Climate change harms Africa city, informal settlements hit worst

By Abay Yimere

Ethiopia, the second most populous country in Africa, has one of the fastest growing economies on the continent. But the country’s rapid urbanization rate is fed by refugee migration and informal settlements that are highly vulnerable to the physical risks of climate change. Addis Ababa, the capital city, is home to some of the highest numbers of informal and slum settlements in the world. This makes Ethiopia an important country for research, particularly in relation to climate-related migration patterns.

Research conducted by the Climate Policy Lab at The Fletcher School at Tufts University and Woodwell Climate Research Center, illustrates the links between climate change, land and water management, and vulnerable populations in Addis. The research examines projected changes in extreme heat, drought, and flooding and our analysis explores how these changes have affected—and will continue to impact—informal settlements, land and water use, and development plans within the city. We found that rural-urban migration patterns are resulting in high rates of informal settlements along riverbanks, slopes, and floodplains and spurs vector-borne and waterborne diseases in Addis Ababa.

Impact on informal settlement and infrastructure

According to a 2007 census conducted by the Ethiopian Central Statistics Agency, the population of Addis Ababa was estimated to be approximately 3.4 million in 2017, with a projected increase to 8.9 million by 2037. The rapid rural–urban migration rate of 3.8% is the major contributor to this population growth, resulting in a tripling of the city’s population and compounding its socioeconomic and environmental problems. Migrants from other parts of the country account for approximately 40% of the city’s population.

Low housing standards and widespread informal settlements in open areas, riverbanks, floodplains, and green spaces have eroded riparian buffer zones, contributing to an increase in landslides and floods. This, coupled with inadequate sanitation, has turned the city’s rivers into open sewers. Incidents of urban fires are also high in informal settlements, slums, and low-income, densely populated areas, exacerbating the lack of access to basic needs and public amenities. All of these factors increase the vulnerability of the city, particularly for poorer citizens and residents of informal settlements.

The widespread occupation of riverbanks by informal settlements, coupled with the lack of adequate sanitation, has led to riverbank erosion and transformed the city’s rivers into open sewers, further impacting the city’s infrastructure and informal settlements.

Impacts on vector-borne and waterborne diseases

Mosquitoes thrive and survive within a certain temperature range, with high biting rates, transmission, egg-to-adult survival, fertility, and lifespan occurring between 23°C and 34°C, reaching their peak between 26°C and 29°C.

Using Woodwell Climate’s global climate model, we forecasted Addis Ababa’s future climate as well as the probability and magnitude of extreme climate hazards. Using historical data from 2000 to 2020 as a baseline, our research found that the annual and three-month (March, April, and May) average temperatures of Addis Ababa fall within the range of the mosquitoes’ peak transmission and distribution environments, see figure 1.

Figure 1. Daily Maximum Temperature Distributions for Addis. (a) Annual. (b) March, April, and May (warmest season)

Some parts of Addis Ababa have experienced intensification and transmission of malaria, while others have become vulnerable to mosquito invasions and encroachments. Moreover, the temperature projections of our model aligned with human-observed malaria data, with incidents of malaria in the subcities, such as Nifas Silk-Lafto, Kolfe Keranio Addis Ketema, and Lideta, falling within the mosquito’s maximal transmission and territorial expansion range, see figure 2. Similar research has linked recent malaria case spikes in Addis Ababa to the arrival of the Asian invasive Anopheles stephensi trait in Ethiopia and beyond.

Figure 2. Observed Malaria Incidence Rates in Addis Ababa.

Our study focused on the impact of climate change on infection disease transmission, distribution, and length of transmission seasons, e.g., for foodborne, waterborne, and vector-borne diseases. Additionally, increasing hazards such as floods, droughts, and landslides are affecting community sanitation and present potential sources of disease outbreaks. This underscores the urgent need to build resilient infrastructure and societies to prevent key infectious diseases before they become public health concerns.

Furthermore, our research found that informal settlements and slums in Addis Ababa are not only highly exposed to climate hazards but are also a vulnerable section of society with limited adaptation capabilities and scarce resources to deal with the consequences of these hazards.

Controlling the conducive variables for vector-borne pathogens is the most effective way of preventing and reducing malaria transmission. Further, evidence suggests that malaria can be eliminated; however, this cannot be accomplished through a business-as-usual approach. Instead, it needs a systematic and targeted approach supported by political will, robust community engagement, continued funding, improved monitoring and evaluation, and long-term surveillance to identify sources and pathways of malaria transmissions, which can aid in the elimination of vectors and save lives.

Implications for policy

The impacts of climate change and in-migration are exacerbating challenges related to urban housing developments, construction, urban agriculture, health, and infrastructure in Addis Ababa. To address these challenges, policy design processes must reflect the new reality and prioritize efforts to mitigate and cope with the impacts of climate change.

An integrated and evidence-based climate policy response approach is critical to synergize adaptation and mitigation actions, improve resilience, and reduce maladaptation. Involvement of stakeholders in the policy-design process can improve the quality of the policies, increase government transparency, and foster trust and ownership for more effective interventions.

Abay Yimere is a Post Doctoral Scholar at the Climate Policy Lab at The Fletcher School.

Read the full report here.

* This research was led by Tufts Professors Karen Jacobsen and Justin B. Hollander.  Woodwell contributors included Christopher Schwalm, Dominic Dusseau, Kelly Gassert, Alexandra Naegele, and Anneka Williams.  Tufts contributors included Abay Yimere, Mieke van der Wansem, Amy Jaffe, Bethany Tietjen, Jake Sottak, Hallie Westlund, Rachael Lew, Sonya Sternlieb, Grace Wu, Ryn Piasecki, Rachel Herman and Elli Sol Strich.