Category: Water

New project supports climate adaptation and resilience for Pacific Islands

New project supports climate adaptation and resilience for Pacific Islands

By Will Bugler

Fifteen Pacific island countries are part of the newly launched Pacific Adaptation to Climate Change and Resilience Building (PACRES) project under the Intra-African Caribbean Pacific (ACP) Global Climate Change Alliance Plus (GCCA+) Programme funded by the 11th European Development Fund’s (EDF). The EUR 12 million project aims to strengthen adaptation and mitigation measures at the national and regional level and support partner countries in climate negotiations and in implementing the Paris Agreement on climate change.

Jointly implemented by the Secretariat of the Pacific Regional Environment Programme (SPREP), the Pacific Community, the Pacific Islands Forum Secretariat (PIFS) and the University of the South Pacific, the project will also have a disaster resilience component. Some of the activities of the project, according to SPREP, include knowledge sharing, strengthening of networks, and trainings and research opportunities.

An inception and planning meeting for the project was held from 1-3 April 2019 at the SPREP Campus in Samoa.

The Cook Islands, the Federated States of Micronesia (FSM), Fiji, Kiribati, Niue, Nauru, Palau, Papua New Guinea (PNG), the Marshall Islands, Samoa, Solomon Islands, Timor-Leste, Tonga, Tuvalu and Vanuatu participate in the project.

Photo Credit: Gemma Longman

Ocean productivity at risk as climate warms

Ocean productivity at risk as climate warms

By Tim Radford

Runaway climate change will alter the pattern of ocean productivity and circulation and play perhaps irreversible havoc with fish catches.

LGlobal ocean productivity – the annual bloom of algae and the cornucopia of molluscs, shrimp, krill, squid, fish and marine mammals that depend on this flowering of the blue planet – could be in serious decline by 2300,  thanks to climate change.

The harvest from the North Atlantic could fall by almost two thirds. The decline in the Western Pacific could drop by 50%. The overall productivity of the oceans from pole to pole will be at least 20% less.

Global warming that is already melting the ice caps and increasingly making the seas more acidic has been blamed for changes in fishery hauls and damage to reef ecosystems.

But the latest study looks not at the immediate consequences of profligate human combustion of fossil fuels, but at the very long-term consequences of turning up the planetary thermometer.

Scientists report in the journal Science that three centuries of continuous rise in carbon dioxide levels in the planet’s atmosphere, as a consequence of fossil fuel combustion, could raise global average temperatures by 9.6°C.

This is ten times the warming already observed. It will change wind patterns, melt almost all the sea ice and increase ocean surface temperatures.

And with this increase in temperature comes change in the growth of phytoplankton, on which ultimately all marine life depends. There will be shifts in ocean circulation that will take nutrients from the surface and deposit them in the deepest waters.

Antarctic waters could become richer in nutrients. But the world’s human population is centred in the northern hemisphere. “Marine ecosystems everywhere to the north will be increasingly starved for nutrients, leading to less primary production by phytoplankton, which form the base of ocean food chains,” said Keith Moore, an earth system scientist at the University of California, Irvine, who led the study.

“By looking at the decline in fish food over time, we can estimate how much our total potential fisheries could be reduced.”

Research of this kind is based on computer simulation of an entire planetary ocean system over the next 280 years. Leaders from almost all the world’s nations vowed in Paris in 2015 to contain global warming, and other studies have shown that world commercial fisheries would benefit from such action.

Delayed response

But time is running out: the oceans have yet to respond fully to the greenhouse gases that have already built up in the atmosphere in the last century or so.

“The climate is warming rapidly now, but in the ocean, most of that added heat is still right at the surface. It takes centuries for that heat to work its way into the deeper ocean, changing the circulation and removing the sea ice, which is a big part of this process,” Dr Moore said.

“This is what’s going to happen if we don’t put the brakes on global warming, and it’s pretty catastrophic for the oceans.

“There is still time to avoid most of this warming and get to a stable climate by the end of this century, but in order to do that, we have to aggressively reduce our fossil fuel use and emissions of greenhouse gas pollutants.”

This article first appeared on the Climate News Network.

Photo by Lalo on Unsplash

Big storm clusters are on the increase – what this means for hurricane hotspots

Big storm clusters are on the increase – what this means for hurricane hotspots

By Anitha Karthik

Melting glaciers, rising sea levels, global warming and violent storms: the effects of climate change are well documented. But a growing weather trend that has caused much concern is storm clustering – when three (sometimes more) hurricanes or typhoons group together in a short space of time, gathering strength and unleashing even greater devastation.

