It would not be surprising, however, if as seems to be the case Japan failed to take cost-justified measures to minimize the damage from a 9.0 or greater earthquake. Politicians have limited time horizons. If the annual probability of some catastrophe is 1 percent, and a politician’s horizon is 5 years, he will be reluctant to support significant expenditures to reduce the likelihood or magnitude of the catastrophe, because to do so would involve supporting either higher taxes or a reallocation of government expenditures from services that provide immediate benefits to constituents. In principle, it is true, politicians would take a long view if their constituents did out of concern for their children and grandchildren. But considering how the elderly cling to their social benefits, paid for by the young including their own young, I doubt the strength of that factor, although I do not know enough about Japanese politics to venture a guess on whether politicians’ truncated policy horizons was indeed a factor in Japan’s surprising lack of preparations for responding promptly and effectively to the kind of disaster that has occurred.
Now, my present understanding of the nuclear issue in Japan is simply that the ample backup systems weren't sufficiently tsunami-hardened; thus it was (on my current understanding) a design failure rather than an expenditure failure that accrues the risks, such as they were. But the question raised by Posner stands.
The motivations for long-range thinking and planning are structurally missing from our institutions. Indeed, they are not easy to build in, but one could at least imagine doing better somehow. As things stand, our obligation to future generations is entirely imposed by ethics, and this in an era in which cold calculation reduces ethics to brand reputation and little else.
Fixing this is not a matter of a tax on carbon; it goes much deeper than that. But how can we imagine a tax on carbon otherwise? Any policy which takes us away from disaster imposes almost pure and certain costs in the short term in exchange for (as it happens, highly likely, but even this is not universally recognized) benefits in the future, essentially beyond the political careers of present day politicians.
And it always will! No matter how bad climate impacts get, policy implemented in a given year will impose immediate costs at the expense of benefits delayed by decades.
This is why there is so much focus on secondary benefits of "green economy" etc. But this comes down to an argument about public sector investment vs pure market-based employment. It's really secondary whether the public sector investments are "green" or not. So in the end, however compelling the need for a green economy, it fails on purely economic grounds, because the future is systematically discounted.
Whenever calculations are reduced to money, long term prudence fails. And this, not the fundamental truth of the Malthusian argument, but its conditional truth in contemporary institutional settings, is what is driving us off the cliff.
Who speaks for the future?