27 September 2004 | EN
Jacques Descloitres/MODIS Rapid Response Team, NASA GSFC
Whether human activity should share any blame for the storms currently sweeping the Caribbean remains uncertain. What is not in doubt is that such activity has contributed significantly to the resulting devastation.
To describe the widespread destruction left last week by tropical storm Jeanne as it swept through Haiti as an accident waiting to happen would trivialise the latest human tragedy to hit the island. But as bodies continue to be recovered from mud and debris left behind by the flooding — more than 1,000 are already known to have died, and the final figure is likely to be much higher — many legitimate questions are being asked about what more can be done to limit the impact of such events in the future, and what science can contribute.
Whatever conflicting views may exist in the scientific community about the origins of the hurricanes that have been sweeping the region this year with a ferocity unknown for several decades, there is widespread belief that such events are likely to increase in the years ahead. Indeed a report published earlier this year by researchers at the United Nations University predicted that, unless preventative steps are taken, there will be a doubling of the number of people living in the path of devastating floods over the next 50 years (See Threat of devastating floods 'will double' by 2050).
As a result, addressing both the origins and consequences of weather-related disasters must remain high on the global research agenda in the years ahead. Awareness of this need already exists within the scientific and technological communities. It is clear, for example, that the impact of the recent storms would have been very much greater without the accurate forecasting techniques — the outcome of decades of research — that allowed many millions to escape their worst effects. The challenge is to find new ways of channelling scientific expertise into prevention strategies that still receive only a small proportion of the resources usually required to cover the resulting damage, not to mention the cost of the loss of human life.
Impact of deforestation
Deforestation and climate change were two of the factors identified in the UNU report (a third being population growth). The role of the first of these in Haiti is already evident. A country which, even half a century ago, was covered by large areas of forest has seen most of this disappear as wood during the intervening period, to the extent that trees now cover less than 1.5 per cent of the total land area. As a result, the water that fell on the island during last week's storms rapidly washed away much of the remaining soil and clogged the rivers with debris, destroying houses and communities in their wake.
As experts point out, deforestation is a complex process that has different origins in different parts of the world. In much of Latin America, for example, a major cause is the clearance of land for soyabean production, particularly to meet the growing demands for animal food in Europe and, especially, China. In Haiti, the driving force seems to have been poverty, which has forced people to rely on wood as a source not only of fuel — there is no electricity outside the major towns on the island — but also, through its sale as charcoal, of a meagre income.
The social cost of such practices was already made vividly clear by another heavy storm that hit both Haiti and the neighbouring Dominican Republic earlier this year (See Reforestation could prevent future floods in Haiti). In the latter, where much of the forests remain intact, the death toll was relatively minimal. In Haiti, in contrast, deforestation was largely blamed for the deaths of more than 3,000 in widespread flooding from which the country was only just beginning to recover when last week's events knocked it back on to its knees.
Technology may be able to reduce the pressure on trees, at least in the short and medium term. Scientists working for a group known as the Haitian Environmental Foundation, for example, are currently investigating alternatives to wood for cooking stoves, and have developed briquettes made out of compressed recycled paper that burn more efficiently and cleanly than charcoal. The foundation is also subsidising the conversion of ovens used in bakeries — among the largest consumers of wood in Haiti — to run on propane, while the US Agency for International Development has been replacing about 50,000 wood stoves a year with oil-fired burners.
But even those involved in such projects (and as well as complementary replanting programmes) admit that they can only scratch the surface of problems that have much deeper roots. And that technical fixes, however much they remove pressures on scarce resources, will only make an impact in the long-run if they can be integrated into sustainable development strategies that allow individuals to rise from the poverty that is itself the cause of so many unsustainable social practices around the world.
The need for a strategic approach
A piecemeal approach to weather modification is even less likely to have a significant impact. There has been no shortage of ingenious technical proposals. The most widely tested have been efforts to 'seed' rain clouds with silver iodide to accelerate the life cycle of cyclones by encouraging water to condense inside them. Pioneered in the United States, and now being considered in countries like China, such cloud-seeding techniques still hold some promise, even if initial experiments have been disappointing. But whether they would have any significant impact on the types of storms currently being encountered in the Caribbean remains highly uncertain.
The same is true of other, more ingenious, ideas. One that has been receiving some attention in Mexico and elsewhere has been to investigate ways of preventing the evaporation of ocean water in region where cyclones form. And in the 1970s, an alternative suggestion – so far untested – was to spread clouds of ash particles around the edges of the cyclone to generate heat by absorbing solar radiation, and thus reduce the power of the storm.
What is already clear, however, is that, as with deforestation, individual technical fixes, even if they eventually prove to have some effect, also have their limits. What is required is a strategic approach that places the efforts of individual teams of researchers within a wider context that seeks to address some of the underlying causes of problems. Which is where the question of climate change — and attempts to limit the phenomenon and to mitigate its consequences — comes in.
As with the extensive flooding caused in Bangladesh earlier this year (see Bangladesh floods: rich nations 'must share the blame'), there is no clear evidence that climate change can be identified as the main cause of the recent hurricanes and tropical storms in the Caribbean. Certainly, as residents of the region know only too well, there have been many similar, and frequently more devastating, events in the past. And the most recent ones could well be primarily due to natural geochemical cycles, including the warming of parts of the world's oceans.
But it would be equally shortsighted to deny that global warming could be involved in some way. As many have pointed out, the warming of the oceans (together with the subsequent rise in sea-level across the globe) is one of the most widely predicted components of global warming. And that itself means that, although curbing such warming is unlikely to reduce significantly the incidence of tropical storms, refusing to take major steps in this direction is likely to help increase both their frequency and severity.
In the past, hurricanes and cyclones were frequently referred to as 'acts of God', for which explanations were sought in human transgression, and avoidance through prayer and good behaviour. More recently, the tendency has been to label them as 'natural disasters', with the implication of inevitability, and the possibilities of human intervention limited to prediction and protection.
Both remain important priorities. And modern science can contribute substantially to each. The challenge now is to move beyond a primarily reactive mode to such disasters by recognising that they are increasingly due to a combination of natural and human causes — and that responses need to be moulded accordingly. One, for example, might be the creation of a new Global Disaster Management Agency. Others lie in ensuring that definitions of sustainable development include fully developed risk management strategies. There are no easy solutions. But it remains essential that we continue to look for them, at the scientific, technological and political levels.
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