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Reg Environ Change (2011) 11 (Suppl 1):S95S107 DOI 10.1007/s10113-010-0184-7
ORIGINAL ARTICLE
Climate change, ooding in South Asia and implications
M. Monirul Qader Mirza
Accepted: 9 November 2010 / Published online: 3 December 2010 Her Majesty the Queen in Rights of Canada 2010
Abstract South Asia is one of the most ood vulnerable regions in the world. Floods occur often in the region triggered by heavy monsoon precipitation and can cause enormous damages to lives, property, crops and infrastructure. The frequency of extreme oods is on the rise in Bangladesh, India and Pakistan. Past extreme oods fall within the range of climate variability but frequency, magnitude and extent ooding may increase in South Asia in future due to climate change. Flood risk is sensitive to different levels of warming. For example, in Bangladesh, analysis shows that most of the expected changes in ood depth and extent would occur between 0 and 2 C warming.
The three major rivers Ganges, Brahmaputra and Meghna/ Barak will play similar roles in future ooding regimes as they are doing presently. Increases in future ooding can cause extensive damage to rice crops in the monsoon. This may have implications for food security especially of poor women and children. Floods can also impact public health in the ood plains and in the coastal areas.
Keywords Climate change Flooding South Asia Crop
damage Food security
Introduction
From a hydro-meteorological perspective, South Asia is a very important region in the world. It encompasses many
large river systems: Ganges, Brahmaputra, Meghna, Indus, Godavari, Mahanadi and Narmada (Fig. 1). Water availability in this region is driven by monsoons. Two monsoon systems operate in South Asia: the Southwest or summer monsoon and the northwest or winter monsoon. The summer monsoon accounts for 7080% of the annual rainfall over most of South Asia during June to September, except for Sri Lanka and Maldives where the northeast monsoon is dominant. Apart from the monsoons, the northern part of South Asia receives considerable precipitation from Western disturbances, and in the Southern parts (especially in Sri Lanka), from weather associated with the ITCZ (Inter-Tropical Convergence Zone). The Himalayan Rivers receive water from snow and glacier melt and have continuous ow throughout the year.
Flooding is a regular hazard in South Asia...