![Freshwater lake surrounded by trees](/sites/default/files/styles/full_width/public/2026-07/Freshwater%20event%20page.jpg?itok=yWlEytPq)

[David Hoefler](https://unsplash.com/photos/green-trees-near-body-of-water-during-daytime-NpMl97aTmco)/Unsplash



 

 

## [Freshwater](/freshwater)

## A closer look at the freshwater system



The global hydrologic cycle — the movement and storage of water through the atmosphere and across ecosystems — sustains life on Earth. Yet human activity is increasingly disrupting this cycle, threatening ecosystems, economies and people’s well-being around the world.

### Freshwater underpins life on Earth 

As water moves through freshwater ecosystems, some is extracted by people as a water resource, providing drinking water, sanitation and hygiene, supporting agricultural production, generating energy and underpinning livelihoods. Access to freshwater is a cornerstone of [sustainable social and economic development](https://globalgoals.org/goals/6-clean-water-and-sanitation/).

At the same time, although freshwater ecosystems such as wetlands like peatlands and mangroves, rivers and lakes cover less than 1% of the Earth’s surface, they support [extraordinary biodiversity](https://academic.oup.com/bioscience/article/70/4/330/5732594), harboring nearly 10% of all known species. These ecosystems also deliver critical services, including water purification, nutrient cycling, and enormous carbon storage benefits.

For example, wetlands alone store an estimated [20-25% of the world’s soil carbon](https://archive.ipcc.ch/ipccreports/sres/land_use/index.php?idp=196), and some freshwater ecosystems like [mangroves and peatlands](https://doi.org/10.1126/science.abn1479) rank among the most carbon-dense globally, holding at least [three times more carbon per hectare](https://www.nature.com/articles/s41558-020-0738-8) than boreal, temperate and tropical forests. Healthy freshwater ecosystems can also boost resilience to climate impacts, from [providing flood protection](https://www.sciencedirect.com/science/article/pii/S2590332222002135) to [reducing the impacts of wildfires](https://link.springer.com/article/10.1007/s13157-025-02005-8).

### Human-driven pressures on the water cycle, freshwater ecosystems and water resources are accelerating, driving devastating impacts  

Yet, the world is [in the midst](https://unu.edu/inweh/collection/global-water-bankruptcy) of a water crisis in many regions as the hydrologic cycle is thrown [increasingly out of balance](https://watercommission.org/#report) because of human activity. Climate change — driven by emissions across the world’s [power](https://systemschangelab.org/power), [buildings](https://systemschangelab.org/buildings), [industry](https://systemschangelab.org/industry), [transport](https://systemschangelab.org/transport), forests and land and [food and agriculture](https://systemschangelab.org/food-and-agriculture) sectors — is [altering precipitation and evaporation patterns](https://www.ipcc.ch/report/sixth-assessment-report-working-group-i/), increasing the frequency and severity of droughts and floods.

At the same time, land-use change, pollution, overextraction of water, overexploitation of freshwater species, and the accelerating spread of invasive, alien species are degrading freshwater ecosystems at an [alarming rate](https://pmc.ncbi.nlm.nih.gov/articles/PMC7138689/), worsening the climate and biodiversity crises.

Because both inland and coastal freshwater ecosystems play a [central regulating role in the hydrologic cycle](https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter08.pdf) — governing the storage, flow and quality of water as it moves through landscapes — their degradation destabilizes the cycle itself. These pressures often [compound](https://online.ucpress.edu/elementa/article/doi/10.1525/elementa.256/112455/Meeting-the-challenge-of-interacting-threats-in) one another. For example, rising temperatures driven by climate change [can concentrate pollutants and increase their toxicity](https://wires.onlinelibrary.wiley.com/doi/full/10.1002/wat2.1724), amplifying risks to freshwater species and ecosystems.

![chart visualization](https://public.flourish.studio/visualisation/29868727/thumbnail)

The consequences are severe. Since 1970, nearly [a third of assessed freshwater ecosystems](https://pmc.ncbi.nlm.nih.gov/articles/PMC7138689/) have disappeared, including [more than 400 million hectares of wetlands](https://www.global-wetland-outlook.ramsar.org/outlook) — an area nearly the size of India. Freshwater species are declining faster than those in [marine or terrestrial habitats](https://www.ipbes.net/global-assessment), with [one-fifth](https://www.iucnredlist.org/search/stats) of assessed species now [threatened with extinction](https://academic.oup.com/bioscience/article/70/4/330/5732594). As ecosystems that store vast amounts of carbon are disturbed, greenhouse gas emissions are also increasing. [One estimate suggests](https://www.unep.org/news-and-stories/press-release/peatlands-degrading-177-countries-putting-climate-goals-risk) degraded peatlands alone are responsible for 4% of global human-driven emissions.

