Latest study suggests that urban areas are more prone to frequent heat waves in comparison with other regions.
The latest study conducted by a team of researchers from the Indian Institute of Technology Gandhinagar (IITGN), University of California at Los Angeles, University of Washington and Northeastern University suggest that prolonged phases of extreme hot days have increased in more than 200 urban areas worldwide between 1973 and 2012.
The researchers suggest that the new study is one of the first that focuses mainly on the degree of extreme weather being experienced globally and it is one of the first that examines discrepancies between nonurban and urban areas.
The study collected daily observations regarding air wind speed, temperature and rain from the data created by the National Climatic Data Center. The researchers defined heat waves as periods when the maximum daily temperature was hotter in comparison to 99 percent of days for the period 1973 to 2012, for a consecutive period of six or more days.
The study found that about 50 percent of the cities witnessed a spike in the total number of extreme hot days. The researchers also found that almost 66 percent of the urban regions examined also frequently witnessed extreme hot nights.
The rate of extreme cold days also decreased during the same period. The total number of windy days also dropped down in around 60 percent of the urban areas. However, rainfall in 17 percent of the urban areas increased.
Vimal Mishra of IITGN revealed that it is important to understand these changing aspects of climatic conditions in urban areas, as a major chunk of the world's population resides in urban areas. Mishra also pointed out that by 2050 about 70 percent of the world's population is estimated to reside in urban areas.
"Urban areas are centers of wealth, and damages to urban infrastructure represent potentially large economic losses," says Mishra. "Nonetheless, there have been surprisingly few studies that have focused on changes in climatic extremes in these areas."
The researchers suggest that the study has important implications, especially for health departments in urban regions. The increased rate of heat waves may result in a jump in mortality related to heat waves.
The study also has deep implications for businesses and residents as an increase in heat waves may reduce demand for heating but increase the need for cooling in urban areas.