The development of a tropical depression – a low pressure area with thunderstorms and winds below 39mph – to a tropical storm that attains hurricane strength in less than six hours, shows how quickly these things can intensify.

But increased frequency is also a trend, as storms follow each other in quick succession. Those who question the existence of climate change should look at the global hurricane history, or even the hurricane pattern in their own country. If we look at these storms, patterns of increasing intensity and frequency clearly demonstrate how climate change is having a direct impact on the way hurricanes behave.

In developed countries coastal residents in affected areas are keenly aware of these hazards and respond well during emergencies by liaising with local agencies and heading to designated shelters during evacuations. But this is not the case in developing and underdeveloped countries, although basic response awareness exists through devastating experience and a degree of public information.

Predicting the big ones

Thanks to advances in hurricane forecasting and hindcastingtechniques, situations like the Galveston hurricane in 1900, which struck the Texas coast without any official warnings, are happily a thing of the past.

The weather prediction models of the National Hurricane Center and the European Centre for Medium Range Weather Forecasting are able to plot the likelihood of impending hurricane paths – known as the “cone of uncertainty” – five days in advance, and are generally accurate.

But the real issue is how prepared we are around the world for the increasing frequency of hurricanes and their terrifying “gang” version, hurricane trios. This violent onslaught of hurricane-strength storms batters communities and destroys buildings and infrastructure from the US to the Caribbean to South-East Asia. But should communities on the coast stay and defend, or retreat altogether?

A deadly trio of hurricanes from 2018 heading across the Atlantic. NASA

Hurricane season

Hurricanes hammered the Atlantic from 2016 and 2018, including the Category 5 Matthew (2016), the Harvey-Irma-Maria trio (2017), which registered Category 4, 5 and 4 respectively, and Category 4 Florence and Michael (2018). This not only revealed the rising trend in intensity and frequency, but also alerted the world to the phenomena of clustering.

Critically, predicting the path of a hurricane depends on forecasting the dynamics of its intensity. Understanding the factors that contribute to the sudden changes in the strength (or weakening) of a hurricane is crucial. Changes in wind direction, interaction with the land at the coast, and ocean temperature and depth all play their part in altering the intensity of a hurricane that is highly sensitive to even slight changes.

In general, the accuracy of predicting the way a hurricane intensifies and then re-intensifies in less than 24 hours is more challenging than predicting its path. But these dynamics are the underlying factors which compound the threat of hurricane frequency. These dynamics are also capable of further altering storm surge characteristics by triggering coastal and inland flooding – such as abnormal rises in water levels – which often result in shocking devastation.

Hurricane Michael in 2018 was the perfect example of the importance of predicting how rapidly a hurricane has intensified before it hits the coast, in this case Florida. The predicted track of the storm was almost accurate but its intensity was more difficult to assess.

The National Hurricane Center forecasted Michael’s path by issuing a five-day cone of uncertainty advising of sustained winds of 65mph. However, the sudden change in the storm’s dynamics changed a Category 1 hurricane to a Category 4 with winds of 155mph. This underscores the uncertain and variable nature of hurricane prediction.

Hurricane Michael after it made landfall in the Florida panhandle. NASA

Building on sand

Despite these emerging and changing weather-related risks, residential and public buildings are still going up on affected coastal areas. Recent research in China identified a tsunami that swept away the present-day coastal province of Guangdong in 1076AD. It means storm-related surges have been documented in the region for more than 1,000 years – yet still building and expansion goes on heedless of the risk.

This is almost the same situation for all vulnerable coastal cities. For instance, Florida has hundreds of thousands of coastal residents living in Low Elevation Coastal Zones – land that is less than ten metres above sea level and within 200km of the coast – but yet again construction there continues despite the threat of hurricanes every season.

Developers are already conceiving storm-resilient buildings that can withstand winds of at least 200mph – a Category 5 hurricane. But it’s unlikely many have considered the compounded stress effect on structures having to continuously withstand hurricane force winds more frequently and in quick succession.

