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Water and Climate Change

Climate change is primarily a water crisis. We feel its impacts through worsening floods, rising sea levels, shrinking ice fields, wildfires and droughts.

However, water can fight climate change. Sustainable water management is central to building the resilience of societies and ecosystems and to reducing carbon emissions. Everyone has a role to play – actions at the individual and household levels are vital.

The issue explained

Water and climate change are inextricably linked. Extreme weather events are making water more scarce, more unpredictable, more polluted or all three. These impacts throughout the water cycle threaten sustainable development, biodiversity, and people’s access to water and sanitation. 

Flooding and rising sea levels can contaminate land and water resources with saltwater or faecal matter, and cause damage to water and sanitation infrastructure, such as waterpoints, wells, toilets and wastewater treatment facilities. 

Glaciers, ice caps and snow fields are rapidly disappearing. Meltwater feeds many of the great river systems. Volatility in the cryosphere can affect the regulation of freshwater resources for vast numbers of people in lowland areas.

Droughts and wildfires are destabilizing communities and triggering civil unrest and migration in many areas. Destruction of vegetation and tree cover exacerbates soil erosion and reduces groundwater recharge, increasing water scarcity and food insecurity.

Growing demand for water increases the need for energy-intensive water pumping, transportation, and treatment, and has contributed to the degradation of critical water-dependent carbon sinks such as peatlands. Water-intensive agriculture for food production, particularly meat, and for growing crops used as biofuels, can further exacerbate water scarcity.

The way forward

Climate policymakers must put water at the heart of action plans. Sustainable water management helps society adapt to climate change by building resilience, protecting health and saving lives. It also mitigates climate change itself by protecting ecosystems and reducing carbon emissions from water and sanitation transportation and treatment.

Politicians must cooperate across national borders to balance the water needs of communities, industry, agriculture and ecosystems.

Innovative financing for water resource management will be needed to help attract investment, create jobs, and support governments in fulfilling their water and climate goals.

Sustainable, affordable and scalable water solutions include:

  • Improving carbon storage. Peatlands store at least twice as much carbon as all of Earth’s forests. Mangrove soils can sequester up to three or four times more carbon than terrestrial soils. Protecting and expanding these types of environments can have a major impact on climate change.
  • Protecting natural buffers. Coastal mangroves and wetlands are effective and inexpensive natural barriers to flooding, extreme weather events and erosion, as the vegetation helps regulate water flow and binds the soil in flood plains, river banks and coastlines.
  • Harvesting rainwater. Rainwater capture is particularly useful in regions with uneven rainfall distribution to build resilience to shocks and ensure supplies for dry periods. Techniques include rooftop capture for small-scale use and surface dams to slow run-off to reduce soil erosion and increase aquifer recharge.
  • Adopting climate-smart agriculture. Using conservation techniques to improve organic matter to increase soil moisture retention; drip irrigation; reducing post-harvest losses and food waste; and, transforming waste into a source of nutrients or biofuels/biogas.
  • Reusing wastewater. Unconventional water resources, such as regulated treated wastewater, can be used for irrigation and industrial and municipal purposes. Safely managed wastewater is an affordable and sustainable source of water, energy, nutrients and other recoverable materials.
  • Harnessing groundwater. In many places, groundwater is over-used and polluted; in other places, it is an unknown quantity. Exploring, protecting and sustainably using groundwater is central to adapting to climate change and meeting the needs of a growing population.

Facts and Figures

  • Only 0.5% of water on Earth is useable and available freshwater – and climate change is dangerously affecting that supply. Over the past 20 years, terrestrial water storage – including soil moisture, snow and ice – has dropped at a rate of 1 cm per year, with major ramifications for water security. (WMO, 2021)
  • By 2050, the number of people at risk of floods will increase from its current level of 1.2 billion to 1.6 billion. In the early to mid-2010s, 1.9 billion people, or 27% of the global population, lived in potential severely water-scarce areas. In 2050, this number will increase to 2.7 to 3.2 billion people. (United Nations, 2020)
  • Over a fifth of the world’s basins have recently experienced either rapid increases in their surface water area indicative of flooding, a growth in reservoirs and newly inundated land; or rapid declines in surface water area indicating drying up of lakes, reservoirs, wetlands, floodplains and seasonal water bodies. (UN-Water, 2021)
  • The ambition of new climate change mitigation pledges for 2030 need to be four times higher to limit global warming to 2°C and seven times higher to get on track to limit global warming to 1.5°C. (UNEP, 2021
  • The current Arctic sea-ice cover (both annual and late summer) is at its lowest level since at least 1850 and is projected to reach practically ice-free conditions at its summer minimum at least once before 2050. (IPCC, 2021