Urbanisation, sanitation and environmental change

Even with the adaptation techniques put in place to make agriculture more resilient to environmental changes (as discussed previously), crop failures have led to increased urbanisation across sub-Saharan Africa, with farmers seeking alternative employment opportunities; rural-urban migration accounted for half of Africa’s urban growth between the 1960s and 1990s (Barrios et al. 2006). Africa’s urban population reached almost 350 million in 2014 (Henderson et al. 2016), and SSA’s urban population is predicted to reach 760 million by 2030 (Ramin 2009).

However, when urban immigrants arrive at their destination, life doesn’t get much easier. 71.8% of the urban population of SSA live in slums which lack basic sanitation and drinking water supplies. In 2000, 30-50% of African urban dwellers didn’t have access to a safe water supply, and even those with access often couldn’t afford to take advantage of it (Ramin 2009). The already low-quality urban water and sanitation infrastructure is predicted to worsen with the combined pressures of urbanisation and climate change (Oates et al. 2014).

How does climate change affect urban water and sanitation infrastructure?

An increase in rainfall intensity due to climate change is predicted, which means more urban flooding, particularly in countries with tropical climates that already experience intense tropical rainstorms and flash floods. The nature of urban infrastructure exacerbates the impact of these rainfall events: roads and paved surfaces obstruct natural channels, and drains are unable to cope with the huge volumes of water. And since the urban poor are more likely to settle in unfavourable flood-prone areas of the city, they are most vulnerable to flood events (Douglas et al. 2008).

In the short term, flooding can damage drinking-water infrastructure, preventing access to water supplies for a few days, or even a few months (WHO 2009). Flooding also spreads diseases by causing the overflowing of sanitation systems such as pit latrines and septic tanks, causing the contamination of surface and groundwater supplies (Satterthwaite 2008).

In the long term, raised groundwater levels due to more frequent and intense precipitation events decrease the effectiveness of purification processes that occur naturally, and so this will reduce the removal of pathogens from water supplies and increase the risk of infectious water-borne diseases (WHO 2009).

Mozambique is one example of a country with a tropical climate. Heavy rains and cyclones in Mozambique in 2000 led to the worst flooding in 50 years, causing the wreckage of the capital city of Maputo, and the disruption of urban water and sanitation services. There was an outbreak of cholera and dysentery, and over 1 million people were affected (Douglas et al. 2008). In addition, the flooding of 3000 septic tanks in the cities of Chokwi and Xia-Xia in Mozambique caused widespread contamination (WHO 2009).

What can be done to increase the resilience of urban water and sanitation infrastructure to climate change?

As in every case, strong governance is essential (Oats et al. 2014). Governments tend to have a weaker role in low-income and some middle-income nations, and fail to serve the whole urban population. Many major cities in low-income African nations don’t have sewer systems or a private piped water supply, and a lack of sufficient waste collection services means that waste clogs up drains, so light rainfall is enough to create localised floods (Satterthwaite 2008).

Governments are often reluctant to extend urban integrated drainage systems to informal settlements, because doing so legitimises the slum areas, but this worsens the impacts of rainfall events. In Lagos, Nigeria, the Iwaya/Makoko slums in low-lying areas are experiencing more frequent flooding and peak flows are increasing. The drainage system is inadequate to cope with the water levels, and floodwaters often bring organic waste into homes.

Waste accumulation in Iwaya/Makoko (source: Nnaji 2016)

But the locals aren’t helping themselves: waste that is dumped in the lagoon by residents blocks drains. Therefore the flooding problem would be solved by a joint effort of governments introducing proper drainage facilities, and local residents regularly clearing the drainage channels (Douglas et al. 2008).

The inseparable link between water, sanitation and hygiene (WASH) and climate change is often overlooked. For example, shouldn’t the UN Framework Convention on Climate Change be working together with the Sustainable Development Goals to formulate appropriate policies? There needs to be better integration of climate change and WASH bodies on all scales to bring about the most beneficial WASH and climate adaptation plans (Whiting 2016).

A ‘development + adaptation’ approach is a win-win for governments, because their engagement in climate change adaptation will also generate development benefits (Satterthwaite 2008). Improving the quality of and access to WASH facilities is a key part of poverty reduction as it creates a number of knock-on effects: better health increases productivity, which has positive effects on education and income.

On a local scale, this overlap can be characterised in urban institutional action to reduce climate change generated hazards, such as extending piped water supply, introducing better waste collection, changing the design of latrine systems to prevent them from overflowing in flood situations, and improving drainage (Satterthwaite 2008, Oats et al. 2014).

Of course this does come at a price: it is estimated to cost between US$1.05bn and US$2.65bn annually to adapt current urban water infrastructure in Africa to be more resilient to climate change (Muller 2007). But this is paid back in the long run; investing in water and sanitation projects generates at least US$4.3 for each dollar invested (Hutton 2012).

Social enterprises can also work to improve water supplies through new technologies. One example is the joint initiative of USAID’s WA-WASH programme and local organisation ANIMAS-SUTURA in Niger to endorse Aquatabs, an inexpensive water purification tablet which can purify 20 litres of water for only $0.02. This venture has been highly successful, and over 10 million tablets have already been sold (USAID).

In terms of WASH and development, ‘climate change is widely perceived as a threat rather than an opportunity’, but the threat of climate change can trigger widespread development and health service benefits (WHO 2009). It forces governments to focus on sustainability when planning sanitation facilities, and so new WASH infrastructure will be more resilient, long-lasting, and equitable.