These disruptions are already reverberating through [human systems](https://wires.onlinelibrary.wiley.com/doi/10.1002/wat2.1633), increasingly threatening [lives and livelihoods](https://www.unwater.org/publications/un-world-water-development-report-2024). [Growing water stress and scarcity](https://www.sciencedirect.com/science/article/pii/S0048969721033015?casa_token=Kz3ugaIs668AAAAA:ybtDo8GgTc_Se7KjZUMYTI5bs_QSBcQNB1Vri5SXk6MexYynVTNrZIilr1HE5vYc2QAfUTM_Iw) constrain access to water for domestic use, agriculture and energy systems, while [more frequent and severe floods cost lives, displace communities and damage infrastructure](https://www.nature.com/articles/s41467-022-30727-4). [Pollution also degrades water quality](https://onlinelibrary.wiley.com/doi/full/10.1111/brv.12480?casa_token=pBTX6Nk7oJYAAAAA%3AYQ5LJV79Q0B0L4c324SLGaEaXY_Q3qSVrser9fFCdo5zrT-hjrhdYG8JduhzrlLmMZ3AOCe5ieK4CSW7), threatening [human health](https://www.unep.org/interactives/wwqa/technical-highlights/health-and-water-quality), and [billions of people](https://www.who.int/publications/i/item/9789240115149) still lack access to safely managed drinking water, sanitation and hygiene services.

 ![Three freshwater figures that are well off track](/sites/default/files/2026-08/Water%2C%20sanitation%20and%20hygiene-16x9.png)

 

### A unified, accelerated effort can help reverse these trends  

Immediate, widespread action across the global freshwater system is needed to address the world’s intertwined climate and biodiversity crises while achieving [Sustainable Development Goal 6](https://globalgoals.org/goals/6-clean-water-and-sanitation/): ensuring availability and sustainable management of water and sanitation for all by 2030.

This will mean [effectively halting degradation and conversion of freshwater ecosystems](https://systemschangelab.org/freshwater/freshwater-ecosystems-conversion-and-degradation) — particularly intact, carbon-rich peatlands, mangroves and salt marshes — and [restoring those degraded](https://systemschangelab.org/freshwater/ecosystem-restoration) by human activities. These actions will be essential to safeguard the services these ecosystems provide and to [minimize disruptions to the quantity and timing of the water cycle](https://systemschangelab.org/freshwater/water-cycle).

Alongside these changes, the world must tackle the primary, direct drivers of freshwater biodiversity loss, including by [sharply reducing water pollution and improving water quality](https://systemschangelab.org/freshwater/water-pollution-water-quality), [preventing overfishing and overexploitation of freshwater species](https://systemschangelab.org/freshwater/protect-freshwater-species?indicatorId=7651), and slowing the spread of invasive alien freshwater species. Throughout, the world must also [ensure equitable and affordable access to safe drinking water, sanitation and hygiene for all](https://systemschangelab.org/freshwater/clean-water-access). Access to these services is not only a [basic human right](https://news.un.org/en/story/2010/07/346122) but the very foundation of [human dignity and global prosperity](https://www.unwater.org/water-facts/human-rights-water-and-sanitation?utm_source=chatgpt.com).

 ![Figure of the seven freshwater shifts](/sites/default/files/2026-08/Critical%20shifts%20in%20freshwater_F2-16x9.png)

 

Several cross-cutting enablers are essential to achieving progress across all shifts. Strengthening transboundary governance will be critical: [Over 60% of the world’s freshwater flows are shared across nations](https://blogs.worldbank.org/en/water/water-knows-no-borders-transboundary-cooperation-key-water-security-and-avoiding-conflict), making coordinated international action indispensable. Securing the land and water rights of Indigenous Peoples, Afro-descendant Peoples, and local communities — who are often frontline stewards of freshwater ecosystems — is equally essential alongside expanding financing and policy support, improving institutional capacity and enforcing environmental laws and regulations.

Transforming the global freshwater system will also require coordinated action on [food](https://systemschangelab.org/food-and-agriculture), forests and land, [industry](https://systemschangelab.org/industry) and [cities](https://systemschangelab.org/cities) — systems that drive pressures on water resources, ecosystems and the water cycle that connects them.

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*The shift on invasive alien freshwater species is not yet available online, as the underlying research is still underway. It represents a critical part of the work and will be published later this year.*



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