Some aspects of global lightning impacts

A review of lightning impacts around the globe is made. The historically decreasing rates of population-weighted lightning-caused fatalities and injuries in the United States are examined over the last century. A similar reduction in lightning casualty rates has occurred in recent years in Canada, Western Europe, Japan, and Australia. Of relevance in these areas is the change from a mainly rural agricultural society to a primarily urban society. The first color-coded maps by continent of lightning fatality rate per million are shown based on 22 published national-scale studies for periods ending in 1979 and later. A significant aspect of the lower casualty rates has been the widespread availability of lightning-safe large buildings and fully-enclosed metal-topped vehicles, as well as much greater awareness of the lightning threat, better medical treatment, and availability of real-time lightning information through a variety of methods. However, lightning exposure in many lesser-developed countries is more similar to that of a century ago in the developed countries, and the population in these areas may be increasing, so the number of people killed and injured by lightning may be growing globally due to these socio-economic factors. With respect to exposure of infrastructure to lightning damages, including the interruption-sensitive power grid, it appears to be increasing in more developed countries, due to a high reliance on lightning-vulnerable electronic equipment and communications. Additional very large costs are incurred in prevention and avoidance techniques to reduce or mitigate lightning-caused disruptions. In lesser-developed countries, such disruptions to power supplies and communications are also growing. Lightning additionally causes forest and range fires in many areas of the world. These damages are difficult to quantify and are variable in time and area, but preventative activities and direct impacts cost billions of dollars per year.