A mudslide in Ucab in the Philippines caused by Typhoon Manghut in September 2018. EPA

Building massive sea defences along vulnerable coastlines is practically impossible and isn’t a permanent solution to increasing coastal storm hazards. There is no point in risking lives by remaining, as storm clusters can be unpredictable. It is simply too dangerous, so evacuation is the only option. However, when it comes to coastal assets and investments, defending in a more appropriate and sensible way is required.

Some coastal cities are planning ahead. A recent development of extensive parks in Boston, US, aims to protect the urban shoreline infrastructure from flooding. And a 2009 studyrevealed the effectiveness of mangrove planting in coastal areas of India to protect the shoreline and reduce cyclone damage. But more practical solutions are needed, especially in more vulnerable developing regions, because cluster storms are not going away any time soon.

This article was originally published on The Conversation and was republished under Creative Commons Licensing.
Cover photo by NASA on Unsplash.
Water is a growing source of global conflict. Here’s what we need to do

Water is a growing source of global conflict. Here’s what we need to do

By Kitty Van Der Heijden and Callie Stinson

The most intensive drought ever recorded in Syria lasted from 2006 to 2011. Water scarcity hit households, businesses and infrastructure, while in the countryside crops failed, livestock died, and entire families moved to the country’s cities. The subsequent eruption of civil war in 2011 led to as many as half a million deaths, as well as massive migration flows to neighbouring countries and beyond, and untold misery. Syria’s war has been a tragic illustration of the central, driving role that water insecurity can play in instability and conflict.

This is no surprise. In 2017 alone, water was a major factor in conflict in at least 45 countries, including Syria. Its importance as a resource means that water-related insecurity can easily exacerbate tensions and friction within and between countries. It can be weaponized; nefarious actors can gain control of, destroy, or redirect access to water to meet their objectives by targeting infrastructure and supplies. Advancements in cyber attacks on critical infrastructure raise further concerns as to the security of water systems.

The World Economic Forum’s Global Risk Report (GRR) has listed water crises among the top-five risks in terms of impact for eight consecutive years. In the most recent version of the report, it remains nested among a cluster of other risks that are rated as having both a very high likelihood and a very high impact. These include extreme weather events, natural disasters, the failure of climate change adaptation and mitigation, man-made environmental disasters, biodiversity loss and ecosystem collapse, interstate conflict and large scale-involuntary migration.

These risks are increasingly interconnected. Failure to mitigate climate change could lead to more extreme weather events, ecosystem collapse and a greater likelihood of man-made environmental disasters. All of these can exacerbate food and water insecurity, which in turn can lead to human deprivation, and could make these and other risks like migration and conflict more likely in a negative feedback loop. Around two thirds of the world’s population, or 4 billion people, currently live without sufficient access to fresh water for at least one month of the year.

Further complicating the picture is the reality that securing water for food and economic activity will only become more difficult over time. As economies develop, their water consumption patterns shift and overall demand rises dramatically to meet the needs of food production, thirsty manufacturing and other industries, thermal power plants and households. However, water supplies are often damaged by poor management, pollution and over-consumption, in addition to supply-side reductions due to climate change impacts and the ecosystem degradation mentioned above.

Many of these drivers of insecurity can be seen in the Inner Niger Delta area of Mali, a marshy wetlands along a stretch of the Niger river. Disruptions to the Delta’s waters, for instance through the construction of two upstream dams, risk destroying fragile ecosystems and further destabilizing the entire region. Altering downstream flows can jeopardize traditional economic activities that underpin the viability of Delta fishing villages, destroying livelihoods and exacerbating social tensions such as intergenerational friction.

Combined with reductions in available farmland associated with rising temperatures and desertification, such environmental degradation risks further fuelling mass migration to the Malian capital Bamako and Europe. The journey is not a safe one, with criminalised trafficking routes that pass nearby between the West African coast and the Sahara. The history of radicalization in the region by extremist groups that have established themselves in northern Mali further illustrates the vulnerabilities facing the displaced and disenfranchised. People whose access to water is limited risk becoming increasingly marginalized, and a target for recruitment by radical groups. Water is critical to the region’s security.

The Inner Niger Delta illustrates the critical role that water insecurity can play in exacerbating other risks, and the necessity of holistic policy approaches. Unfortunately, water insecurity is not yet taken seriously enough by all actors, despite its central role in our economies and in human lives and livelihoods. In most scenarios, the true security threat caused by water insecurity is not a ‘water war’, but rather in its secondary impact on associated human security, that which can then exacerbate local, regional and international security threats.

