Africa's cities are booming. But they will be hit hardest by climate change. In interviews with 30 urban Africans, including informal waste pickers and UN climate scientists, DW looks at how four big and fast-growing cities are adapting: Lagos to scorching heatwaves, Kampala to rising waste, Cairo to potentially looming drought and Dar es Salaam to choking traffic.

Skipping class to address leaders of some of the world's most powerful cities, 22-year-old Hilda Nakabuye called on the room of mayors to stand in solidarity with young people fighting for the planet.

"I am a victim of this climate crisis and I am not ashamed to say so," said Nakabuye, a student from rural Uganda who now lives in Kampala, at a climate conference in October. Her voice cracking and eyes wet with tears, she recounted how her family had sold its land and livestock after heavy rains and fierce winds washed away crops, and drought dried up wells. "When the money was over, it was a question of survival or death."

The mayors rose to their feet.

Nakabuye, who started campaigning for the environment in 2017, is one of thousands of young Africans who have taken to the streets demanding governments act — urgently — against global warming.

Africa's urban population is set to double by 2050 and its citizens, three-quarters of whom are below the age of 35, are readying themselves for a future of scorching heat — where water is scarcer, air dirtier and floods hit harder and more often.

Hilda Nakabuye joined Greta Thunberg's global youth climate movement after two years campaigning for the environment.

© Photo: Emmanuel Balemezi

Many are witnessing such effects already. Two in three Africans who have heard of climate change say it is causing a decline in the quality of life in their countries, a pan-African survey of 45,000 people by Afrobarometer found. About half say they've seen extreme weather become more severe in the last decade.

"I'm lucky that I'm still surviving," Nakabuye said at the World Mayors Summit. "I will not take this for granted because people are dying every day."

Yet as the climate crisis accelerates across the planet, it is Africa's cities that are most at risk. Here's how they compare to cities across the world:

Africa is home to three of the world's megacities. The populations of , and Kinshasa have already gone beyond 10 million. Luanda and will join them in a decade. Cities such as , Bamako and Ouagadougou — whose populations are in the low millions — are some of the world's fastest-growing.

Against this backdrop is a deteriorating climate that suggests a period of increasingly extreme weather. As people flock to cities in search of prosperity, and infrastructure struggles to keep pace, citizens are plagued by overflowing waste and toxic traffic, too.

Amplified by urbanization, climate change in Africa is a "mega strain and mega challenge," says Maimunah Mohd Sharif, executive director of UN Habitat, the United Nations agency for human settlements."We have to really change now. Otherwise I think we have no future."

Hay stubble burning north of Cairo, suffocating the polluted city with smoke.

© Photo: AFP/Getty Images | Khaled Desouki

Cyclone Idai devastated Southeast Africa in March with floods and rain.

© Photo: picture alliance / AA | Gokhan Balci

Rising seas and poor housing leave informal settlements at risk in Lagos.

© Photo: AFP/Getty Images | Stefan Heunis

But cities are responding.

"We don't want to keep singing the song that Africa is the most vulnerable to the adverse impacts of climate change," says Anthony Nyong, director of climate change at the African Development Bank. "[This] is true, but we also know that Africa has opportunities that it can explore to chart a low-carbon, climate-resilient development pathway."

As the environment breaks down, and populations swell, how are Africa's biggest and fastest-growing cities adapting?

Temperatures in Lagos are rising — fast.

The sprawling Nigerian megapolis is home to 13 million people, according to the UN, but government estimates put the figure as high as 20 million, depending on where the city's boundaries are drawn. By the end of the century, scientists project Lagos will have the most people exposed to extreme heat of any city in Africa. Climate change will make heatwaves in Lagos longer, stronger and more common.

Hotter weather can exacerbate some mental health conditions and makes even mundane tasks — such as walking to work or going to bed — draining.

Heatwaves hit children, elderly people and the sick hardest. But fit young adults who work outside, such as builders and fishers, are also at risk. Extremely hot weather can worsen heart, lung and kidney disease. At worst it kills.

