The ancient Chinese philosopher Lao Tzu is quoted as saying, “Nature does not hurry, yet everything is accomplished.” As we race ahead with technological breakthroughs and new approaches to tackle our most pressing problems, it is worth remembering the lessons that can be learned from a teacher that has been amassing knowledge for millennia – this planet.
Nature-based solutions are inspired and supported by natural processes and aim to improve water management. They can involve conserving or rehabilitating natural ecosystems and/or the enhancement or creation of natural processes in modified or artificial ecosystems. Several countries have already benefited greatly from using these approaches for water management.
As this year’s World Water Development Report makes clear, nature-based solutions offer answers to our most pressing water-related challenges and are also directly aligned with both the principles and aims of the 2030 Agenda for Sustainable Development. Business-as-usual approaches to water security are simply no longer viable. Nature-based solutions hold great promise in areas including sustainable food production; improved human settlements; access to drinking water supplies and sanitation; water-related disaster risk reduction; and helping to respond to the impacts of climate change on water resources.
The water-related challenges we face today are immense, and one of the most pressing is the growing demand for this limited resource. From 2017-2050, the world population is expected to increase from 7.7 billion to between 9.4 and 10.2 billion people, with two-thirds of that number living in cities. UNDESA estimates that more than half of this anticipated growth is expected in Africa (1.3 billion) and Asia (.75 billion). Countries with developing or emerging economies will be those most in need of water.
At the same time, the global water cycle is intensifying due to climate change, with wetter regions generally becoming wetter and drier regions drier. An estimated 3.6 billion people (51pc of the global population) now live in areas that could face water scarcity for at least one month per year, and that number could increase to 4.8-5.7 billion by 2050. The International Water Management Institute estimates that total water demand could increase from 680 BCM (billion cubic metres) to 833 BCM by 2025, and to 900 BCM by 2050. The exponential growth of the African population is the main threat for water security in the region in addition to economic and political instability and climate change. Sub-Saharan Africa is currently home to more than 1.2 billion people, and it is estimated that this number will grow by another billion by 2050.
Countries already facing water scarcity challenges may also be forced to cope with the decreased availability of surface water resources in the 2050s. In the 2010s, 1.9 billion people (27pc of the global population) lived in areas of potentially severe water scarcity. About 73pc of those people live in Asia (this is estimated to decrease slightly to 69pc by 2050). African countries are behind the global curve when it comes to providing people with access to clean water. In Sub-Saharan Africa, over 32 percent of people lack access to clean water and water-borne diseases are common. Scientists predict that between 90 million to 220 million people will be exposed to increased water stress due to climate change by the year 2020. This would be devastating for a region that is already prone to water-related issues.
Along with water scarcity, countries are also facing severe crises related to water quality. Since the 1990s, water pollution has worsened in almost all rivers in Africa, Asia and Latin America, according to UNEP. An estimated 80% of all industrial and municipal wastewater is released without any prior treatment, resulting in a growing deterioration of overall water quality with detrimental impacts on human health and ecosystems.
Low- and lower-middle-income countries face the greatest risk of exposure to these pollutants. Countries with growing populations and expanding countries, particularly those in Africa, are more vulnerable to these threats because they lack wastewater management systems.
Given the transboundary nature of most river basins, regional cooperation will be critical to addressing projected water quality challenges.
The effects of environmental pollution on African rivers from the Nile to the Mhlathuze in South Africa are poorly understood. The information on environmental bioaccumulation, bioconcentration and biomagnifications of pollutants on organisms and ecosystems is of little consequence to the average person yet the incidence of environmental health disorders related to waterborne diseases remains high.
Extreme weather events are also taking a terrible toll in human lives and economic losses. Global economic losses from floods and droughts have now surpassed US$40 billion per year across all economic sectors. Storms add another US$46 billion in losses annually. The number of deaths, affected people, and economic losses varies significantly by year and continent, with Africa and Asia being the most affected in all areas. Projected losses due to floods, droughts and storms are estimated to increase to US$200-400 billion by 2030. Such losses strongly affect water, food and energy security and consume most of the current total development aid flow.
Sub-Saharan Africa is predicted to bear the brunt of climate change’s negative effects going forward. Not only will this phenomenon create droughts, floods, famines, and other disasters – unsurprisingly, is it also predicted to severely damage the region’s economic growth.
Nature-based solutions offer effective responses to these challenges. They address overall water scarcity through “supply-side management,” and are recognized as the main solution for achieving sustainable water for agriculture.
Currently, 800 million people are going hungry. By 2050, global food production would need to increase by 50pc to feed the more than nine billion people projected to live on our planet.
Environmentally friendly agricultural systems – ones that use practices such as conservation tillage, crop diversification, legume intensification and biological pest control – perform as well as intensive, high-input systems. The environmental co-benefits of nature-based solutions to increasing sustainable agricultural production are substantial – mediated largely through decreased pressures on land conversion and reduced pollution, erosion and water requirements.
Constructed wetlands for wastewater treatment can also be a cost-effective nature-based solution that provides effluent of adequate quality for several non-potable uses, including irrigation, as well as offering additional benefits including energy production.
Such systems already exist in nearly every region of the world, including the Arab region and Africa (they are relatively common in East Africa). Both natural and constructed wetlands also biodegrade or immobilize a range of emerging pollutants. Recent experiments suggest that for some emerging pollutants, nature-based solutions work better than “grey” solutions and in certain cases may be the only viable option.
Agriculture is perhaps the economic sector that is most affected by the increasing variability of water resources globally, and certainly the most vulnerable in socioeconomic terms due to the dependency of rural communities in developing countries. This sector absorbs, on average, 84pc of the adverse economic impacts of droughts, and 25pc of all damages from climate-related disasters
Nature-based solutions can also help reduce the tremendous estimated investments required to improve water resources infrastructure. It is estimated that approximately US$10 trillion will be required between 2013 and 2030. Watershed management is one nature-based solution that is seen not only as a complement to built or “grey” infrastructure, but one that could also spur local economic development, job creation, biodiversity protection and climate resilience.
Despite the promise of nature-based solutions, the limited data available suggest that investment in green infrastructure remains only a fraction of total investment in water resources management. There are many examples of policies, financing and management interventions where nature-based solutions are absent, even where they are an obvious option.
Nature-based solutions are closely aligned with traditional and local knowledge, including that held by indigenous and tribal peoples, in the context of water variability and change. Indigenous and tribal peoples care for an estimated 22pc of the Earth’s surface and protect nearly 80pc of the remaining biodiversity on the planet, while accounting for nearly 5pc of the world’s population.
Nature-based solutions are crucial to achieving our Sustainable Development Goals, particularly SDG6 (Water), SDG13 (Climate Change), SDG14 (Oceans), SDG2 (Zero hunger) and SDG15 (Ecosystems). Adopting them will, of course, not only improve water management and achieve water security, it will deliver on the tremendous promise of the entire 2030 Agenda for Sustainable Development. Nature-based solutions are not a panacea; however, they will play an essential role in building a better, brighter, safer and more equitable future for all.
(Jayakumar Ramasamy is a Senior Programme Specialist and Regional Hydrologist, UNESCO office in Nairobi)