It can impede or reverse economic development, and prevent countries from playing their art in achieving the Sustainable Development Goals. It can also affect the private sector, for instance by affecting critical parts of complex supply chains. Robust solutions to the water security challenge are critical for everybody from public policymakers and businesses to the wider public and the international community. A new generation of public-private partnerships can be part of the solution to such complex and interrelated risks, responding with urgency and innovation to manage the ‘less for more’ challenge of reduced supply and increased demand.

Advances in technology can play an important role in this new era of collaboration. Real-time data is already being used to generate insights about the interplay of risk factors, allowing the development of sophisticated early-warning tools. The Water, Peace and Security Partnership partnership, for instance, crunches vast amounts of data, using machine-learning and other technologies to identify patterns that indicate the high risk of a conflict situation developing. It does not simply flash a warning light, but points to the factors that need to be addressed through capacity-building and stakeholder engagement to mitigate any potential conflict.

The tool, presented to the UN’s Security Council in 2018, aims to build cohesion for collective action among diplomats, defence analysts, development and humanitarian experts and environmental scientists. Another partnership, Digital Earth Africa, is developing an open-access platform of analysis-ready geospatial data for public use that will enable African nations to track environmental changes across the continent in unprecedented detail, including flooding, droughts, soil and coastal erosion, agriculture, forest and land-use change, water availability and quality, and changes to human settlements.

Such insights can help governments, businesses and communities better understand and address the interconnected web of environmental risks, in particular the impacts of climate change. From variations in rainfall patterns to extended periods of extreme weather events, building resilience across agricultural, industrial and domestic water supplies is a key priority for increasing water security.

The complex challenges and impacts of water crises will certainly make it difficult to shift from the top of future global risk lists. But real progress can be made, especially through cross-sectoral partnerships and platforms that can engage with such complexity. The 2030 Water Resources Group, which works across a network of more than 600 partners to tackle the water supply-demand gap in 14 different geographies, is a promising blueprint for effective public-private cooperation.

Access to better data can bolster such collaborations and lead to more effective solutions, for instance through mapping water risk, and generating greater understanding of how physical water shortages affect societal tensions, political disruptions and cross-border migration. These are just a few examples of how the world is already developing the types of ‘next generation’ insights, tools and partnerships needed to tackle water insecurity. But what the Global Risk Report makes clear is that any solution needs to be underpinned by an increased awareness of the scale and interconnectedness of the water security challenge before us.

This article was originally published on World Economic Forum.
Cover photo by Ibrahim Rifath on Unsplash.
Cape Town has a plan to manage its water. But there are big gaps

Cape Town has a plan to manage its water. But there are big gaps

By Jasper Knight, University of Witwatersrand

The City of Cape Town – and southwest Africa more generally – experienced its worst drought on record between 2015 and 2018. With fresh rains as well as careful water management, the city has now emerged from this environmental and economic emergency.

The final consequences of the drought might never be known for certain. This is because the effects on groundwater depletion or biodiversity loss may not appear until years after the event. But the economic impact of the drought is more easily identified. Over 30,000 jobs have been lost in the agricultural sector in the Western Cape region, caused by a 20% decrease in agricultural production.

There are other consequences too, such as the impact on the city’s international reputation, as well as residents’ and policymakers’ experiences of water restrictions and the threat of “Day Zero”.

So what are the lessons learnt?

The City of Cape Town has recently released a draft strategy for water supply and management which aims to ensure safe access to water and sanitation for all the city’s residents, efficient water use, diversified water sources and shared costs and benefits by 2040. This strategy has been strongly informed by events of the past three years and is a bold statement of intent. As such, it sets a benchmark for sustainable development in the city and the wider region. The strategy is aimed at increasing usable water availability and managing that water better. But some elements are missing.

An uncertain future

Missing parts of the strategy include the uncertainty of future trends in climate, economic activities, population growth, water demand and infrastructure investment needs. Increasing water availability is easy in theory because it is based on balancing supply to need. But this water needs to come from somewhere.

Rainfall is becoming ever more precarious, groundwater aquifers are depleted, and river and dam water is already allocated. Desalinisation is an option. But this is expensive and has unknown environmental impacts.

Another option is water redistribution. In the recent drought, water was diverted from the agriculture sector to supply the city. But this had ripple effects on farming communities and economies. This approach is probably no longer sustainable.