Here's how high temperatures are set to rise.

Built across a lagoon and cooled by an Atlantic breeze, Lagos should expect lower temperatures than the rest of Nigeria. But an "urban heat island" effect counters this. Cities tend to be hotter than surrounding countryside because infrastructure, such as concrete buildings and tarmac roads, soaks up heat generated by the bustle of human activity — cooking, driving, industry — and steadily releases it during the night. This can spell temperatures more than 7 degrees hotter in Lagos than in rural areas surrounding it.

And people in slums feel that heat most.

Poor, dense housing makes heat stress worse. Built with roofs of corrugated iron and walls of plastic sheet, makeshift homes act like greenhouses, trapping heat under baking sunlight. In cities from Kinshasa, Democratic Republic of Congo, to Bamako, Mali — where more than half the population live in informal settlements — crowding leaves little room for wind to move.

Moses Anjola, a Lagosian community blogger, lives in a small box-like structure made from wooden planks, tarpaulin, nylon and cardboard.

Like many in the city, he is wary of government efforts to develop informal settlements. Anjola has already been evicted from one slum. He had been sleeping on wooden boards in the rain before he "jam packed" materials together to create a small shelter.

Anjola is not alone. Authorities left 30,000 homeless and 11 dead when they bulldozed waterfront slums in 2016 and 2017 in a series of mass evictions that cited environmental and safety concerns, according to Amnesty International.

Plagued by demolitions, and at risk of heat stress from overcrowding and poor housing, slum-dwellers such as Anjola have few ways to escape torturous temperatures. They are often the lowest earners and cannot afford air-conditioners and refrigerators. Without clean water, they are more likely to drink from polluted streams to stay hydrated.

Some struggle to even turn to trees for shade, because residents fell them for firewood and building materials.

The Otodo Gbame fishing community was razed in 2016.

© Photo: AFP/Getty Images | Pius Utomi Ekpei

Across Africa, countries and cities are planting trees to combat climate change. Ethiopia made headlines in August by saying it had planted 350 million trees in half a day and the African Union has spearheaded a project to plant a green wall of trees across the Sahara desert. To fight the urban heat island effect, Lagos pledged to plant 10 million trees by 2020.

Lagos state's Environmental Protection Agency says authorities have criminalized indiscriminate tree felling and that 8 million of the pledged trees have already been planted.

Reluctant to wait for trees to grow and already struggling with hotter days and sleepless nights, some Lagosians are building their way out of heatwaves.

Papa Omotayo, an architect and founding member of the African Alliance for New Design, is building a training center for vulnerable children in Gbagada, a Lagos suburb. Compressed earth bricks, a wing-shaped roof and polystyrene insulation keep indoor temperatures and costs low, he says, and avoid the need for air-conditioning.

The compressed earth and passive ventilation of the center draw on Nigerian architectural traditions, says Omotayo.

The passive cooling Omotayo uses is a form of design that diverts thermal energy that accumulates in buildings into "heat sinks." This can mean digging deep into cool ground or using the shape of a construction to divert airflow. Buildings made of rammed earth — a mixture of local clays, sand and soils compressed together — regulate temperature by heating slowly during the day and releasing energy during the night.

The return to traditional designs for passively cooled buildings is part of a wider trend echoed across West Africa from Niger to Burkina Faso.

Good architecture is made locally and not imported from cities like New York and Dubai, says Christian Benimana, architect and founder of the African Design Center. "Unfortunately the general thinking around responding to the fast growth of cities in Africa tends to focus more on the latter."

In a city where 60% of people live in informal settlements, poorly served by infrastructure, residents have few options for disposing of refuse and sewage. "Many homes also do not have waste collection points, and some can't actually afford paying us or the companies to collect their waste," says Majid Muganzi, a former garbage truck worker who is now a self-employed picker. "They wait at night when it's dark and dump it by the roadsides and sometimes in drainage channels."

