Coastlines: the frontline of climate change

Although GHG wrap the planet like a massive gaseous blanket that traps heat within the surface, contributions to global warming have varied substantially among nations², with highest per capita emissions in high and middle-income countries^3,4. Low-income countries, on the other hand, contribute substantially less to global GHG emissions compared to the top emitters, but suffer the worst effects of climate change⁵. Almost all of the world's 60 million poor people live in rural low-elevation coastal zones (LECZs)⁶ and are increasingly at risk of hazards associated with climate change such as coastal floods and landslides⁷.

Per capita and absolute CO₂ consumption emissions by four global income groups for 2015. Source: UNEP (2020)⁴

The livelihoods and cultural values of poor coastal communities depend directly on coastal and marine ecosystem services (ES), such as nursery habitats for fish, fishery catches and biodiversity and aesthetic appreciation for tourism⁶. As the sea temperature and sea level rise, and the weather becomes more unpredictable, with extreme weather events becoming more frequent⁸, provision of these ES and associated socioeconomic benefits hang in the balance. Combined with other major environmental problems, namely pollution, coastal eutrophication and direct conversion and loss of biodiversity⁵, climate-related impacts in these areas are magnified, causing economic losses, deaths and injuries from the increased hazards associated with climate change⁸.

Brazil is among the 15 nations that are most-at-risk of climate change related impacts⁶. 60% of the country’s population live in highly urbanized areas located in LECZs that are naturally prone to coastal floods caused by the simultaneous occurrence of heavy rains and spring tides^9,10. Approximately 40% of Brazil’s rural population live in LECZs, are poor and rely on natural barriers such as mangroves for protection against storms and other coastal hazards that are set to intensify in the near future^6,11. Because of the rising sea level, alterations to river dynamics, deforestation and land conversion, these natural barriers are eroding away and poverty-stricken coastal areas are becoming even more vulnerable to climate-related impacts^12,13. A report produced by the Brazilian Panel on Climate Change on climate change impacts, vulnerabilities and adaptation, concluded that several coastal areas in Brazil present high or very high vulnerability to climate change¹⁴. However, the lack of detailed assessments of Brazil’s coastal vulnerability to the impacts of climate change, particularly with regards to sea level rise, prevents the identification of areas that are more at risk and the development of context-specific adaptation, contingency and mitigation strategies¹⁵.

Mangrove forests in northeast Brazil provide multiple ecosystem services that benefit coastal populations: habitat for biodiversity, fisheries, coastal protection, estuarine filtration, carbon sequestration and storage, local climate regulation and cultural values¹³. Photo Credit: Clemente Coelho Jr./ Instituto Bioma Brasil

Coastlines are at the frontline of climate change and for this reason adaptation strategies should be at the forefront of climate mitigation action plans. Adapting to climate change requires considerable structural investment and can be seen as a heavy burden on the public purse, but not adapting is significantly more costly with potential catastrophic consequences¹⁵. A study conducted in Brazil for the city of Santos revealed that the implementation of adaptive construction projects in the Ponta da Praia area of Santos and the northwest of the city would cost at least R$300 million (£41 million). On the other hand, failure to adapt to climate change would cost at least R$1.5 billion (£205 million), in addition to the suffering it would cause the population¹⁷.

Adapting to climate change does not necessarily need to be very expensive. Nature-based strategies can be used to restore and improve the health of habitats and ecosystems that deliver climate-related ES, enhancing the environment at the same time as helping communities to adapt to some of the adverse effects of climate change¹⁸. Adaptation strategies that harness biodiversity and ES to increase resilience and reduce the vulnerability of human communities and natural systems to climate change are called Ecosystem-based Adaptation (EbA) strategies¹⁹. EbA is often cost-effective and can be more so than alternative approaches to adaptation such as investment in infrastructure²⁰. In coastal areas, EbA strategies include restoration and protection of natural barriers against sea level rise (e.g., mangroves, coral reefs and dunes), sustainable practices in agriculture and aquaculture, integrated water resource management, identification of risk areas and establishment of contingency plans, information and alert systems, data collection and monitoring programmes, among other actions¹⁵. Additionally, EbA can provide a variety of important wide-reaching and potentially long-lasting adaptation-related benefits (e.g., disaster risk reduction, climate change mitigation), ecosystem-related benefits (e.g., carbon sequestration and storage, biodiversity conservation, water quality improvement), and multiple social co-benefits (e.g., livelihood improvements, strengthened capacity, knowledge or awareness, strengthened community relations, governance improvements)²¹.

