M. Monirul Qader Mirza

Climate change and extreme weather events: can developing countries adapt?

Developing countries are vulnerable to extremes of normal climatic variability, and climate change is likely to increase the frequency and magnitude of some extreme weather events and disasters. Adaptation to climate change is dependent on current adaptive capacity and the development models that are being pursued by developing countries. Various frameworks are available for vulnerability and adaptation (V&A) assessments, and they have both advantages and limitations. Investments in developing countries are more focused on recovery from a disaster than on the creation of adaptive capacity. Extreme climatic events create a spiral of debt burden on developing countries. Increased capacity to manage extreme weather events can reduce the magnitude of economic, social and human damage and eventually, investments, in terms of borrowing money from the lending agencies. Vulnerability to extreme weather events, disaster management and adaptation must be part of long-term sustainable development planning in developing countries. Lending agencies and donors need to reform their investment policies in developing countries to focus more on capacity building instead of just investing in recovery operations and infrastructure development.

Global warming and changes in the probability of occurrence of floods in Bangladesh and implications

Abstract Bangladesh is very prone to flooding due to its location at the confluence of the Ganges, Brahmaputra and Meghna (GBM) rivers and because of the hydro-meteorological and topographical characteristics of the basins in which it is situated. On average, annual floods inundate 20.5 per cent area of the country and this can reach as high as about 70 per cent during an extreme flood event. Floods cause serious damage to the economy of Bangladesh, a country with a low per capita income. Global warming caused by the enhanced greenhouse effect is likely to have significant effects on the hydrology and water resources of the GBM basins and might ultimately lead to more serious floods in Bangladesh. The use of climate change scenarios from four general circulation models as input into hydrological models demonstrates substantial increases in mean peak discharges in the GBM rivers. These changes may lead to changes in the occurrence of flooding with certain magnitude. Extreme flooding events will create a number of implications for agriculture, flood control and infrastructure in Bangladesh.

The Implications of Climate Change on Floods of the Ganges, Brahmaputra and Meghna Rivers in Bangladesh

Climate change in the future would have implications for river discharges in Bangladesh. In this article, possible changes in the magnitude, extent and depth of floods of the Ganges, Brahmaputra and Meghna (GBM) rivers in Bangladesh were assessed using a sequence of empirical models and the MIKE11-GIS hydrodynamic model. Climate change scenarios were constructed from the results of four General Circulation Models (GCMs) –CSIRO9, UKTR, GFDL and LLNL, which demonstrate a range of uncertainties. Changes in magnitude, depth and extent of flood discharge vary considerably between the GCMs. Future changes in the peak discharge of the Ganges River are expected to be higher than those for the Brahmaputra River. Peak discharge of the Meghna River may also increase considerably. As a result, significant changes in the spatial extent and depths of inundation in Bangladesh may occur. Faster changes in inundation are expected at low temperature increases than of higher temperature changes. Changes in land inundation categories may introduce substantial changes in rice agriculture and cropping patterns in Bangladesh. Reduction of increased flood hazard due to climate change requires strengthening of flood management policies and adaptation measures in Bangladesh.

Are floods getting worse in the Ganges, Brahmaputra and Meghna basins?

The Ganges, Brahmaputra and Meghna/Barak rivers are lifelines for millions of people in South Asia in Nepal, India, Bhutan and Bangladesh. They supply water for food and fibre production and for industrial and domestic purposes. They are also sources of disastrous floods that cause substantial damage to agriculture and infrastructure in these countries. There are claims that flood discharges, areal extent, and damage-costs are getting worse in the Ganges, Brahmaputra and Meghna/Barak basins. The validity of these claims was examined by applying four different statistical tests to the peak discharge time series and flooded areas. The results indicate that no conclusive changes have occurred over the last few decades. Reports of increased flood damage may be due to a combination of other factors, such as improved damage assessment techniques, and the expansion and intensification of settlement in flood-prone areas, but this was not tested in this paper and should be top priority for future research.

Three Recent Extreme Floods in Bangladesh: A Hydro-Meteorological Analysis

Bangladesh is highly vulnerableto floods due to its geographical location at the deltas of the Ganges, Brahmaputra and Meghna (GBM) rivers. About 92.5 per cent of the area of three basins lies outside the boundaries of the country. More than 80 per cent of the annual precipitation of Bangladesh occurs in the monsoon period between June and September. The hydro-meteorological characteristics of the three river basins are unique and they often cause large to extremely large floods in Bangladesh. It is possible that these floods could inundate 70 per cent of the country and the physical damage could be very serious for the economy of Bangladesh with its low gross domestic product (GDP). In 1987, 1988 and 1998, Bangladesh experienced three extreme floods, leaving trails of devastation and human misery. In this article it is demonstrated that these floods differed in terms of magnitude, extent, depth and duration. The external and internal hydro-meteorological dynamics were also different.