Kampala collects between half and two-thirds of the waste it creates and trucks it to the city's single licensed landfill: Kiteezi. Sprawling over an area of 14.5 hectares (36 acres), Kiteezi's mountains of waste grow by between 1,000 and 1,400 tons each day. Kampala City Council Authority (KCCA) says the overflowing landfill should have reached the end of its life a decade ago.

But for some in Kampala, the dump is a lifeline.

Kiteezi's waste sits at a dangerous intersection between urbanization and climate change.

As Kampala has grown, and poorer residents have settled in wetlands at the bottom of its hills, the city has lost natural drains that used to soak up rain. The World Bank estimates Kampala's wetland area fell from 18% to 9% between 2002 and 2010, leaving water with fewer places to escape.

But waste — stored in open landfills or littered on the ground — also poses a threat to drainage. It can easily blow into and block streams and channels. During storms, water that might have otherwise drained away has instead flooded the city's low-lying informal settlements.

And climate change means heavy rains will get heavier.

This combination of waste, poor housing and stronger storms will leave Kampala's urban poor increasingly exposed to flash floods during the rainy season, risking cholera and diarrhea. "Once you have waste mixing with water the population is consuming, it definitely increases the chance of water-borne diseases," says Phoebe Shikuku, climate expert at the International Federation of the Red Cross and Red Crescent. "It's a cycle where one vulnerability leads to another impact and another vulnerability."

Kiteezi's waste is not secure.

© Photo: Edward Echwalu

To collect the waste the city currently generates, KCCA says it needs 65 trucks — but only has 14 that are fully operational and six older ones that sometimes join the fleet. KCCA relies on private companies to help it collect waste and transport it to Kiteezi.

But some residents in poorer districts can't afford the fees these companies charge."Many families struggle to afford basics like food and shelter," says Muganzi. "Waste is the last thing they can think of."

Because of this, private companies are incentivized to collect from wealthier neighborhoods, leaving KCCA's few trucks scrambling to pick up the rest. They will come under more strain as Kampala and its waste grows.

Yet even as authorities struggle, Kiteezi's informal workers, such as Namuddu, the waste picker, and Amon, the waste dealer, help keep the city clean.

"The environmental contribution of these informal waste pickers is massive," says David Dodman, director of human settlements at the International Institute for Environment and Development. "They make sure things that can be reused are reused and things that can be recycled are recycled."

The plastic from which they make most of their money is only a fraction of the waste dumped on Kiteezi's mountains. Uganda is one of 34 African countries that has banned or taxed single-use plastics, though these rules are not always enforced.More pressing is organic waste, such as food and sewage.

On a small scale, enterprising Ugandans have capitalized on this. Some businesses in Kampala collect, dry, and compact organic waste — from Kiteezi, local neighborhoods or directly from businesses — into "briquettes." These blocks of solid fuel can be burnt for energy, replacing charcoal and firewood. Others are trying to recover nutrients by composting it into fertilizer. In 2017, a Ugandan tech firm created an app called Yo-Waste to link garbage collectors with customers. It wants to become the "Uber for waste" and says it works only with haulers who recycle.

Garbage truck struggle to collect Kampala's waste.

© Photo: Edward Echwalu

The authorities have made progress, but it is not enough, says Najib Bateganya, an environment official at KCCA. Between 2011 and 2017, KCCA says it doubled the share of Kampala's waste it collected, bringing the total to 64%.

"They are still very much excited with engineering solutions to waste," says Shuaib Lwasa, associate professor of climate change adaptation at Makerere University. "Get more trucks, get more grants, get more support, get landfilling. If 88% of the waste were organic — to take their figure — you'd definitely come up with a system to turn it into nutrients and energy."

But KCCA says it educates Kampalans to reduce dumping and encourage use of private waste collectors, and, to ease pressure on Kiteezi, has acquired a site to recycle waste and recover nutrients and energy.

