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Extreme Weather Events in a Changing Climate

 

extreme

This World Bank research on extreme weather events focuses on potential impacts of floods and cyclones on population and economic productivity, and quantification of adaptation costs.

Contact: Susmita Dasgupta, sdasgupta@worldbank.org

 

Monsoon flood  | Cyclone |  Presentations | Researchers | Research outputs 


Global warming may have severe consequences for developing countries prone to extreme weather events

Projections by the Intergovernmental Panel on Climate Change and the World Meteorological Organization indicate an increase in the frequencies and/or intensity of climate extremes in the 21st century. Some recent extreme weather events illustrate how severe the consequences of these events can be.

Examples include heavy floods in Australia and Brazil in 2011; the heat wave in Russia in 2010; devastating floods in Pakistan, India, China, and Mozambique in 2010; and super cyclones in Myanmar in 2008 and Bangladesh in 2007.

Adaptation to increased risks of severe weather events, as well as other impacts of climate change, is essential for development

Adaptation will require climate-smart policies and investments to make countries more resilient to the effects of climate change, including losses of property, habitat, infrastructure, and lives. Governments and their citizens, as well as development partner institutions and climate negotiators, need a better understanding of potential damage due to climate change and adaptation costs to formulate effective adaptation to extreme weather events.

 
Monsoon flood 
 

The Intergovernmental Panel on Climate Change, in its overview of global trends for extreme weather events, has noted that the frequency of heavy precipitation events has increased over most land areas. Flood-related deaths in developing countries rose steadily from 17,000 in the 1960s to over 58,000 in the 1990s. This increase reflects increases in vulnerability (such as larger populations in flood-prone areas) as well as the increased occurrence of extreme precipitation events.

Aside from those killed, floods affected billions of people who were injured, made homeless, or forced to seek emergency assistance. Recent examples of extreme precipitation impacts in developing countries include: floods in Pakistan (1,600 death and 14 million people displaced in July 2010), India (1.1 million people displaced in July 2010), China (300,000 people displaced in Hubei, Sichuan, and Shaanxi provinces in May 2010; 4.7 million people displaced in Southern China in July 2010); and Mozambique (130,000 people displaced in February 2010). More intense and unpredictable precipitation events are expected in a changing climate. The magnitude of more intense precipitation events could in some cases be catastrophic for densely populated areas. Currently, systematic studies of future climate patterns, location-specific impacts, and cost of adaptation are scarce in developing countries.

  • Kolkata, India. One part of this research assesses the consequences of climate change for flooding of Kolkata, a heavily urbanized megacity, with high resolution spatial analysis. Location-specific inundation depth and duration are projected using hydrological, hydraulic and urban storm models with geographic overlays.
  • Bangladesh. Another part of the research, on flood-prone Bangladesh combines information on climate change scenarios, hydrological and hydrodynamic models to identify vulnerable areas and populations; and to quantify costs to climate-proof roads and railways, river embankments protecting productive agricultural lands, drainage systems and erosion control measures for major towns out to 2050.

Cyclone

 

The observed increase in sea surface temperatures has led to concerns about more intense cyclones. Historical records indicate that the greatest damage during cyclones results from storm surges.

The scientific evidence to date suggests that increased sea surface temperature will intensify cyclone activity and heighten storm surges. Surges will be further elevated by a rising sea level due to thermal expansion and melting of ice caps.

Knowing which countries will be most affected by cyclonic storm surges will allow better targeting of scarce resources for adaptation planning and avoid big losses later.

  • Multi-country. This research investigates the vulnerability of different coastlines to intensified storm surges using Geographic Information System (GIS) information on land areas, population density, cropland, wetlands, extent of urban areas and major cities.
  • Bangladesh. For Bangladesh, a tropical cyclone hotspot, information on climate change, hydrodynamic models and geographic overlays is integrated to assess the vulnerability of coastal areas to larger storm surges and sea-level rise by 2050. Potential damage of a 10-year return period cyclone has been computed; based on this damage scenario, the current adaptation deficit has been quantified and cost estimates for a variety of actions that could help Bangladesh develop location-specific plans to reduce future cyclone damages have been made.



 

 

Presentations
  • Presentation: A Mega-City in a Changing Climate: The Case of Water-logging in Kolkata (2011)
  • Presentation: Climate Proofing Infrastructure in Bangladesh: The Case of Inland Monsoon Flood (2010)
  • Presentation: Bangladesh Cyclone-Damage and Adaptation Cost (2010)
  • Presentation: Sea Level Rise and Storm surges: High Stakes for a Small Number of Developing Countries (2009)

 

Researchers
  • Susmita Dasgupta (World Bank)
  • Mainul Huq (Consultant)
  • Benoit Laplante (Consultant)
  • Siobhan Murray (World Bank)
  • Kiran Pandey (World Bank) 
  • Subhendu Roy (Consultant)
  • Maria Sarraf (World Bank)
  • David R. Wheeler (Center for Global Development)

 

Research outputs
 

A Megacity in a Changing Climate: The Case of Kolkata”, Susmita Dasgupta, Asvani K. Gosain, Sandhya Rao, Subhendu Roy and Maria Sarraf. Climatic Change, 2013. Vol 116, No. 3, 747-766.

