More than half of humanity will face some form of water stress by 2050 due to the effects of climate change on the global water cycle, the United Nations said on World Water Day, March 22. Reducing the impacts and drivers of climate change will require major shifts in the way we use and reuse the Earth’s limited water resources.
“Climate change will affect the availability, quality and quantity of water for basic human needs,” the World Water Development Report 2020 said, and “potentially billions of people” will suffer. More efficient use of water in daily life, agriculture and industry is needed to contain global emissions, said this year’s report that focuses on water and climate change.
“The word ‘water’ rarely appears in international climate agreements, even though it plays a key role in issues such as food security, energy production, economic development and poverty reduction.”Audrey Azoulay
“Water is the primary medium through which we perceive the effects of climate disruption, from extreme weather events, such as droughts and floods, to glacial melting, saltwater intrusion and sea level rise,” UN Secretary-General António Guterres said in a message. “Global heating and unsustainable use will create unprecedented competition for water resources, leading to the displacement of millions of people. This will negatively affect health and productivity and act as a threat multiplier for instability and conflict.”
Global water use has increased six-fold over the past 100 years and continues to grow steadily at a rate of about 1% per year, the report said. Globally, the rate of groundwater depletion has doubled between 1960 and 2000. Without good management strategies, this will entail huge risks to life, said the report compiled by Unesco in collaboration with UN Water.
“The word ‘water’ rarely appears in international climate agreements, even though it plays a key role in issues such as food security, energy production, economic development and poverty reduction,” Unesco Director-General Audrey Azoulay said in a statement.
Impacts of climate on tropics and glaciers
Much of the impacts of water and climate change will be felt in the tropical zones and in the higher reaches where the glaciers are. Changes in precipitation and temperature will directly affect the terrestrial water budget. “Accelerated melting of glaciers is expected to have a negative effect on the water resources of mountain regions and their adjacent lowlands, with tropical mountain regions being among the most vulnerable,” the report said.
In South Asia, earlier snowmelt and the loss of glacial buffering in the Hindu Kush Himalayas will affect the seasonal water supply for a significant proportion of the population of the subcontinent and change the frequency and severity of extremes. By 2050, 40% of the world’s population is projected to live under severe water stress, including almost the entire population of the Middle East and South Asia, and significant parts of China and North Africa.
The report said that South Asia is highly vulnerable to climate-induced disasters and extreme weather events, which are disproportionately burdening poor and vulnerable groups. In August 2017 alone, intense monsoon rains affected 40 million people in Bangladesh, India and Nepal, claiming nearly 1,300 lives and putting 1.1 million people in relief camps.
Floods could cost South Asia as much as USD 215 billion each year by 2030, the report said. “Floods are also expected to contaminate water sources, destroy water points and sanitation facilities, and therefore pose a challenge to universal access to sustainable water and sanitation services.”
Climate change and groundwater resources
Climate change and increasing demand for water will also put stress on groundwater resources as the availability of surface water is affected by increasing climate variability. Groundwater use could increase by 30% by 2050. The increase in demand for irrigation has already led to severe groundwater stress in some areas, especially in two of Asia’s major food baskets – the North China Plain and Northwest India.
Overuse of groundwater also leads to concentrations of pollutants such as arsenic, iron, manganese and fluoride, a serious concern where groundwater quality is already low, such as in certain locations in India and Bangladesh, North and Latin America, and Africa, the report said.
The report urged regional cooperation on governance, investment and information in regards to Asia’s transboundary basins. These basins face enormous challenges resulting from development, including urbanisation, hydropower and pollution, and from climate change.
Bangladesh, for example, comprises the largest delta in the world. It lies at the confluence of three major rivers draining Bhutan, China, India and Nepal, but has only 7% of the catchment area of these basins. However, a water-sharing agreement is in place for only one of its 57 transboundary rivers – the Ganga.
Use of water in agriculture has increased manifold in recent decades, the report said. Emerging solar pumping technologies in farm production can play an important role in mitigating greenhouse gas emissions. In India, from around 18,000 in 2014–2015, solar-based irrigation projects (SIPs) have increased to nearly 200,000 in recent years, an annual growth rate of 68%. The Indian government has incorporated the model in its USD 21 billion KUSUM scheme, which aims at installing two million SIPs.
“We must urgently scale up investments in healthy watersheds and water infrastructure, with dramatic improvements in the efficiency of water use,” Guterres said. “And, above all, we must use this year and COP26 in Glasgow to bend the emissions curve and create a secure foundation for water sustainability.”
The annual UN climate summit in Glasgow in November this year is the most important since the 2015 Paris Agreement, when pledges that countries made will be reviewed for the first time. It is also expected that the Glasgow summit will lay down a roadmap for the future.
“Although water is not mentioned in the Paris Agreement per se, it is an essential component of nearly all the mitigation and adaptation strategies,” the report said.