Effects on Water Salinity in Bangladesh

The diversion of Ganges water in India by the Farakka Barrage and other engineering structures has resulted significant changes in the hydrology of the Ganges River system in Bangladesh. The system is comprised of the main Ganges River; the Mahananda, an important tributary; and the Mathabanga and Gorai, two distributaries. The analysis of discharge data of the Ganges and Gorai Rivers discussed in Chapter 2 demonstrate a significant reduction of water supply in the dry season and a considerable increase in the monsoon. Reduction in dry season discharge in the Ganges system in Bangladesh has generated a series of hydro-environmental implications.

The Ganges Water Diversion: Environmental Effects and Implications — An Introduction

Water is the most powerful agent in shaping the earth’s surface through the processes of rivers, glaciers, ground water, weathering, mass movement, and oceans. Water is also an important element that played a pivotal role in the development of the world’s civilizations. Since the dawn of civilization, humans have harnessed water in many different ways for their physical existence and the sustenance of the environment. They have devised ways of capturing, storing, purifying, and diverting freshwater resources to reduce their vulnerability to highly variable river flows and precipitation. Early agricultural civilizations developed in regions where precipitation and river flows were abundant and could be easily and reliably harnessed. Humans extended their river water-based transportation systems to sea travel and trade. With the growing need of goods, commodities and a safer environment, humans altered the natural hydrological cycle through massive engineering projects for water diversion, flood control, urban and rural water supply, hydropower, navigation and irrigation. The development of water resources served human societies in many positive ways as well as generated adverse effects. This book presents an analytical account of the effects caused by water diversions by major engineering works such as barrages1 and other structures built on the Ganges River (Figure 1.1) in South Asia.

Adverse Effects on Agriculture in the Ganges Basin in Bangladesh

The Ganges basin in Bangladesh has a humid climate, but it is vulnerable to drought in the summer as well as during the monsoon months. Mean annual rainfall ranges from 1,270 mm in the Western part of Raj shahi to about 3,000 mm in the coastal region in the South, meaning that the climate of the Western Ganges basin is naturally unfavorable for agriculture. Agricultural activities are largely dependent on the water supply from the Ganges River and its distributaries. The Ganges-Kobadak (G-K) project (Figure 9.1 and Box 9.1), one of the country’s largest surface water irrigation projects based on the water supply from the Ganges River was planned in the 1950s.

Interlinking of Rivers in India : Issues and Concerns

* Interlinking Rivers in India: Issues and Concerns * Interlinking of Rivers: Experience from Across the World * The Vital Link * The Interlinking of Indian Rivers: Questions on the Scientific, Economic and Environmental Dimensions of the Proposal * A Systems Approach to Interlinking Rivers in India: An Examination of Viability * Impact of the Interlinking of Rivers on Nepal: A Critical Analysis * Modeling the Interlinking of the Ganges River: Simulated Changes in Flow * Indias Energy Future and Interlinking of Rivers * Potential Public Health Implications of Interlinking of Rivers in India * Living in the Downstream: Development in Peril * Assessment of the Indias River Linking Plan: A Closer Look at the Ken-Betwa Link * Implications of Climate Change in South Asia on Interlinking Project of Indian Rivers * Interlinking of Rivers in India: International and Regional Legal Aspects * The Indigenous Knowledge Systems of Water Management in India * Water-Based Cooperation in the GBM Region with Particular Focus on Interlinking of Rivers in India * Could Bangladesh Benefit from the River Interlinking Project? * Hydrological Impact on Bangladesh of Chinese and Indian Plans on the Brahmaputra.

The Ganges Water-Sharing Treaty: Risk Analysis of the Negotiated Discharge

Sharing of the Ganges water was a subject of bilateral dispute between Bangladesh and India for more than three decades. Before the emergence of Bangladesh in 1971 as an independent nation, Pakistan and India wrangled over it for 20 years. The sharing problem seriously arose in 1974 when India had completed a barrage on the Ganges River at Farakka (18 km from the West border of Bangladesh) to divert 1,134 m3/sec of water to the Hooghly-Bhagirathi River, in order to make the port of Kolkata navigable by flushing down the silt that deposited over the centuries in the riverbed (Figure 13.1) (for details see Chapter 1). It was discussed at a meeting Head of the States of India and Bangladesh in 1974 (Abbas A.T., 1982).