There is also the option of reducing water demand. The new draft strategy doesn’t specifically mention managing demand – it makes vague reference to the need to use water wisely. It may be that the memory of water restrictions is too recent to discuss in this document. But water management is not just about supplying water, it’s about changing hearts and minds. These take much longer to change. For some Capetonians, the drought is over and normal business is resumed. For others, the spectre of Day Zero still remains.

And the plan doesn’t indicate that lessons have been learnt. For example, an innovative Water Map used by the City of Cape Town was able to “name and shame” excessive water users, but some township users were exempt from restrictions while other wealthy users largely ignored the water restrictions because they could afford to pay the resulting fines.

This kind of behavioural analysis is important when it comes to equitable planning and water management, and provides a rich source of data for drought epidemiology – Cape Town knows more about how its residents use water than most cities.

Emerging from disaster

Over the next decades, it’s anticipated that southern Africa will experience both higher average annual temperatures, in particular in summer. It’s also expected to have more variable and somewhat lower rainfall. Collectively, these climatic changes will result in greater water insecurity, irrespective of any changes in population, water demand or capacity of water infrastructure.

recent study shows that climate change has trebled drought risk in Cape Town. Future-proofing cities such as Cape Town to withstand water insecurity and drought conditions cannot be done without managing water infrastructure better. In South Africa, 56% of waste water treatment plants are not fully operational. This limits its ability to deliver on the future promises outlined in the City of Cape Town strategy document.

Water restrictions in Cape Town have eased over recent months. But persistent drought still exists elsewhere in the region, in small town rural communities where there’s a lack of water infrastructure, lack of access to dam water supplies and depleting aquifers. Addressing the future water problem for Cape Town should not be done at the expense of the wider region, and must be formulated as a national-scale strategy. This should be a government priority.

This article was originally published on The Conversation and has been republished under Creative Commons license.
Cover photo from Shutterstock.
Asia’s water supplies threatened by melting glaciers

Asia’s water supplies threatened by melting glaciers

By Georgina Wade

The ‘third pole’, encompassing the Himalaya-Hindu Kush mountain range and the Tibetan Plateau, is the planet’s largest reservoir of ice and snow after the Arctic and Antarctic. The frozen reservoir hosts the world’s 14 highest mountains contributing to an area roughly the size of Iceland. Additionally, its melt waters feed ten great rivers on which almost one-fourth of the world’s population depend.

But in recent decades this vital area has faced increasing risk from climate change. For the past 50 years, glaciers in the Himalayas and Tibetan Plateau have been shrinking with the Tian mountains having already lost one quarter of their mass.

The Hindu Kush Himalaya Assessment finds that even if carbon emissions are dramatically and rapidly cut limiting global warming to 1.5° C, 36% of the glaciers in the Hindu Kush and Himalaya range will be gone by 2100. The resulting meltwater is expanding surrounding lakes, leading to earlier peaking of river flow while shifting weather patterns have dramatically reduced precipitation in the Himalayas.

“This is the climate crisis you haven’t heard of,” said researcher Philippus Wester of the International Centre for Integrated Mountain Development (ICIMOD). “In the best of possible worlds, if we get really ambitious, even then we will lose one-third of glaciers and be in trouble. That for us was the shocking finding.”

Put together over the course of five years by 210 authors and including input from more than 350 researchers and policy makers from 22 countries, the Hindu Kush Himalaya Assessment is one of the most complete studies on mountain warming.

While it is known that temperature changes due to increased levels of greenhouse gases are amplified at higher latitudes, there is growing evidence that warming rates are also greater at higher elevations. In October 2018, the International Panel on Climate Change (IPCC) found that if greenhouse gas emissions continued at the current rate, the atmosphere could warm by as much as 1.5° C above preindustrial levels by 2040. Warming under this scenario would be detrimental to the Himalayas, with temperatures likely to warm by as much as 2.1° C. Additionally, the report found that global glacier volumes are projected to decline up to 90 percent this century from longer melt seasons, decreased snowfall and increased snowline elevations.

Mountain villages in Nepal are being uprooted by rising temperatures and less predictable rain patterns. Fertile land that was once used for growing vegetables has become barren. Just recently, the mountain village of Samjong had to move around 1,000 feet lower after their crops repeatedly failed due to water sources drying up. Despite the precautionary move, Pasang Tshering Gurung, a Samjong farmer, believes there is still cause for worry as landslides linked to increased flooding continue to thunder down hillsides. “We will be landless refugees,” he said. “How can we survive in the Himalayas without water?”

