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Climate change impacts and adaptation in coastal areas

 

sea level rise poster

This World Bank research on coastal areas focuses on sea level rise on potential impacts on developing countries with coastal areas, and increasingly intense storm surge and potential for impacts on coastal populations and economic productivity

Contact: Susmita Dasgupta, sdasgupta@worldbank.org

 

Sea level rise  | Storm surge | Data | Researchers | Presentations | Research outputs 


Climate change is a serious threat to coastal areas with concentrated populations of people, ecosystems, and economic activity. Potential impacts from sea level rise and increased storm surge include:

  • loss of land area due to sea level rise and increased erosion;
  • inundation, flood and storm damage, and saltwater intrusion;
  • and ecosystems consequences of lost wetlands, coral bleaching (from higher sea water temperatures), ocean productivity shifts, and species migration.

The actual socio-economic impacts of losses of coastal property, habitat, infrastructure, and lives will depend on countries’ ability to adapt to the potential impacts of climate change.

Sea level rise 
 

 

Scientific evidence now suggests that sea level could rise by more than a meter within this century, and the unexpectedly rapid breakup of the Greenland and West Antarctic ice sheets might produce a 3-5 meter rise in sea level.

The magnitude of such changes could be catastrophic for many developing countries. Estimates suggest that even a one-meter rise in sea level in coastal countries of the developing world would submerge 194,000 square kilometers of land area, and displace at least 56 million people. This research assesses the consequences of SLR for at-risk developing countries on land, population, agriculture, urban extent, wetlands and GDP.At the country level results are extremely skewed.

Tens of millions of people in the developing world may be potentially displaced or their income from agricultural or economic activites in these zone severely impacted.

So far, severe impacts from sea level rise seem limited to a relatively small number of countries (e.g., Vietnam, Bangladesh, Egypt, the Bahamas), however, the consequences of SLR are potentially catastrophic. For many others, including some of the largest (e.g., China), the absolute magnitudes of potential impacts are very large.

Storm surge

 

 

The observed increase in sea surface temperature has lead to concerns about ocean warming, and the connection to more intense cyclone activity and heightened storm surges. Knowing which countries will be most affected will allow better targeting of scarce resources for adaptation planning and avoid big losses later.  This research investigates the vulnerability of different coastlines to intensified storm surges using using Geographic Information System (GIS) information on land areas, population density, cropland, wetlands, extent of urban areas and major cities. 

For tropical cyclone hotspot Bangladesh, information on climate change, hydrodynamic models and geographic overlays were 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 and itemized cost estimates that could help Bangladesh develop location-specific plans to reduce future cyclone damages has been listed.

 
Data
Presentations
Researchers
  • Susmita Dasgupta (World Bank)
  • Benoit Laplante (Consultant)
  • Craig Meisner (World Bank)
  • Siobhan Murray (Consultant)
  • David R. Wheeler (Center for Global Development)
  • Jianping Yan (Consultant)

Research outputs

"Drinking water salinity and infant mortality in coastal Bangladesh." Susmita Dasgupta, Mainul Huq, David Wheeler, World Bank Policy Research Working Paper 7200, 2015

Bangladesh, with two-thirds of its land area less than five meters above sea level, is one of the most climate-vulnerable countries in the world. Low-lying coastal districts along the Bay of Bengal are particularly vulnerable to sea level rise, tidal flooding, storm surges, and climate-induced increases in soil and water salinity. This paper investigates the impact of drinking water salinity on infant mortality in coastal Bangladesh. It focuses on the salinity of drinking water consumed during pregnancy, which extensive medical research has linked to maternal hypertension, preeclampsia, and post-partum morbidity and mortality. The study combines spatially-formatted salinity measures for 2001-09 provided by Bangladesh with individual and household survey information from the Bangladesh Demographic and Health Surveys for 2004 and 2007. It uses probit and logit analyses to estimate mortality probability for infants less than two months old. Controlling for many other determinants of infant mortality, the analysis finds high significance for salinity exposure during the last month of pregnancy and no significance for exposure during the preceding months. The estimated impact of salinity on infant mortality is comparable in magnitude to the estimated effects of traditionally-cited variables such as maternal age and education, gender of the household head, household wealth, toilet facilities, drinking water sources, and cooking fuels.

