This planisphere is an attempt to provide a synthetic map of natural and anthropogenic hazards which have become an everyday affair in tropical seas. Rarely a year or a month goes by without a disastrous flood, a destructive cyclone, a lethal tsunami or, albeit less frequently, an El Niño-type heat wave (see pp. 14-15) occurring in these areas.
More than half of all tropical seas are exposed to the threat of such “extreme events”. In addition, slow and irreversible destructive processes are also taking place (submersion and disappearance of islands – see pp. 12-13), due to the rise in sea levels and temperatures, the subsidence of coasts, etc.
As well as natural phenomena, anthropogenic impacts are also on the rise, from marine pollution, mechanical or chemical deterioration of coral reefs and the over-exploitation and collapse of fish stocks, to the ever-expanding floating “waste dump” and the toxic spread of atmospheric pollution from Asia. Other processes (receding mangroves, acidification of waters, rampant urbanisation, etc.) could not be shown at this scale.