Projections by the Intergovernmental Panel on Climate Change suggest an increase in the frequencies and intensities of climate extremes in the 21st century. In Asia, Kolkata, a mega-city of India has been singled out as one of the urban centers vulnerable to climate risks. Modest flooding during monsoon at high tide in the Hooghly River is a recurring hazard in Kolkata. More intense rainfall, riverine flooding, sea-level rise, and coastal storm surges in a changing climate can lead to widespread and severe flooding and bring the city to a standstill for several days.  Using rainfall data, A1FI and B1 emissions scenario, and a sea-level rise of 27 centimeters by 2050, this paper assesses the vulnerability of Kolkata to increasingly intense precipitation events of a 30/ 50/ 100 year return period. Location-specific inundation depth and duration have been projected using hydrological, hydraulic and urban storm models with geographic overlays. High resolution spatial analysis provides a roadmap for designing adaptation schemes to minimize impacts of such climate change. Modeling results show that de-silting of main sewers will reduce vulnerable population estimates by at least 5%.


Urban Flooding in a Changing Climate: Case Study of Kolkata, India,” Susmita Dasgupta, Subhendu Roy and Maria Sarraf. Asian-African Journal of Economics and Econometrics, 2012, Vol 12. No.1, 135-158.

Modest flooding during monsoon at high tide in the Hooghly river is a recurring hazard in Kolkata. More intense rainfall, riverine flooding, sea-level rise, and coastal storm surges in a changing climate can lead to widespread and severe flooding and bring the city to a standstill for several days. Using rainfall data, two different scenarios for future greenhouse gas emissions, and an assumed sea-level rise of 27 centimeters by 2050, this paper quantifies potential damage of Kolkata to increasingly intense precipitation events of a 30/ 50/ 100-year return period. By 2050, the annual expected damage in Kolkata is likely to be US$ 5 billion. Approximately 6.4 million man days will be required to recover from the additional damage.

High resolution spatial analysis provides a roadmap for designing adaptation schemes to minimize impacts of such climate change. De-silting of trunk-sewers, construction of a storm water retention infrastructure interlinking ponds and parks in the drainage infrastructure would contribute to proper watershed management and minimize impacts from flooding. Beyond these capital-intensive investments, improved policies, planning and institutions are needed to protect vulnerable population in Kolkata

 

"The Cost of Adapting to Extreme Weather Events in a Changing Climate,” Maria Sarraf, Susmita Dasgupta and Norma Adams. The World Bank Bangladesh Development Series Paper No. 28. 2011.

Foreword - by Ellen Goldstein, World Bank Country Director, Bangladesh
Global warming is expected to have severe consequences for developing countries prone to extreme weather events. Projections by the intergovernmental Panel on Climate Change and the World Meterological Organization suggest an increase in the frequencies and/or intensities of climate extremes in the 21st century. Some recent examples illustrate how severe the consequences of such extreme weather events can be: heavy floods in Australia and Brazil in 2011; extreme winter weather throughout Europe in 2010; Russia's heat wave in 2010; devastating floods in Pakistan, India, China and Mozambique in 2010; and super cyclones in Myanmar in 2008 and Bangladesh in 2007. Adaptation to increased risks of severe weather events, as well as other impacts of climate change, is essential for development . Adaptation will require climate-smart policies and investments to make countries more resilient to the effects of climate change, including losses of property, habitat, infrastructure, and lives. Country governments and hir citizens, as well as development partner institutions and climate negotiators, need a beter understanding of the potential damage due to climate change and adaptation costs to formulate effective adaptationi to extreme weather events. To shed light on potential damage from extreme weather events and adaptation costs.  World Bank staff and experts from the Institute of Water Modeling and the Center for Environmental and Georgraphic Information Services in Bangladesh have conducted a study on the potential intensification of inland monsoon floods and cyclones for Bangladesh in a changing climate.  This study is timely and of prime importance as it identifies vulnerable populations and infrastructure, quantifies outstanding deficits in dealing with current climate-related risks, and estimates the cost of adaptation to avoid further damage due to climate change.

 

 


Climate Proofing Infrastructure in Bangladesh: The Incremental Cost of Limiting Future Inland Monsoon Flood Damage,” Susmita Dasgupta, Mainul Huq, Zahirul Huq Khan, Md. Sohel Masud, Manjur Murshed Zahid Ahmed, Nandan Mukherjee and Kiran Pandey. Journal of Environment and Development. 2011. Vol. 20, No. 2, 167-190.