"Facing the hungry tide : climate change, livelihood threats, and household responses in coastal Bangladesh, Volume 1."  Susmita Dasgupta, Md. Moqbul Hossain, Mainul Huq, David Wheeler, World Bank Policy Research Working Paper 7148, 2014

This paper quantifies the impact of inundation risk and salinization on the family structure and economic welfare of coastal households in Bangladesh. These households are already on the "front line" of climate change, so their adaptation presages the future for hundreds of millions of families worldwide who will face similar threats by 2100. The analysis is based on a household decision model that relates spatial deployment of working-age, migration-capable members to inundation and salinization threats. The analysis uses appropriate estimation techniques, including adjustments for spatial autocorrelation, and finds that households subject to high inundation and salinization threats have significantly higher out-migration rates for working-age adults (particularly males), dependency ratios, and poverty incidence than their counterparts in non-threatened areas. The findings indicate that the critical zone for inundation risk lies within four kilometers of the coast, with attenuated impacts for coastal-zone households at higher elevations. The results paint a sobering picture of life at the coastal margin for Bangladeshi households threatened by inundation and salinization, particularly households that are relatively isolated from market centers. They respond by "hollowing out," as economic necessity drives more working-age adults to seek outside earnings. Those left behind face a far greater likelihood of extreme poverty than their counterparts in less-threatened areas. The powerful results for market access, coupled with previous findings on salinity and road maintenance, suggest that infrastructure investment may offer a promising option. Road improvements that reduce travel times for isolated settlements compensate them for an increase in salinity. Thus, road improvement may warrant particular attention as an attractive adaptation investment in coastal Bangladesh.

 

"Climate change, groundwater salinization and road maintenance costs in coastal Bangladesh, Volume 1." Susmita Dasgupta, Md. Moqbul Hossain, Mainul Huq, David Wheeler, World Bank Policy Research Working Paper 7147, 2014

The potentially-adverse impact of salinity on paved roads is well-established in the engineering literature. The problem seems destined to grow, as climate-related changes in sea level and riverine flows drive future increases in groundwater salinity. However, data scarcity has prevented systematic analysis for poor countries. This paper assesses the impact of groundwater salinity on road maintenance expenditures in the coastal region of Bangladesh. The assessment draws on new panel measures of salinity from 41 stations in coastal Bangladesh, and road maintenance expenditures, income, road network length, and road surfaces from 20 coastal municipalities. In a model relating maintenance expenditure for paved roads to groundwater salinity, municipal income, and road network length, large and significant effects are found for salinity. The regression model is used to predict the effect of within-sample salinity variation on road maintenance expenditure share, holding municipal income and road length constant at sample mean values. Increasing salinity from its sample minimum to its sample maximum increases the predicted road maintenance expenditure share by 252 percent. The implied welfare impact may also be substantial, particularly for poor households, if diversion of expenditures to road maintenance reduces support for community sanitation, health, and other infrastructure related programs.

"Climate change, soil salinity, and the economics of high-yield rice production in coastal Bangladesh," Susmita Dasgupta, Md. Moqbul Hossain, Mainul Huq, David Wheeler, World Bank Policy Research Working Paper 7140, 2014.

