Human activity is thought to exacrebate `natural` hazards in some situations. An example is the claim that logging and other forestry operations that leave the ground bare can result in worse flooding problems in surrounding areas. What mechanisms could a

Impact of Human Activities on Natural Hazards

Natural hazards are naturally occurring phenomena that have disastrous impact on humanity . These phenomena had been in existence even before the advent of humanity . The hazardous dimension of these natural phenomena are in the context of the impact that such a phenomenon would have on human population in the area affected by that phenomenon . In this essay , the effect that human activity has on these natural hazards would be analyzed . Some human activities may be exacerbating the factors that cause the natural hazard , like the

impact of excessive and unplanned logging on floods and droughts . In certain other cases the human activities may cause subsequent or supplementary hazards to a primary hazard event , like building dams in earthquake prone zones may lead to flash floods and landslides in the event of a rupture

A hazard can be defined as an event that has the potential to cause harm . This potential may be on account of its unexpected timing of occurrence or the actual intensity of the event itself . Human societies can withstand these events within a normal scale of occurrence . However human societies become vulnerable when these events occur unexpectedly or are of an intensity or duration that falls beyond that normal scale (O 'Hare and Rivas , 2005 . Natural hazards can be broadly classified under the heads of geological , hydrological , climatic and diseases . This essay would limit its scope to analyzing causal relationships , if any of human activities on landslides , floods and drought and the secondary hazards triggered by those activities in the event of an earthquake

Of all human activities that have a direct or indirect impact on natural hazards , deforestation is by far the most significant Deforestation is the removal or destruction of forest cover of an area It may occur due to unscientific logging practices without regeneration and may be accompanied by subsequent conversion to non-forest usage like agriculture , pasture , urban , mining or industrial development , fallow or wetland

At a very broad level , it has been argued that deforestation is a major cause of global climatic changes . It has been predicted that removal of forest cover will lead to violent and unpredictable environmental fluctuations . At a smaller landscape , deforestation has a direct bearing upon the climatic , hydrological , edaphic and biological aspects of that area . Deforestation is associated with higher levels of soil erosion and landslides , sedimentation in river beds and changes in fluvial geomorphology (Haigh , 1984 . Quite a few of these effects of deforestation have a direct bearing on the natural hazards that will be covered in this essay

One of the major functions of a forest is to maintain the humidity level in the atmosphere . Trees withdraw groundwater through their roots and transpire the excess water through their leaves . Forests return a major part of the rainfall received by them through evapotranspiration . Annual evapotranspiration in tropical moist lowland forests ranges up to 1500 mm per year , with transpiration accounting for a maximum of 1045 mm per year (Bruijnzeel , 1990...