Bangladesh is one of the most flood-prone countries in the world. Two-thirds of the country is less than 5 meters above sea level. Past monsoon flood records indicate that about 21 percent of the country is subject to annual flooding and an additional 42 percent is at risk of floods with varied intensity. Although annual regular flooding has traditionally been beneficial, providing nutrient laden sediments and recharging groundwater aquifers, the country often experiences severe flooding during a monsoon that causes significant damage to crops and properties with adverse impacts on rural livelihoods and production. The 1998 flood inundated two-thirds of the land area, resulting in damages and losses of over $2 billion, or 4.8 percent of GDP. Climate models suggest increased precipitation, higher transboundary water flows, and sea level rise will all increase the destructive power of monsoon floods. Using climate change scenarios out to 2050, hydrological and hydrodynamic models, this paper estimates an incremental cost to climate-proof roads and railways, river embankments protecting productive agricultural lands, and drainage systems and erosion control measures for major towns of US$ 2,671 million initially, and US$ 54 million in annual recurrent costs.

This paper is based on World Bank Policy Research Working Paper 5469. November 2010.
 

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Cyclones in a Changing Climate: The Case of Bangladesh,”, Susmita Dasgupta, Mainul Huq, Zahirul Huq Khan, Manjur Murshed Zahid Ahmed, Nandan Mukherjee, Malik Fida Khan, Kiran Pandey.  2011. A revised version of this paper is forthcoming in the Climate and Development Journal.

This paper integrates information on climate change, hydrodynamic models, and geographic overlays to assess the vulnerability of coastal areas in Bangladesh to larger storm surges and sea-level rise by 2050. The approach identifies polders, coastal populations, settlements, infrastructure, and economic activity at risk of inundation, and estimates the damage versus the cost of several adaptation measures. A 27-centimeter sea-level rise and 10 percent intensification of wind speed from global warming suggests a 69 percent increase in the vulnerable zone with more than 3-meter inundation depth, and a 14 percent increase in areas with 1-3 meter inundation depth. Estimates indicate investments including strengthening polders, foreshore afforestation, additional multi-purpose cyclone shelters, cyclone-resistant private housing, and further strengthening of the early warning and evacuation system would cost more than $2.4 billion with an annual recurrent cost of more than $50 million. These estimates can serve as a prototype of the adaptation costs to extreme weather events in climate negotiations.

This paper is based on "Vulnerability of Bangladesh to cyclones in a changing climate: potential damages and adaptation cost," Susmita Dasgupta, Mainul Huq, Zahirul Huq Khan, Manjur Murshed Zahid Ahmed, Nandan Mukherjee, Malik Fida Khan, Kiran Pandey, World Bank Policy Research Working Paper 5280, 2010.

 


Sea-Level Rise and Storm Surges: High Stakes for a Small Number of Developing Countries,” , Henrike Brecht, Susmita Dasgupta, Benoit Laplante, Siobhan Murray, and David Wheeler. February 2011. Forthcoming in Journal of Environment and Development.

As the climate changes, larger cyclonic storm surges and growing populations may collide in disasters of unprecedented size. As conditions worsen, variations in coastal morphology will magnify the effects in some areas, while largely insulating others. In this paper, we explore the implications for 31 developing countries and 393 of their cyclone-vulnerable coastal cities with populations greater than 100,000. Combining the most recent scientific and demographic information, we estimate the future impact of climate change on storm surges that will strike coastal populations, economies and ecosystems. We focus on the distribution of heightened impacts, because we believe that greater knowledge of their probable variation will be useful for local and national planners, as well as international donors. Our results suggest gross inequality in the heightened impact of future disasters, with the most severe effects limited to a small number of countries and a small cluster of large cities.

This paper is based on "Climate Change and the Future Impacts of Storm-Surge Disasters in Developing Countries," Susmita Dasgupta, Benoit Laplante, Siobhan Murray, and David Wheeler, Center for Global Development Working Paper 182, September 2009.

 


Exposure of Developing Countries to Sea-Level Rise and Storm Surges,” Susmita Dasgupta, Benoit Laplante, Siobhan Murray, and David Wheeler. Climatic Change. 2011. 106: 567-579.

An increase in sea surface temperature is strongly evident at all latitudes and in all oceans. The scientific evidence to date suggests that increased sea surface temperature will intensify cyclone activity and heighten storm surges. The paper assesses the exposure of (coastal) developing countries to sea-level rise and the intensification of storm surges. Geographic Information System (GIS) software is used to overlay the best available, spatially disaggregated global data on critical exposed elements (land, population, GDP, agricultural extent and wetlands) with the inundation zones projected with heightened storm surges and a 1m sea-level rise. Country-level results indicate a significant increase in exposure of developing countries to these climate-induced changes.

 

 




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