EARTH SCIENCE, DISASTERS, AND THE PRECAUTIONARY PRINCIPLE

Earth science is arguably unique among sciences in its grounding in time, the fourth dimension. Today, however, nearly all societies operate almost exclusively in the present; most people's perception of “deep time” is at most a few decades. This view of time leads to reactive responses rather than proactive planning and contributes to many of the fundamental problems that beset humanity. Earth scientists must inform the public of the dangers of seeing the world only in the present. No one can foresee the future, but earth scientists can posit plausible natural events that are very low risk on short timescales, but extraordinarily high risk on timescales of centuries. Examples of such plausible worst-case scenarios include a global pandemic, sea-level rise of several metres, eruption of Vesuvius comparable to that in AD 79, a Category 4 hurricane making landfall in New York, and a great earthquake in Tokyo or Los Angeles. An appreciation of the inevitability of worst-case events plays on earth science strengths, because it demands that governments view their actions on timescales much longer than they have in the past. It further demands that we embrace the precautionary principle by preparing for natural disasters and catastrophes. Earth scientists will have to counter two arguments that delay proper consideration of catastrophic events in serious long-term planning – first, catastrophic events like the 2004 South Asian tsunami are so rare that we need not worry about them; and second, catastrophes are acts of God over which humans have no control. An example of an important issue to which earth scientists must contribute is the question of what, if anything, to do about global warming. We cannot predict exactly how increasing atmospheric CO2 concentrations will play out during this century, but the worst-case scenario, which is not ruled out by recent research, involves temperature increases of many degrees, sea-level rise of several metres, and catastrophic ecosystem damage. Earth scientists should not be fear mongers, but they must use their knowledge and skills to convince the public to at least consider what may seem unimaginable, worst-case scenarios.