In northeastern Brazil, a collaborative research project between Brazil and UK researchers is helping deprived coastal communities in the state of Alagoas adapt to some of the effects of climate change using EbA. The project entitled “Será que chove?” (Will it rain?) is funded by the British Council and the Ayni Institute as a result of the “Empowering Traditional Communities in the Brazilian Coastal Zone to Adapt to the Climate Crisis” workshop ran early on this year. Será que chove? is developing an innovative low-cost seasonal forecasting and alert system for the rainy season, fed by sea surface temperature (SST) data and local empirical knowledge on perceived rainy season patterns to calibrate a weather prediction model. The project also runs EbA capacity building training sessions for local community leaders and stakeholder representatives aiming to foster climate-change awareness and support communities to create their own EbA projects to address some local climate-related issues.

Alongside fisheries, ecotourism is an important source of income for poor communities along the coast of Alagoas State, in northeast Brazil. These activities depend directly on ecosystem services that are likely to be affected negatively by climate-related disturbances. Photo credit: Iran Normande.

People around the world have been adapting to climate variability for centuries. Besides being way cheaper than remediating, adapting to the challenges of climate change also offers long-term solutions to help protect populations and the environment from damage and loss^20,21. There is no doubt that curbing GHG emissions is fundamental to slowdown climate change and alleviate its impacts. However, the need for humankind to adapt to the world of its own making must be given equal weight in the climate war. This is a war fought by all, but the heaviest brunt of the fight is being felt more intensely by the disadvantaged, who in their majority lack the means and the tools to protect themselves, their homes and their resources against an environmental hazard they did not begin or scarcely contributed to in the first place.

About the author

Aline da Silva Cerqueira is an Anglo-Brazilian Marine Biologist and a NERC funded PhD researcher in the Department of Geography at King’s College London jointly with the ZSL Institute of Zoology. She is an Ecosystem-based Adaptation (EbA) researcher and instructor in the joint Brazil-UK climate change mitigation research project “Será que chove?” in Northeast Brazil. She is also the co-founder of AQUASIS, a conservation NGO dedicated to the protection of endangered species and important habitats in northeastern Brazil, and a research partner with AQUASIS’ Marine Mammals Program, focused on the conservation of the manatee (Trichechus manatus), and the Guiana dolphin (Sotalia guianensis), two endangered species that have the highest mortality rate in the region. Aline is a member of Liga das Mulheres pelo Oceano (Women's League for the Ocean), a network of women from a range of backgrounds working collectively to boost the impact of actions and ideas for ocean conservation. She is also a collaborator in the Ocean Decade Scientists Network.

Video contributions

Anna Maria Cárcamo is an Environmental Lawyer and Master of Environmental Management from the Yale School of Forestry and Environmental studies. She also has a Law degree from PUC-Rio with a minor in International Relations. Over the years, Anna Maria has had several roles as a legal policy advisor. One of her latest roles was at the International Rivers in Brazil, where she mainly focused on strengthening river protections in Brazil, considering social and environmental aspects, and working with partners to prevent threats to rivers and those that protect them and create responsibility for social, environmental impacts. Anna is now a United Nations Climate Fellow.

Dr Isabela Battistello Espíndola is a PhD candidate in Human Geography at the University of São Paulo (USP). She has an M.Sc. in Environmental Sciences at the Federal University of São Carlos (UFSCar) and a B.A. in International Relations and Economics from the Faculty of Campinas (FACAMP). Since her master's degree, she has worked with ​​international relations and environmental issues, focusing on transboundary water resources. Through her work and research, Isabela has participated in numerous national and international events such as the Youth Assembly (2018), the Tsukuba Global Science Week (2018), the World Youth Forum (2019), the International Student Festival of Harkat (2020), the Youth20 Summit (2020), the General Assembly of the World Youth Parliament for Water (2021), among others. In addition to being a researcher at the Laboratory of Political Geography from USP, she is a FAPESP fellow and a member of the Brazilian Steering Committee of the BRICS CCI Young Leaders. She also participates in the Water Youth Network, Young Leaders of the Americas Initiative, Organization for Women in Science for the Developing World (OWSD), United People Global, Climate Reality Project, International Studies Association, Latin American Studies Association and World Youth Parliament for Water. She has a special interest in international relations, hydropolitics and transboundary cooperation, as well as human rights, sustainable development and environmental policy.

Luiz Amore is the International Coordinator of the Project “Preparing the Ground for the Implementation of La Plata Basin Strategic Action Program in the Intergovernmental Coordination Committee of the La Plata Watershed - CIC” (GEF, Development Bank of Latin America - CAF and the Organization of the American States - OAS), since July 2019. He was the Head of International Cooperation at the Brazilian National Water Agency (ANA) for over ten years, during which he was responsible for almost 30 South-South bilateral cooperation projects both in Latin America and Africa. Furthermore, he was the General Secretariat of the Guarani Aquifer Project (Global Environment Facility - GEF, World Bank and Organization of American States - OAS) in Montevideo under the direction of the Project Steering Committee (Argentina, Brazil, Paraguay and Uruguay).

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