City Slums

Inhabitants of city slums are at extreme risk to climate change. Slums grow at a rapid pace because of in-migration of people from disaster prone areas, and growing poverty in rural areas and more opportunities in urban areas.

The growth rate can be almost double the average population increase. However, slums grow unplanned leaving little space for drainage, water supply and waste management, as well as green areas with trees to reduce heat waves.  These areas also are often in marginalized, exposed, and/or low lying locations, already susceptible to floods and waterlogging. Especially during annual monsoons or rainy seasons, slum areas easily overflow with water and sewage from unsafe toilets, and litter blocks drains which overflow. This has severe consequences for the health and well-being of already vulnerable inhabitants. People also do not live in proper shelters but in shacks, on plots that often are not owned by themselves, with little incentives to upgrade and maintain the area. Inhabitants are often illiterate, do not feel empowered, and do not know and lack information on how to demand help from the local government.

Slums often arise because they are closely located to jobs in the city, and therefore relocation of slums and their inhabitants is often difficult.

Lagos, Nigeria: Everyday life in the slum of megacity. Lack of drainage and waste collection.
Lagos, Nigeria: Everyday life in the slum of megacity. Lack of drainage and waste collection | Photo: peeterv (istock)

Slum upgrading

Successful slum upgrading exists, which addresses the multiple challenges in slums, including land ownership and the linked system of drainage - water supply and waste management.

For example, WSUP, and Architects without borders have managed to upgrade slums in Maputo and elsewhere. Read about it here in their new report.

Other lessons learnt will soon be published here.


Cape Town was near day zero in 2018. The drought that threatened to turn off the taps in Cape Town was made three times more likely by global warming, according to a study. Credit picture perfect istock.
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Urban Resilience

Disasters, climate change, and rapid urbanization pose a serious risk to the provision of urban water services including safe drinking water, sanitation, and safe drainage.

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The Lena Delta Reserve seen from a satellite
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Water defines and enables human development. Ecosystems and economies depend on water.  The impact of climate change will be most acutely expressed through water.  Deltas are particularly vulnerable to water-related climate risks.

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Man in the sea in Bangladesh, istock photo, Credits: Mudassir Hossain
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Coastal Areas

Human societies will need to adapt to sea level rise, which means flooding, increasing risk of storm surges, coastal erosion and the loss of low-lying coastal systems.

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A desert plain with three trees and amountain
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Drylands are defined by a scarcity of water, and cover more than 40% of the earth surface. Drylands are present in more than 100 countries and home to over 2 billion people.


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Cross Cutting

Eifel, Elz valley, flood disaster, July 15th 2021. Europe is highly urbanised and has too few natural buffers that can infiltrate extreme amounts of heavy rainfall. Markus Volk. istock.
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Nature based solutions

Nature based solutions work with and enhance nature to restore and protect ecosystems and to help society adapt to the impacts of climate change. Adaptation calls for the increased use of nature based solutions with multiple benefits which at the same time provides for livelihoods, ecosystem life support and community resilience.

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A river basin in a mountanous region.
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River Basins

Collaboration in a river basin is needed to share increasingly scarce resources, manage water related risks emerging from various land uses and prevent flooding by linking upstream and downstream activities. Upstream areas need to ensure spatial planning that is mitigating floods for downstream areas. 

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