Monirul Q. Mirza & Ajaya Dixit :
The Intergovernmental Panel on Climate Change (IPCC) 6th Assessment Report (AR6) on climate change science asserts that human actions are the reasons for climate change and that it will make weather events more erratic, abrupt and extreme. In this write-up we have critically examined relevance of the IPCC AR6 findings and possible implications for the South Asian Region, the abode for approximately 1.85 billion people. In other words, one in every five-world population lives here. The region is characterized by differential climatic zones from the Himalayas to the coasts of the Bay of Bengal, Arabian Sea, and the Indian Ocean. Extreme weather events-heavy precipitation, heatwaves, droughts, cyclonic storms and coastal inundation, forest fire, etc. occur frequently in the region. These events lead to floods and droughts and regularly inflict heavy wounds to the life and livelihoods of the vulnerable population, ecosystems, and the economies. Approximately 81 percent of the population, are exposed to at least one form of natural hazard and live-in places with insufficient resources to cope with and recover from the impacts of catastrophic events.
Monsoon dominates life, livelihoods, and agriculture in South Asia. The evolution of cropping season and cropping pattern took place around onset and departure of monsoon which vary from year to year. The amount of precipitation also varies temporally and spatially. The spatial variation in precipitation amount occurs from the east to west. Hills and mountains have effect on the amount of precipitation but there are exceptions. Another important aspect of the monsoon is “break monsoon phase” In this phase the monsoon trough shifts close to the Himalayan foothills and stays there for two to three days leading to high rainfall around the trough while there is sharp decline in rainfall south of the trough, northeast India, and parts of the southern peninsula. The IPCC AR6 expresses high confidence in increase in mean precipitation and intensification of monsoon extremes over India and South Asia for both 1.5oC and 2oC global mean temperature rise. In general, for each degree rise in temperature, precipitation could increase by 6-7% due to availability of higher amount of moisture. AR6, however, does not address “break monsoon” issue under future climate change.
The intensification of heavy precipitation has major implications for South Asia. A large part of the region is vulnerable to floods that bring destruction to agriculture, infrastructure, industry and people with enormous impacts on poor marginal farmers and agriculture labour force. Not only frequent floods push people in the borderline of poverty to below it, they also affect GDP. An extreme flood could inundate 70% of Bangladesh for up to 68 days. Historical records show, Bangladesh’s GDP growth had suffered significantly during extreme flood years. In the mountainous regions of Nepal, Bhutan, India and Bangladesh, heavy precipitation triggers landslides resulting in destruction and deaths.
With climate change, there is a high probability of increased episodes of landslides and loss of human lives in the future. Urban flooding has already become a serious problem in the South Asian cities especially in the large ones. Flooding in Chennai, Karachi, Dhaka and Mumbai are annually in the news headlines. Presently more and more people are moving to urban areas and it is likely that by 2030, 55% of the population in Asia will live in cities, and urban areas will become hotspot of air pollution, floods and increased heat. The projected heavy precipitation as highlighted by the IPCC AR6 could translate into extreme urban floods unless proper flood risk management measures are put in place. The social and economic cost of urban flood will increase significantly.
Droughts and heatwaves are very common hazards in South Asia. Two third of India is chronically and frequently drought prone. Large parts of Pakistan in the south-west and east are moderately to severely vulnerable to drought. Considerable area of Bangladesh in the north-west and south is prone to very severe to severe droughts. As most of the agriculture land is still rain-fed, crop and livestock agriculture suffer greatly during a prolonged drought that could lead to food insecurity. In 1979, a prolonged drought had pushed Bangladesh almost on the brink of a famine. In a recently released report, the UN has estimated that impact of severe droughts on India’s GDP to be about 2-5%.
The plains of South Asia are hot in summer, heatwaves are common and a significant number of people die from this extreme hazard. Although IPCC AR6 is in low agreement on agricultural and ecological drought in South Asia in the future, extreme heatwaves for a prolonged period would increase irrigation water demand as evaporation increases. Heatwaves and humid heat stress would cause serious health problems for the elderly and child population. Agriculture labor force exposed to outdoor weather will suffer.
(Monirul Q. Mirza is an Adjunct Professor at University of Toronto Scarborough, Canada and an IPCC Author and Ajaya Dixit is Senior Advisor of Kathmandu based
ISET Nepal).
— To be Continued.
