FEATURE: Combatting surging seas in Bangladesh
Bangladesh is one of the most vulnerable countries in the world to rising tides, with its flat, low-lying topography and over 48% of its population living less than 10 metres above sea level. This feature looks at the challenges facing Bangladesh and the tools that could help it plan effectively for water-related disasters.
Climate resilience has evolved as a key component of policy discourse in countries that are frequently subjected to the threat of extreme weather events. These incidents have resulted in high civilian casualties and significant economic losses in the form of infrastructure damage and lost livelihoods. In some parts of the world, the hazard from these events is set to increase, as climate change increases the severity and frequency of extreme weather events, and climbing global temperatures bring rising sea levels.
While rising tides are a threat to all coastal countries, Bangladesh is one of the most vulnerable in the world, with its flat, low-lying topography, numerous water bodies and rivers, and over 48% of its large, dense population currently living less than 10 metres above sea level. In order for disaster risk reduction plans to be effective in the long term, it’s therefore crucial they take into account not just the current risks posed by natural hazards, but how those risks will evolve with a changing climate.
The Raising Risk Awareness project has sought to promote an understanding of this changing risk, to aid evidence-based decision-making regarding recovery, reconstruction, and risk reduction. Hina Lotia, CDKN’s Asia lead for the Raising Risk Awareness project, sees it as a valuable opportunity for knowledge sharing and collaboration across countries, allowing “scientists and communication experts from the US and the UK to collaborate with their counterparts in South Asia and East Africa, to devise holistic strategies to cope with complex climate challenges.”
Understanding rising sea levels
Climate Central – a leading US-based science communication organisation – has developed the Surging Seas tool to help vulnerable countries and regions better understand their exposure to flooding and rising sea level. The web-based tool comprises three main components:
- Risk Zone Map, which shows local sea level rise and flood risk projections and maps areas falling below the different water levels that could result;
- Risk Finder, which quantifies land and population exposed at these levels, from district through national levels; and
- Mapping Choices, which visualizes the long-term local consequences locked in by different carbon pollution scenarios.
The Surging Seas toolkit could provide crucial information to help Bangladesh plan effectively for water-related disasters. Dr. Benjamin Strauss, the architect of the Surging Seas tool, expressed his optimism in incorporating the toolkit in the Bangladesh context, “The Surging Seas tool can be used in Bangladesh to explore projected high tide lines and chronic flood elevations as sea levels rise, to identify land areas lower than these levels, and to estimate how many people live in these areas.”
This project has undertaken initiatives to develop and raise awareness of the Surging Seas tool in Bangladesh in a number of ways. Elements of the tool, and supporting material, have been translated into Bengali. In addition, a meeting was held in Dhaka that brought together a wide range of local stakeholders as well as the team behind the Surging Seas tool. The meeting was an opportunity to share learning and knowledge, strengthen local capacity to use the toolkit, and identify priority areas of interest for future development of the tool.
Through the project, links have been forged the Climate Central team, and local Bangladeshi experts in sea level rise, floods and disaster management, such as the Institute of Water Modelling (IWM). Climate Central are now looking at future partnership opportunities to continue to tailor the tool to the Bangladesh context. By collaborating with in country counterparts, they aim to incorporate expertise from Bangladeshi scientists and practitioners, and ensure the tool is complementary to local disaster risk reduction efforts.
Preparing for future hazards
According to analysis presented at the workshop, if global carbon emissions were to continue under the IPCC’s high emissions scenario (RCP 8.5), over 1,000 km2 of land in Bangladesh could be permanently under the new high tide line by 2100, on which more than 800,000 people currently live. Twice as much land and more than 2 million people are at risk of frequent flooding from storm surges plus tides. RCP 8.5 assumes increasing greenhouse gas emissions over time that may lead to a temperature increase between 3°C and 5°C above preindustrial levels by 2100. In Paris, countries agreed to mitigate emissions to avoid this extreme scenario; however, regardless of how successful they are in meeting their pledges, some degree of sea level rise is still anticipated.
According to CDKN’s country advisor for Bangladesh, Dr. Munjurul Hannan Khan, the Surging Seas tool would add value to the existing work being done in Bangladesh regarding disaster risk reduction. “The Bangladesh Government has taken a number of initiatives for fighting adverse impacts of the changing climate”, underscores Dr. Khan, “making synergies with the existing knowledge and projections from the toolkits can be very useful for formulating better policies regarding climate change and disaster management issues.”
By providing information relating to future climate risks and the vulnerability and exposure contexts of different areas, the Surging Seas tool is anticipated to better inform policy planning; disaster risk reduction; and enable more effective media reporting of organisations related to science, communication and policy.
The Raising Risk Awareness initiative brings together the Climate and Development Knowledge Network (CDKN) with scientists from the World Weather Attribution (WWA) initiative. WWA is an effort led by Climate Central with the Red Cross Red Crescent Climate Centre, University of Oxford, University of Melbourne and Royal Netherlands Meteorological Institute.