Even so, says Bateganya, KCCA cannot afford modern waste treatment facilities, and private firms don't invest in new capital themselves because recycling has low profit margins. "Waste is a development issue, like health [or] education, it's not just a business. If you take it as a business, you make it costly for the people, and it cannot work."

When drought struck the Levant 3,200 years ago — contributing to famine, displacement and war — Egypt sent grain to former enemies and bred hardy cattle resistant to heat. The pharaohs' actions were not enough to prevent the fall of neighboring empires, but archaeologists say their policies helped prolong the life of Ancient Egypt.

Today, the North African country is again grappling with how to adapt to a lack of water.

Egypt is home to much of the Nile, Africa's longest river, whose fertile banks nurtured some of the world's first cities. Forty-five of the 50 densest cities in Africa are on the Egyptian Nile, data from research platform Africapolis shows. For millennia, Egyptians have relied on the Nile to drink and feed crops.

But its waters surge from springs over which Egypt has little control.

Water is hard to come by in Egypt, which receives little rainfall and is mostly desert. Already below the UN's threshold for water poverty and on its way to "absolute water scarcity," Egypt is the country with the sixth-least water per person in Africa.

In hot and dry years with little rain upstream, the GERD's effects on the Nile could be catastrophic.

Egypt says the GERD will limit water for its growing population, which at almost 100 million is the third-largest in Africa, behind Nigeria and Ethiopia. Egypt and Ethiopia have yet to agree how much water the latter will allow through the dam as it fills, and over what period of time. Bitter negotiations regarding water rights between Egypt, Sudan and Ethiopia have threatened to flare into war as recently as October.

Even as it reduces flow, the dam could help long-term water security by storing water in wet years and releasing it in dry ones, if the countries agree to share it fairly.

Yet climate change, which is set to increase evaporation and make rain patterns more erratic, will leave less to share out.

Egypt's cities have relied on the Nile's water for millennia.

© Photo: picture alliance/AP Photo | Amr Nabil

In Greater Cairo — a sprawling metropolis of 20 million people that is predicted to grow by a further 9 million by 2035 — population growth will strain the city's ability to cope.

Residents of poorer suburbs bear the brunt of water scarcity.

Suzan Ghany, a journalist, lives in Kafr Tuhurumis in Giza, a city within Greater Cairo. Her daily life is restricted by a pipe system that works only for seven hours from the early morning and total water shutdowns that can last weeks.

"When the water returns, you fill bottles, pans, anything you could find," says Ghany, who spends an hour at a time filling bottles to use later. She filters water for cooking and drinking and uses unfiltered water for cleaning, washing dishes and in the bathroom.

In Kafr Tuhurmis, 786 households are not even connected to the public water network, official data shows. They rely mostly on bottled water, wells and pumps. Both those with mains supply — such as Ghany — and those without have taken matters into their own hands.

Most houses on the street have drilled for groundwater and use motor pumps to compensate for low pipe pressure, says Ghany. But when residents of her building took that step, she says, the water was not suitable for human use. Industrial wastewater and agricultural runoff plague the Nile, with factories and farms offloading pollutants that sully the river and leach into groundwater. "You can say [drilling for groundwater] is a solution, but at the same time it is not. You have water all the time, but it's polluted water."

Some houses in Kafr Tuhurmis are not connected to the water mains.

© Photo: Hazem Abdul Hameed

Suzan Ghany is connected but only has access for seven hours a day.

© Photo: Hazem Abdul Hameed

She adapts her daily routine to the water supply.

© Photo: Hazem Abdul Hameed

In October, Egypt's Ministry of Water Resources and Irrigation hosted Cairo Water Week, an international conference responding to water scarcity. The Egyptian government is focusing efforts on infrastructure, farmers and families.

"Egypt has caught up tremendously in the last few years with regards to scarcity," says Helmy Abouleish, director of SEKEM, a farming and research organization that invests in sustainable agriculture and has converted desert near Cairo into fertile oasis. "For the first time the government is aggressively addressing this issue in public."

