to eliminate) is not our major worry. The more urgent need is to increase our educational capital and prevent the degradation of our natural capital. This is a far more serious and difficult challenge, because climate change cannot be eliminated at the stroke of a pen (or with a tax on capital, which comes to the same thing). The key practical issue is the following. Suppose that Stern is approximately correct that there is good reason to spend the equivalent of 5 percent of global GDP annually to ward off an environmental catastrophe. Do we really know what we ought to invest in and how we should organize our effort? If we are talking about public investments of this magnitude, it is important to realize that this would represent public spending on a vast scale, far vaster than any previous public spending by the rich countries.
Should we count on advanced research to make rapid progress in developing renewable energy sources, or should we immediately subject ourselves to strict limits on hydrocarbon consumption? It would probably be wise to choose a balanced strategy that would make use of all available tools.55 So much for common sense. But the fact remains that no one knows for now how these challenges will be met or what role governments will play in preventing the degradation of our natural capital in the years ahead.
More: read Capital in the Twenty-First Century.