Evaluating impact of surface ozone on mortality and crop yields over South Asia

English Abstract:

Climate change has been shown to increase surface O₃ in many regions of the world and have raised concerns about the O₃ impact on mortality and the magnitude of yield reductions, primarily occurring in the developing nations. Demographically agriculture is the broadest economic sector, rank worldwide second in farm output and principle source of livelihood for more than 58% of 1.2 billion populations which plays an important role in the overall socio-economic fabric of India. For the potential impact of ozone on district-wise cotton, soybeans, rice, and wheat crops in India for the first decade of the 21st century. Wheat is the most impacted crop with losses of 3.5±0.8 million tons (Mt), followed by rice at 2.1±0.8 Mt, with the losses concentrated in central and north India. On the national scale, this loss is about 9.2% of the cereals required every year (61.2 Mt) under the provision of the recently implemented National Food Security Bill by the Government of India. The nationally aggregated yield loss is sufficient to feed about 94 million people living below poverty line in India. Significant portion of human population in India is believed to be regularly exposed to higher surface ozone (O₃) levels. Here, we have also evaluate total, cardiovascular and respiratory mortalities and hospitalizations (COPD) caused by population exposure to surface O₃. Attributable mortalities are quantified using health impact function of long-term relative risk estimates (population attributable-risk proportion) for O₃ from epidemiology literature. We calculated total mortality of about 1125 thousands, 404 thousands by cardiovascular deceases and 176 thousands by respiratory deceases, and COPD cases of about 175 thousands caused by O₃ exposure to population of India in 2005. The highest number of total, cardiovascular and respiratory mortalities and COPD cases are found in the highly populated Indo-Gangetic region followed by metro-cities and sub-urban and industrial areas.