Egyptian authorities are building sewage plants to recycle water and desalination plants to remove salt from brackish groundwater and the sea. In Cairo, they are installing water-saving taps in public spaces, government buildings and even mosques, where washing rituals take place several times a day.

They are also trying to fix leaky pipes and inefficient taps.

Heatwaves in Cairo make water scarcity worse.

© Photo: imagoZUMA Press

But distributing water fairly is as important as reducing wastage, says Harry Verhoeven, a Qatar-based researcher who has written a book on the politics of the Nile. Egypt relies on the river for 97% of its water needs. "What the number veils, of course, is how that water is allocated internally."

Eighty percent of Egypt's water is used in farming, with inefficient practices such as flood irrigation compounding shortages, as well as water-intensive crops such as rice, wheat and tomatoes. Despite pressing water scarcity, Egypt was a net exporter of rice until 2016, after which it intermittently banned exports. Official data is not publicly available, but a report in 2018 by Transparency International, an NGO, found that the Egyptian military has "unrivalled power over public land" and owns, through an agency, several of the country's major water and agriculture firms.

"As long as people are unwilling to talk about distributional questions — and the ways in which water and environmental issues more broadly are linked to political power — [it] is going to be very difficult to make any progress," said Verhoeven.

Home to 6 million people and growing at breakneck speed, Dar es Salaam has sprawled — unplanned.

Seven major roads, radiating out of the city center, connect Dar's inhabitants on the outskirts with work and services in the city center. A lack of official public transport leaves many commuting in private cars and thousands of daladalas — informal minibuses — which overwhelm roads.

Idling in traffic jams, cars and daladalas fill Dar's streets with fumes that make air toxic to breathe. Many vehicles are second-hand and in poor condition.

Salum Iddi, a builder who works at sites across Dar, remembers slow, packed journeys when he used to commute into town in daladalas. "The thing that irritated me on the road was when you came from home and went to work, you would be on the road for so many hours — three, four hours — because of the traffic jams."

Dar's congestion is a question of security as well as climate.

In 2016, after more than a decade of planning, Dar es Salaam started to run a modern transport network. Rather than invest in an underground metro or light rail system such as those familiar to big cities in Europe and North America, the engineers in Dar took a simpler approach: buses.

Cheaper and easier to build than rail, bus rapid transit (BRT) has the capacity to transport huge numbers of people in cities with little capital or access to finance. It has segregated lanes that keep buses away from cars and daladalas. About 170 cities in the world run BRT systems and, in Africa, 20 are in various stages of development.

In Dar, the World Bank and African Development Bank helped the Tanzanian government to finance a BRT system known as the DART. The first of its six planned phases started running in 2016.

By taking some daladalas and private cars off the road, the DART also reduces congestion. Experts say the drop in traffic has noticeably cut pollution.

"The older buses in Dar es Salaam that the BRT replaced were heavily polluting, smoking buses," says Chris Kost, Africa program director at the Institute for Transportation and Development Policy, which was involved in building the DART. "The BRT system was able to replace 3,000 of those vehicles with 140 ... [different] vehicles that have much lower emissions."

But the DART is not open to everybody.

While Tanzania has enjoyed high and steady economic growth over the last decade, half of all Tanzanians live on less than $2 a day, according to the most recent World Bank data. BRT tickets cost about $0.28 on the main roads, while a daladala journey along the same route would cost up to $0.22, experts say.

A review by the World Bank in 2018 described "teething problems," including long queues and passenger discomfort. "It has been overwhelming," says Ronald Lwakatare, CEO of the DART.

More troubling, for some residents, is the hit to jobs that has come with environmental gains. Despite provisions to retrain some daladala drivers, the DART has pushed many out of business. A similar system in Accra, Ghana, led to confrontations with informal minibus drivers that contributed to dwindling passenger numbers and buses being grounded.

Experts say engaging with transport workers and including them in planning is essential for making BRT systems work.

