Report warns of substantially reduced flow in Indian rivers in lean season and acute food scarcity if heat is not turned down
The unpredictability of Indian monsoons will increase further if the global rise in temperature is not controlled immediately. The frequency of extreme wet monsoon, currently witnessed in Uttarakhand and Himachal Pradesh, will also increase substantially. The water situation in river basins, especially that of the Ganga, will become erratic – there will be more runoff, that is more water flowing in the river, but wet seasons will become wetter and dry seasons drier. By the 2050s, with a temperature increase of 2°C-2.5°C compared to pre-industrial levels, water for agricultural production in the river basins of the Indus, the Ganges and the Brahmaputra will reduce substantially, impacting food adequacy for nearly 63 million people.
The analysis is part of a report by the World Bank titled Turn Down The Heat: Climate Extremes, Regional Impacts and the Case for Resilience, released on Wednesday. It looks at the likely impacts of 2°C and 4°C warming on agricultural production, water resources, coastal ecosystems and cities across South Asia, Sub-Saharan Africa, and South East Asia. It builds on a 2012 Bank report that concluded the world would warm by 4°C above pre-industrial levels by the end of this century if countries do not take concerted action now.
| Extreme impacts
- An extreme wet monsoon that currently has a chance of occurring only once in 100 years is projected to occur every 10 years by the end of the century
- Kolkata and Mumbai are ‘potential impact hot spots’ threatened by extreme river floods, more intense tropical cyclones, rising sea levels and very high temperatures
- Significant reduction in crop yields predicted. Some 63 million people may no longer be able to meet their calorific demand
- Substantial reduction in the flow of the rivers in late spring and summer
The report notes that the water available and flowing in the rivers will increase due to change in patterns of rainfall and melting of glaciers. However, this is not necessarily an indication of more water availability for water security. The changes will mean more water during wet season and lesser water than today during dry season. This will require huge investments for storing water for all purposes. “For such basins as the Ganges, another reason to strengthen water management capacities is that hydrological projections for the Indian monsoon region are particularly uncertain because of the inability of most climate models to simulate accurately the Indian monsoon,” states the report indicating that the human capacity to predict Indian monsoons is still abysmally low.
Kolkata, Mumbai, potential hot spots
The report, prepared for the World Bank by the Potsdam Institute for Climate Impact Research and Climate Analytics, says the consequences for South Asia of a warming climate are even worse if global temperatures increased by an average of 4°C by 2090. In this scenario, seen as likely unless action is taken now to limit carbon emissions, South Asia would suffer more extreme droughts and floods, rising sea levels, melting glaciers, and declines in food production. In India, for example, an extreme wet monsoon that currently has a chance of occurring only once in 100 years is projected to occur every 10 years by the end of the century.
The new report warns that by the 2040s, India will see a significant reduction in crop yields because of extreme heat. Reduced water availability due to changes in precipitation levels and falling groundwater tables are likely to aggravate the situation. In India, groundwater resources are already at a critical level and about 15 per cent of the country’s groundwater tables are overexploited.
Cities of Kolkata and Mumbai are “potential impact hot spots” threatened by extreme river floods, more intense tropical cyclones, rising sea levels and very high temperatures.
Measures to be taken
“The future that scientists have envisioned in this report reinforces the fact that climate change hits the poor the hardest and that it could roll back decades of development gains in India. In order to minimise the impacts of a changing climate, we need to ensure that our cities become climate resilient, that we develop climate-smart agriculture practices, and find innovative ways to improve both energy efficiency and the performance of renewable energies,” said Onno Ruhl, World Bank Country Director in India.
Under 2°C warming by the 2040s, crop production in South Asia may reduce by at least 12 per cent, requiring more than twice the imports to meet per capita demand than is required without climate change. Decreasing food availability can also lead to significant health problems, including childhood stunting, which is projected to increase by 35 per cent by 2050 compared to a scenario without climate change.
The changing climate will adversely impact forests in India even though Asia as a continent is at lower risk than the American continent. “In general, Asia is substantially less at risk of forest loss than the tropical Americas. However, even at 2°C, the forest in the Indo-China peninsula will be at risk of die-back. At 4°C, the area of concern grows to include central Sumatra, Sulawesi, India and the Philippines, where up to 30 per cent of the total humid tropical forest niche could be threatened by forest retreat,” notes the report.
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