It is a virtual certainty that sea-level rise will continue throughout the century and beyond 2100 even if greenhouse gas emissions are stabilized in the near future. Understanding the economic impacts of salinity intrusion thus is essential for planning adaptation in low-lying coastal areas around the world. This paper presents a case study in Bangladesh on how climate change leads to the spread of soil salinity and the impact on agricultural production in the coastal region. The analysis is conducted in two stages. The first stage predicts future soil salinity for 69 subdistricts, taking into account climate-induced changes in river salinity, temperature, and rainfall by 2050. The second stage uses econometric analysis to predict the impact of climate-induced increases in soil salinity on the output and price of high-yielding-variety rice. The findings indicate output declines of 15.6 percent in nine subdistricts where soil salinity will exceed 4 deciSiemens per meter before 2050. Without newly developed coping strategies, the predicted changes will produce significant income declines from high-yielding-variety rice production in many areas, including a 10.5 percent loss in Barisal region and a 7.5 percent loss in Chittagong region.

River Salinity and Climate Change: Evidence from Coastal Bangladesh,” Susmita Dasgupta, Farhana Akhter Kamal, Zahirul Huque Khan, Sharifuzzaman Choudhury and Ainun Nishat,  World Bank Policy Research Working Paper 6817, 2014.

In a changing climate, saltwater intrusion is expected to worsen in low-lying coastal areas around the world. Understanding the physical and economic effects of salinity ingress, and planning adaptation, are key to the long-term development of countries for which sea level rise has been identified as a major risk from climate change. This paper presents a study conducted in Bangladesh, which quantifies the prospective relationship between climate-induced changes in sea level, temperature, rainfall, and altered riverine flows from the Himalayas, and the spread and intensity of salinization on river water in the coastal zone for 2050. The research takes into account the projected land subsidence of the Ganges Delta, as well as alternative scenarios of upstream withdrawal of freshwater. The findings indicate that climate change will cause significant changes in river salinity in the southwest coastal area of Bangladesh by 2050. These changes are likely to lead to significant shortages of drinking water in the coastal urban areas, scarcity of water for irrigation for dry-season agriculture, and significant changes in the coastal aquatic ecosystems. Changes in the availability of freshwater fish will likely affect the composition of capture fishery, although the increase in brackish water will enhance opportunities for brackish water aquaculture. Assessment of location-specific economic impacts of the changes in river salinity, identification of suitable adaptation alternatives, and costing of adaptation are high priorities for further analysis.

"Sea-level rise and coastal wetlands: impacts and costs," Brian Blankespoor, Susmita Dasgupta and Benoit Laplante, World Bank Policy Research Working Paper 6277, 2012.

Scientific evidence indicates that global warming could well lead to a sea-level rise of 1 meter or more in the 21st century. This paper seeks to quantify how a 1-meter sea-level rise that would affect coastal wetlands in 76 developing countries and territories, taking into account how much of wetlands would be submerged and how likely the wetlands would move inland as the coastline recedes. It is estimated that approximately 64 percent of the freshwater marsh, 66 percent of Global Lakes and Wetlands Database coastal wetlands, and 61 percent of brackish/saline wetlands are at risk. A large percentage of this loss would be shouldered by two regions: East Asia and the Pacific, and the Middle East and North Africa. At the country level, the results are extremely skewed with a small number of countries being severely affected. In East Asia, China and Vietnam would bear the brunt of these losses. In the Middle East and North Africa, Libya and Egypt would see the most losses. A rough estimate of the economic value of the goods and services produced by wetlands at risk is approximately $630 million per year in 2000 U.S. dollars.

 

"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.

This paper explores the implications of sea-level rise and storm surges for 84 developing countries and 577 of their cyclone-vulnerable coastal cities with populations greater than 100,000. Combining the most recent scientific and demographic information, they 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.

An additional spreadsheet (.xls 53k), of special interest to planners in developing countries, includes more complete city-level results.

 


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.

 

 


"The Impact of Sea-Level Rise on Developing Countries: A Comparative Analysis," Susmita Dasgupta, Benoit Laplante, Craig Meisner, David Wheeler, Jianping Yan, World Bank Policy Research Working Paper 4136, 2009.