Cover photo by Arianna Flores Corral on Unsplash.
Climate change to cause havoc with Mediterranean water resources says European Commission

Climate change to cause havoc with Mediterranean water resources says European Commission

By Will Bugler

The Mediterranean will face mounting challenges to manage its water supplies as climate change drives droughts and floods according to a report by the European Commission. The report, which focusses on the effects of 2˚C of warming, indicates that there is likely to be a divide between central and northern Europe, which can expect more rainfall overall, and the Mediterranean which will suffer drought.

The study, which assumes that land use and water demand remains constant, shows that river flows in the Mediterranean are expected to fall overall, but the region will still experience extreme rain events that will lead to river flooding. This will pose considerable challenges for water dependent sectors such as agriculture. Spain, Portugal and Greece face severe droughts during the summer season which will limit the amount of water available for cooling heavy industry and energy plants.

Groundwater resources are also expected to fall limiting the region’s ability to abstract water and increasing costs. This, coupled with lower soil moisture content, could lead to crop failure and reduced yields. The situation in countries such as Spain is critical, with freshwater resources expected to be insufficient to meet local water needs under a 2-degree warming.

The report urges governments to take action to adapt to such climate impacts through integrated water management policies. Demand for fresh water will need to reduce considerably, through measures such as increasing irrigation efficiency, efficiency increases in cooling processes in industry and energy production, public water savings, a better management of water resources by, for instance, storing winter water in hydropower reservoirs for irrigation water use in summer.

Download the report by clicking here.

Cover photo by Andres Flajszer/Wikimedia Commons (CC BY-SA 3.0): Aqueduct in Los Monegros desert, Aragón, Spain.
Toward a flood-resilient Kolkata

Toward a flood-resilient Kolkata

By Elisa Jiménez Alonso

Kolkata’s flood forecasting and early warning system (FFEWS), supported by the Asian Development Bank (ADB), will be India’s first comprehensive city-level early warning system. Designed to provide forecasts and real-time updates using sensors installed in key points throughout the city, the system will enable informed decision making before and during disasters.

How the FFEWS works. Source: ADB.

The system includes a series of complementary components: weather forecasts; flood models for various intensities of rainfall; real-time information on key pump status, sump and canal water levels, actual rainfall, inundation levels, among others; and a messaging system to provide warnings and real-time information to city officials and citizens. The FFEWS will enable flood-informed urban planning, improve the flood awareness and safety of Kolkata’s communities, reduce economic losses and flood-impacts on livelihoods, and reduce the impacts of flood-induced traffic jams.

The system was designed with the people of Kolkata at its centre and aims to empower them so they can act quickly and appropriately to reduce flood risks. During the design phase key stakeholders were consulted to identify the best places for monitoring. Consultation with citizens and borough engineers helped identify locations for real-time data collection on rainfall and flood risk.

Since 2000, phased investments carried out through ADB-supported projects have already helped reduce Kolkata’s flooding problems by about 4,800 hectares, planned projects are expected to provide a further reduction of roughly 6,000 hectares. The projects are enabling the city to systematically expand the sewerage and drainage network in Kolkata, including flood-prone areas; increasing sewage treatment capacity; improving water supply through reductions in non-revenue water; managing solid waste; and increasing operational efficiencies and building capacity to better sustain the services it provides.

Download the full publication and learn more about the key features and benefits by clicking here.

Heavy rains and blocked drains: Nairobi’s recipe for floods

Heavy rains and blocked drains: Nairobi’s recipe for floods

By Sophie Mbugua, Climate Home News

Dirty flood waters, impassable roads and submerged slums have become the norm every time it rains in Nairobi, Kenya’s capital city.

In August, the authorities took drastic action, bulldozing around 2,000 buildings in the flood plain, including shopping malls worth millions of dollars. After a lull, they are due to resume demolitions this month, national media reports.

The ongoing October-December rainy season is on track to bring – mercifully – average volumes of water. Yet the city’s flood risk is rising, as climate change brings more extremes of rainfall. Experts tell Climate Home News better waste management, urban planning and warning systems are needed to protect its growing population.

Numerous informal and formal settlements without adequate sewerage and sanitation services edge onto the three Nairobi Rivers: Mathare, Ngong and Nairobi.

