John Rapley
IT IS no longer just religious millenarians and radical environmentalists who see natural disasters as a sort of punishment for human misbehaviour. Scientists, too, are growing mindful of the ways in which human activity can exacerbate or even precipitate natural disasters.
The trail cut by Katrina in the United States provides a painful illustration. Building a city in a basin is an obvious invitation to trouble. Add to that the gamble that a sufficiently powerful storm would not come along to overwhelm the city's inadequate system of dams, and you can see that humans are tempting fate.
But the most telling pictures of all remain those which we see on our television screens. The face of suffering in New Orleans has been overwhelmingly poor and black, reflecting the fact that natural disasters, like outbreaks of disease, are not as indiscriminate as they seem. They do the most damage in areas with poor infrastructure. In those areas, they tend to do the most damage to those with poor means. Thus, in a society like the U.S., which has a high per capita income but also a relatively high degree of income inequality, a storm like this will do more damage than it would elsewhere.
Meanwhile, some scholars argue that in other ways, human activity is producing more natural disasters. Certainly the news seems to be filled with a daily litany of tragedies, from tsunamis to floods to typhoons and droughts. And there is no question that this storm season is shaping up to be one of the busiest in a long time.
GREENHOUSE EFFECT
Global warming seems the obvious culprit. It has been suggested that industrial development, by raising the emission of greenhouse gases, is leading to a rise in the mean surface temperature of the planet. Greenhouse gases - namely, those associated with carbon emissions - create a denser atmosphere. By trapping the sun's rays as they bounce off the surface of the Earth, this so-called greenhouse effect leads to a build-up of heat on the planet.
This, in turn, is said to be creating a more volatile climate, with both harsher storms and longer droughts, a pattern which seems all too familiar here. But does the scientific evidence confirm this commonplace assessment? On that, the jury appears to be still out, though some clarity seems to be emerging. That the mean surface temperature of the planet is rising now seems incontestable. That, however, is not unusual. The planet's temperature goes through regular cycles of warming and cooling.
Nevertheless, most scientists now seem to agree that the rise of recent decades has gone beyond levels that could be described as purely cyclical. Accordingly, what is probably the most authoritative statement on the subject, put out four years ago by the Intergovernmental Panel on Climate Change, accepted that human activity was exacerbating global warming.
GLOBAL WARMING
But does global warming precipitate changes in the weather? Images of melting ice caps and surging storm waves seem to provide dramatic evidence that this should be the case. But in fact there is apparently not yet convincing evidence that a major change in the Earth's weat-her patterns has begun. From a Caribbean perspective, what this amounts to saying is that global warming has not precipitated an increase in the number of storms. This just happens to be a busy season.
Nevertheless, the story may not end there. While we may not be experiencing more storms, the intensity of those that occur does seem to be picking up. This appears to be because global warming, by raising rates of evaporation, is feeding more moisture into storm systems. Equally, rising sea temperatures channel greater energy upwards. Thus, higher winds, heavier rains and so greater flooding - of the sort seen in the U.S. - are to be expected.
A volatile nexus thus comes into view. First, human activity may create a natural environment which is potentially more threatening. Second, human activity may - in the political and economic systems it forms - create a physical environment which is more vulnerable to these threats.
This may well account for the terrible toll of Katrina. If so, it reveals that addressing climate change will require more than good science. It will require good politics, not to mention sound economics.
John Rapley is a Senior Lecturer in the Department of Government, Mona, UWI.