"You cannot say the BRT is entirely negative or entirely positive," says Nathalie Jean-Baptiste, an architect and founder of CityLab Dar es Salaam, a research platform that looks to sustainably develop African cities. "It has changed the way transport occurs in Dar ... There's always a shift, some sort of stress, but users adapt."

A construction site in Kigali. The Rwandan capital has been dubbed the "cleanest city on the planet."

© Photo: imagoZUMA Press

Time is running out. Temperatures have risen by about 1 degree Celsius since the Industrial Revolution and world leaders have pledged to limit the rise to well below 2 degrees. If humans continue releasing greenhouse gases into the atmosphere at current rates, temperatures will increase about 3 degrees by the end of the century.

The hotter the planet gets, the more African cities will struggle. Greater warming could test the limits of how many trees Lagos can plant in the city and how much Cairo has to invest in desalinating sea water. The rise in storm strength could — through floods — ground Dar es Salaam's bus fleet regularly enough that it can't turn a profit, and outpace Kampala's efforts to clean up waste that clogs drains.

There is no on/off switch for the climate crisis.

To limit its effects, scientists say world leaders must cut emissions — and that includes those generated in cities. A hundred cities drive 18% of global CO2 emissions, a study into the carbon footprints of 13,000 cities found in 2018, and those with the highest emissions per person are disproportionately in North America, the Middle East and Australia.

That has left policy makers choosing, at times, between climate mitigation and economic growth.

"High amounts of energy would be needed to develop, and most of it would be sourced from fossil fuels," says Precious Akanonu, research fellow at the Center for the Study of the Economies of Africa. Four in 10 Africans live on less than $2 a day, World Bank data shows, and just half of Africans had access to electricity in 2017, compared to a global average of 88%. "I don't think it's proper for African countries to be denied their right to develop."

Subsidies from the international community could offset the extra costs that green energy requires, says Akanonu. "Without the subsidy, if [African governments] go and invest in a more expensive source, it robs the country of money that would be used for other development needs."

Rich countries have promised poorer ones $100 billion a year in climate finance by 2020. But with little agreement on what counts as adaptation funding — such as the difference between grants, loans and private investment — and inconsistencies in reporting and tracking the money, receiving countries question whether it will be enough.

"Africans should be supported to harness the abundant renewable energy resources they have," says Nyong, the African Development Bank climate expert, "so we don't go back to the sort of development paradigm — that the earlier developed countries have taken — that has put us in this situation through very high emissions. We can do it differently. We can do it better."

A South African man rebuilds his house after a fire in Masiphumelele, Cape Town. Crowded informal settlements are particularly vulnerable to disaster.

© Photo: AFP/Getty Images | Wikus De Wet

Survivors have been forced to rebuild after Cyclone Idai lashed Mozambique with winds of nearly 200 km per hour.

© Photo: picture alliance /dpa | Nic Bothma

Asked if African cities were doing enough to adapt to climate change, most people DW spoke to said no. African climate scientists, architects and engineers said some municipal governments had adopted successful adaptation policies, but the pace of change was not fast enough — particularly to protect the most vulnerable people in cities.

"In a nutshell, what is working well is climate change awareness," says Martin Manuhwa, president of the Federation of African Engineering Organizations. "What isn't working well is climate-resilient infrastructure design."

"A lot is happening at the community level that needs to be scaled up at the municipal to really have an impact," says Ebenezer Amankwaa, research fellow at the United Nations University Institute for Natural Resources.

But experts also say Africa is in a good position to leapfrog the rest of the world because much of its infrastructure has not yet been built. "We can quickly catch up and learn from the mistakes other continents [made] and build resilient infrastructure for the future," says Manuhwa.

Africa is the only region in the world where the number of young people is rising, and, by 2050, half its population will be under 25 years old. Speaking at the climate conference in Copenhagen, Hilda Nakabuye, the Ugandan activist, told world mayors her generation is one that is scared — but ambitious, persistent and united.

"Through endless fights and sacrifices we hustle our way, because this is our future."