At Hazina village, one of 22 villages in south B division along the Ngong, the river chokes with refuse, making the water hardly visible.

“It’s the village’s dumping site,” Anne Keli, a 46-year-old mother of 12 tells Climate Home News. She has lived in the village for two decades and says flooding has been particularly bad in the past two years.

“The water reaches the village at a high force compared to previous years but gets stuck due to the plastics, paper bags and assorted waste in the river, blocking its flow,” Keli says. “Since we are on a lower area, the run-off from higher areas headed to the river has no place to go as the river is full. So, where else does it go? Into our houses.”

During the long rains in April, Keli’s family left their flooded home and camped in the county commissioner’s grounds. She lost around 30,000 Kenyan shillings ($290) worth of goods from the shop she runs less than a kilometre from the river.

The provincial administration made some efforts to clean the river during the flooding, but as soon as the rainy season ended it clogged up again, Keli says. “People keep building close to the river, reducing its size by day. People are asked to remove the structures with every flood but after the rains, everything moves back to normal.”

Kenya Meteorological Department (KMD) has installed more than 72 monitoring stations across the country in a bid to provide more timely and precise information.

Brian Chunguli, a county disaster management official, says a UK-funded programme will allow them to monitor live flooding levels from satellites and alert residents as waters rise.

“We hope to respond before flooding happens, and collected data will inform the disaster policy and interventions as we will compare long term data showing at what rainfall levels has certain areas flooded,” explains Chunguli.

Long-term projections of East African rainfall vary, with most climate models predicting heavier inundations as temperatures rise.

Mary Kilavi, the Nairobi County director of meteorological services, is mapping the areas likely to flood in Nairobi given a specific amount of rainfall. South B and South C on the Ngong river are hotspots, along with Mathare by the Nairobi river.

“We are using a model that simulates surface water flooding using previous city flooding data corrected over time,” she explains. “We want to find out with a specific amount of rainfall, which areas will flood.”

This will help the authorities to move beyond a reactive approach to systematic preparation, she says. “Since weather is given in probabilistic terms, systems don’t act fast. We will establish the probability of achieving the estimated flood causing rainfall, then with stakeholders, agree at what point to act, the actions to take and funds to be set aside for the actions.”

The solutions range from cleaning up waste to creating green urban spaces and changing land management upriver. Many of these face political, as well as practical, obstacles.

There is a directive against building within 30 metres of the riverside, for example, but it is haphazardly enforced. Many owners of the recently demolished structures insisted they had permits to build there.

“It requires funds and land to relocate and rebuild the structures amid political interference, as area politicians incite the residents not to move,” says Barre Ahmed, assistant county commissioner for Starehe sub county.

Dr Lawrence Esho, chair of the Kenya Institute of Planners, calls for a drainage master plan to cover the entire metropolitan area.

“We have a flooding crisis but the issue is bigger than the illegal buildings. It is more of the uphill destruction of land which we are doing nothing about, too much concrete pavements aggregating the run off flow, blocked drains and climate change,” says Esho. “Over the last 20 to 25 years the city has also gone through the change from bungalows built over a huge area to high-rise apartment blocks… without a drainage city master plan change.”

Builders should leave gaps between pavements for grass “to allow the water sip under when it rains,” he advises.

In the meantime, Keli can only make sure she has a quick exit strategy ready. She says: “I worry at every drizzle. But this time, I am prepared with a bag packed for any eventuality to rescue my children. As for the shop, there is little I can do. Until the river is cleaned, I still believe this village will flood if the rain keeps coming as they did these two years.”

This article originally appeared on Climate Home News and is shared under Creative Commons license. This article was produced as part of an African reporting fellowship supported by Future Climate for Africa.

Cover photo by Sophie Mbuaga: The Ngong river is choked with garbage as it passes through Hazina village.
Global water supply shrinks in rainier world

Global water supply shrinks in rainier world

By Tim Radford

The global water supply is dwindling, even though rainfall is heavier. Once again, climate change is to blame.

Even in a world with more intense rain, communities could begin to run short of water. New research has confirmed that, in a warming world, extremes of drought have begun to diminish the world’s groundwater – and ever more intense rainstorms will do little to make up the loss in the global water supply.

