A new UN report on the state of the world’s water is warning that 5 billion people could be facing water shortages by 2050 as a result of increased demand, pollution and climate change.

The United Nations World Water Development Report, Nature-based Solutions for Water, launched during the 8th World Water Forum currently taking place in Brazil, says that global demand will continue to grow significantly over the foreseeable future.

An estimated 3.6 billion people (nearly half the global population) currently live in areas that are potentially water-scarce at least one month per year - this population could increase to some 4.8–5.7 billion by 2050, according to the report.

The trends in water availability and quality are accompanied by projected changes in flood and drought risks. The number of people at risk from floods is projected to rise from 1.2 billion today to around 1.6 billion in 2050 (nearly 20% of the world’s population). The population currently affected by land degradation/desertification and drought is estimated at 1.8 billion people.

The report says that a focus on 'nature-based solutions' to tackle water supply and quality issues offer a vital means of moving beyond business‐as‐usual to address many of the world’s water challenges.

The fifth in a series of annual, theme-oriented reports, the 2018 edition examines opportunities to harness the natural processes that regulate various elements of the water cycle, which have become collectively known as nature-based solutions (NBS) for water.

NBS use or mimic natural processes to enhance water availability (e.g., soil moisture retention, groundwater recharge), improve water quality (e.g., natural and constructed wetlands, riparian buffer strips), and reduce risks associated with water‐related disasters and climate change (e.g., floodplain restoration, green roofs).

Nature-based solutions to manage water better have a key role in avoiding water related conflicts

Audrey Azoulay, Director-General of UNESCO commented:

“We need new solutions in managing water resources so as to meet emerging challenges to water security caused by population growth and climate change. If we do nothing, some five billion people will be living in areas with poor access to water by 2050. This Report proposes solutions that are based on nature to manage water better. This is a major task all of us need to accomplish together responsibly so as to avoid water related conflicts.”

Upscaling NBS will be central to achieving the 2030 Agenda for Sustainable Development , the report says. NBS show particular promise in achieving progress towards sustainable food production, improved human settlements, access to water supply and sanitation services, and water-related disaster risk reduction. They can also help to respond to the impacts of climate change on water resources.

Almost all investments still channelled to traditional, grey infrastructure projects

However, despite rapidly growing investments in NBS, the evidence suggests that this is still well below 1% of total investment in water resources management infrastructure. The use of nature-based solutions remains marginal and almost all investments are still channelled to traditional, grey infrastructure projects, the report says.

The report suggests there is a historical inertia against NBS due to the continuing overwhelming dominance of grey infrastructure solutions in current institutional arrangements – from public policy to building codes and regulations. The dominance can also exist in civil engineering, market-based economic instruments, the expertise of service providers, and consequentially in the minds of policy makers and the general public.

The report flags up estimates that agricultural production could be increased by about 20% worldwide if greener water management practices were used. One study cited reviewed agricultural development projects in 57 low-income countries and found that using water more efficiently combined with reductions in the use of pesticides and improvements in soil cover, increased average crop yields by 79%.

The vast majority of the growing demand for water will occur in countries with developing or emerging economies.

Green solutions have shown great potential in urban areas

The report also suggests that green solutions have shown great potential in urban areas – for example, New York City has been protecting its three largest watersheds since the late 1990s. Disposing of the largest unfiltered water supply in the USA, the city now saves more than US$ 300 million yearly on water treatment and maintenance costs.

China has also recently initiated a project entitled “Sponge City” to improve water availability in urban settlements and is planning to build 16 pilot Sponge Cities across the country by 2020. The aim is to recycle 70% of rainwater through greater soil permeation, retention and storage, water purification and the restoration of adjacent wetlands.

The report says that increased deployment of NBS is central to meeting key water resources management challenges of sustaining and improving water availability and quality, while reducing water-related risks.

“Without a more rapid uptake of NBS, water security will continue to decline, and probably rapidly so”, the report warns and says NBS “offer a vital means to move beyond business-as-usual.”

Click here to download the report in full