Sea level rise (SLR) due to climate change is a serious global threat. The scientific evidence is now overwhelming. Continued growth of greenhouse gas emissions and associated global warming could well promote SLR of 1m-3m in this century, and unexpectedly rapid breakup of the Greenland and West Antarctic ice sheets might produce a 5m SLR. In this paper, the authors have assessed the consequences of continued SLR for 84 developing countries. Geographic Information System (GIS) software has been used to overlay the best available, spatially-disaggregated global data on critical impact elements (land, population, agriculture, urban extent, wetlands, and GDP) with the inundation zones projected for 1-5m SLR. The results reveal that hundreds of millions of people in the developing world are likely to be displaced by SLR within this century, and accompanying economic and ecological damage will be severe for many. At the country level, results are extremely skewed, with severe impacts limited to a relatively small number of countries. For these countries (such as Vietnam, A. R. of Egypt, and The Bahamas), however, the consequences of SLR are potentially catastrophic. For many others, including some of the largest (such as China), the absolute magnitudes of potential impacts are very large. At the other extreme, many developing countries experience limited impacts. Among regions, East Asia and the Middle East and North Africa exhibit the greatest relative impacts. To date, there is little evidence that the international community has seriously considered the implications of SLR for population location and infrastructure planning in developing countries. The authors hope that the information provided in this paper will encourage immediate planning for adaptation.

 


"The Impact of Sea-Level Rise on Developing Countries: A Comparative Analysis," Susmita Dasgupta, Benoit Laplante, Craig Meisner, David Wheeler, Jianping Yan, Climate Change 93(3): 379-88, 2009. (see abstract above)

 


"Climate Change and Sea Level Rise: A Review of the Scientific Evidence," Susmita Dasgupta and Craig Meisner, Environment Department Paper 118, World Bank, Washington, DC, 2009. (PDF 2.03mb)

Sea-level rise (SLR) due to climate change is a serious global threat: The scientific evidence is now overwhelming. The rate of global sea level rise was faster from 1993 to 2003, about 3.1 mm per year, as compared to the average rate of 1.8 mm per year from 1961 to 2003 (IPCC, 2007); and significantly higher than the average rate of 0.1 to 0.2 mm/yr increase recorded by geological data over the last 3,000 years. Anthropogenic warming and SLR will continue for centuries due to the time scales associated with climate processes and feedbacks, even if greenhouse gas concentrations were to be stabilized. This paper reviews the scientific literature to date on climate change and sea level rise.

There appears to be a consensus across studies that global sea level is projected to rise during the 21st century at a greater rate than during the period 1961 to 2003 and unanimous agreement that SLR will not be geographically uniform. Ocean thermal expansion is projected to contribute significantly, and land ice will increasingly lose mass at an accelerated rate. But most controversial are the mass balance loss estimates of the Greenland and Antarctic Ice Sheets and what the yet un-quantified dynamic processes will imply in terms of SLR. Recent evidence on the vulnerability of Greenland and west Antarctic ice sheets to climate warming raises the alarming possibility of SLR by one meter or more by the end of the 21st century.

 


"Sea-Level Rise and Storm Surges: A Comparative Analysis of Impacts in Developing Countries," Susmita Dasgupta, Benoit Laplante, Siobhan Murray, and David Wheeler, World Bank Policy Research Working Paper 4901, 2009.

An increase in sea surface temperature is evident at all latitudes and in all oceans. The current understanding is that ocean warming plays a major role in intensified cyclone activity and heightened storm surges. The vulnerability of coastlines to intensified storm surges can be ascertained by overlaying Geographic Information System information with data on land, population density, agriculture, urban extent, major cities, wetlands, and gross domestic product for inundation zones likely to experience more intense storms and a 1 meter sea-level rise. The results show severe impacts are likely to be limited to a relatively small number of countries and a cluster of large cities at the low end of the international income distribution.

 




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