And a second, separate study delivers support for this seeming paradox: worldwide, there is evidence that rainfall patterns are, increasingly, being disturbed. The number of record-dry months has increased overall. And so has the number of record-breaking rainy months.

Both studies match predictions in a world of climate change driven by ever-higher ratios of greenhouse gases in the atmosphere, from ever-increasing combustion of fossil fuels. But, unlike many climate studies, neither of these is based on computer simulation of predicted change.

Each is instead based on the meticulous analysis of huge quantities of on-the-ground data. Together they provide substance to a 40-year-old prediction of climate change research: that in a warming world, those regions already wet will get ever more rain, while the drylands will tend to become increasingly more arid.

As global temperatures creep up – and they have already risen by 1°C in the past century, and could be set to reach 3°C by 2100 – so does the capacity of the atmosphere to absorb more moisture. It follows that more rain must fall. But at the same time more groundwater evaporates, and the risk of damaging drought increases.

“What we did not expect, despite all the extra rain everywhere in the world, is that the large rivers are drying out”

Australian scientists report in the journal Water Resources Research that they studied readings from 43,000 rainfall stations and 5,300 river monitoring sites in 160 countries. And they confirm that even in a world of more intense rain, drought could become the new normal in those regions already at risk.

“This is something that has been missed. We expected rainfall to increase, since warmer air stores more moisture – and that is what climate models predicted too,” said Ashish Sharma, an environmental engineer at the University of New South Wales.

“What we did not expect, despite all the extra rain everywhere in the world, is that the large rivers are drying out. We believe the cause is the drying of soils in our catchments. Where once these were moist before a storm event – allowing excess rainfall to run off into rivers – they are now drier and soak up more rain, so less water makes it as flow.”

The study matches predictions. Just in the last few months, climate scientists have warned that catastrophic climate change could be on the way, and that the double hazard of heat waves and sustained drought could devastate harvests in more than one climatic zone in the same season; and that those landlocked rainfall catchment areas that are already dry are becoming increasingly more parched.

But over the same few months, researchers have established repeatedly that tomorrow’s storms will be worse and that more devastating flash floods can be expected even in one of the world’s driest continents, Australia itself.

Less water available

Of all rainfall, only 36% gets into aquifers, streams and lakes. The remaining two thirds seeps into the soils, grasslands and woodlands. But more soil evaporation means less water is available from river supplies for cities and farms.

US researchers have already confirmed that if soils are moist before a storm, 62% of rainfall leads to floods that fill catchments. If soils are dry, only 13% of the rain leads to flooding.

“It’s a double whammy. Less water is ending up where we can’t store it for later use. At the same time, more rain is overwhelming drainage infrastructure in towns and cities, leading to more urban flooding,” said Professor Sharma.

“Small floods are very important for water supply, because they refill dams and form the basis of our water supply. But they’re happening less often, because the soils are sucking up extra rain. Even when a major storm dumps a lot of rain, the soils are so dry they absorb more water than before, and less reaches the rivers and reservoirs”, he said. “We need to adapt to this emerging reality.”

In the second close look at change so far, researchers based in Germany report in the journal Geophysical Research Letters  that they analysed data from 50,000 weather stations worldwide to measure rainfall on a monthly basis.

Climate drives aridity

The US has seen a more than 25% increase of record wet months in the eastern and central regions between 1980 and 2013. Argentina has seen a 32% increase. In central and northern Europe the increase is between 19% and 37%; in Asian Russia, it has been about 20%.

But in Africa south of the Sahara the incidence of very dry months has increased by 50%. “This implies that approximately one out of three record dry months in this region would not have occurred without long-term climate change,” said Dim Coumou, of the Potsdam Institute for Climate Impact Research.

“Generally, land regions in the tropics and sub-tropics have seen more dry records, and the northern mid- to high-latitudes more wet records. This largely fits the patterns that scientists expect from human-caused climate change.”

His colleague and lead author Jascha Lehmann said: “Normally, record weather events occur by chance and we know how many would happen in a climate without warning. It’s like throwing a dice: on average one out of six times you get a six.

“But by injecting huge amounts of greenhouse gases into the atmosphere, humankind has loaded the dice. In many regions, we throw sixes much more often, with severe impacts for society and the environment.

“It is worrying that we see significant increases of such extremes with just one degree of global warming.”

This article was originally published on Climate News Network.

Cover photo by Oxfam/Flickr (CC-BY 2.0): Water shortage in Ethiopia.