SINGAPORE – The warming of the world causes floods, droughts and sea-level rise, while also depleting the available clean water – a source of life.

To adapt to climate change, humanity should change how it manages water resources.

The issue of water has been made a priority on the United Nations COP28 agenda this year, which will be held in Dubai from Nov 30 to Dec 12.

The Straits Times unpacks the reasons behind water scarcity and the links between water and climate.

Q: Where do countries typically get their water from, and what’s the cause of the global water crisis? 

A: Most of the world’s water resources come from surface water, such as lakes, rivers and reservoirs, as well as groundwater – water found beneath the land surface and is accessed through wells, springs and aquifers.

Surface water resources are considered renewable and can be easily replenished through precipitation such as rain or snow.

Groundwater reserves are usually tapped when surface water resources run dry, but they take longer to replenish than surface water.

Groundwater gets replenished when, say, rainfall penetrates the land surface, or with the help of wetlands, which are sometimes located where surface water enters an underground aquifer – porous rock or sediment saturated with groundwater.

Plants growing in the wetlands absorb nutrients like fertiliser and other pollutants, thus helping to filter the water and improve water quality.

However, urbanisation and poor land use planning have made it difficult for water to infiltrate underground. This leads to more surface run-off, which can cause flooding.

Global demand for water has more than doubled since 1960, and is exceeding the natural resources available.

This is a result of growing population and industries such as agriculture – which accounts for 70 per cent of water use yearly – and other sectors like energy production and manufacturing.

But unsustainable water use, the lack of investment in water infrastructure, and weather variability arising from climate change negatively affect available water supply.

An analysis by the World Resources Institute in August found that 25 countries, including India, Iran, Mexico and South Africa, are currently exposed to “extremely high water stress” annually, meaning that they use more than 80 per cent of their renewable water supply for irrigation, livestock, industry and other domestic needs.

So, even a short-term drought can put these places in danger of water shortages.

By 2050, an additional one billion people are expected to live under extremely high water stress, even if the world limits global temperature rise to between 1.3 deg C and 2.4 deg C.

Q: How does climate change exacerbate water scarcity?

A: Climate change is speeding up the water cycle as rising temperatures increase the rate of evaporation. The warmer atmosphere holds more moisture, leading to increased precipitation, such as rain and snow.

However, these effects are not evenly distributed around the world, so some countries experience heavier than normal precipitation, while other countries become more prone to droughts as a result of drier soils.

These climate-related extremes, such as droughts and flooding, are becoming more serious, with a greater proportion of annual precipitation being less spread out during the year, and even happening in one single extreme event.

Frequent droughts can lead to higher frequencies of water stress or water scarcity, while flooding can damage infrastructure and affect the availability of clean water as debris and sedimentation contaminate freshwater systems.

The World Meteorological Organisation (WMO) said in a report in October that the water cycles are “spinning out of balance”, necessitating more robust monitoring systems, particularly in Africa, the Middle East and Asia.

Long-term water supply may also be threatened, as glaciers – which are huge reserves of freshwater for millions of people – are shrinking more rapidly than usual due to rising temperatures.

This also causes flooding and sea-level rise in the longer term. 

Q: Why is water a focus at COP28 in 2023?

A: According to the WMO State of Global Water Resources Report 2022 published in October, too little is known about the true state of the world’s freshwater resources.

“We cannot manage what we do not measure. There must be improved monitoring, data-sharing, cross-border collaboration and assessments of water resources – and an accompanying increase in investments to facilitate this,” said WMO. 

As a result, water issues will be given increased prominence at the upcoming COP28 conference. 

Water is also closely tied to food security, given the heavy reliance of fisheries, crops and livestocks on water, as well as general health.

Lack of access to clean water, such as during heavy flooding, can fuel waterborne diseases like typhoid, malaria and cholera.

Tajikistan and the Netherlands have been appointed by the United Arab Emirates COP presidency to steer negotiations on water at the talks.

Focus areas on the agenda are: 

1. Conserving and restoring freshwater ecosystems

This includes wetlands, mangroves and forests, which have natural water filtration abilities, and can play a crucial role in replenishing groundwater resources.

More than 30 countries will sign the Freshwater Challenge – the ambitious goal of restoring over 300,000km of rivers and 350 million ha of wetlands by 2030.  

2. Enhancing urban water resilience

This entails ensuring that cities have sufficient access to clean water during floods and droughts.

Some examples include ensuring a supply of groundwater, or having standby desalination plants to cope with periods of water scarcity. 

3. Bolstering water-resilient food systems

This includes turning to water-efficient crops, or better managing water use, such as by using sprinklers or drip irrigation rather than flooding fields. 

Plans are also in place to assess countries’ water resilience in their national climate targets and their climate adaptation plans. 

The Urban Water Catalyst Initiative, led by Germany and the Netherlands, will be launched at COP28, to enhance urban water and sanitation utilities in lower- and middle-income countries. 

The initiative will put together a fund to provide financial and technical assistance to seven to 10 utility companies or organisations, which will be unveiled at the conference.