Questions people ask about glaciers

Glaciers are melting faster than ever, making the water cycle more unpredictable and extreme and putting countless communities and ecosystems at risk.

Preserving the world’s glaciers must be part of the solution in our plans to tackle climate change and the global water crisis.

World Water Day, 22 March 2025, will focus on this critical issue in support of the inaugural World Day for Glaciers, the International Year of Glaciers’ Preservation 2025, and the start of the Decade of Action for Cryospheric Sciences.

As UN-Water gears up for these major events, here are some of the questions people are asking us about glaciers.

?

What is a glacier?

A glacier is a river of ice, often covered in snow, slowly moving down a valley from mountainous areas, with its meltwaters flowing downstream.

Glaciers form when snow piles up over many years, compressing into ice. They move slowly under their own weight, carving landscapes as they go. (Check out The Secret Life of Glaciers infographic and other assets for World Water Day 2025).

Glaciers, along with snow cover, ice sheets, ice shelves, icebergs and all other frozen environments, make up what is known as the cryosphere (based on the Greek word “kryos” for frost or ice cold).

• Covering about 10% of the planet’s surface, ice masses are crucial for sustaining life on Earth. (UNESCO)

??

What is happening to glaciers?

Glaciers are melting faster than ever. In 2023, glaciers lost more than 600 gigatons of water, the largest mass loss registered in 50 years. Iceland has opened a ‘graveyard of glaciers’ commemorating glaciers already lost to global warming.

For billions of people, the increased rate of melting of mountain glaciers creates an alarming set of realities, including floods, droughts, landslides and sea level rise.

• Increased glacier melting contributes significantly to global sea-level rise, with today’s sea level about 20 cm higher than in 1900. (IPCC)

?

Why are glaciers important??

Glaciers provide essential supplies of fresh water for drinking water and sanitation systems, agriculture, industry, clean energy production and healthy ecosystems.

Glaciers also contribute to oceanic circulation, regulating heat, carbon dioxide, and nutrients that sustain food webs across the globe.? By reflecting vast amounts of solar radiation into space, glaciers also help cool the Earth, acting as a natural shield against excessive warming.

• About 70% of Earth’s freshwater exists as snow or ice. (WMO)

“The rooftops of the world are caving in. […] The glaciers are retreating, but we cannot. We must end the fossil fuel age. We must act now to protect people on the frontline.” António Guterres, United Nations Secretary General

??

How can glaciers be saved?

Saving the world’s glaciers is a survival strategy.

The World Water Day 2025 campaign is calling for further, drastic reductions of greenhouse gas emissions and for the sustainable management of meltwater.

The United Nations has outlined five strategies for mitigating and adapting to the impacts of climate change on glaciers:

1. Reducing global emissions to limit global warming to 1.5°C above pre-industrial levels (The Paris Agreement) is essential to slow the melting of glaciers and reduce rising sea levels, fresh water shortages, floods and landslides.[i]
2. Strengthening water resource management to cope with excessive flooding and drought. In many areas there is a need to store seasonal glacial meltwater, improve their water efficiency and safely reuse wastewater.
3. Helping vulnerable communities adapt, including by building more resilient agricultural systems, and improving early warning and disaster response systems.
4. Restoring ecosystems around glaciers to stabilize water flows, maintain biodiversity, and support the adaptation of local communities to changing water patterns, including tackling land degradation.
5. Countries cooperating internationally by sharing knowledge, data, and strategies for water conservation to manage the impact of glacier melt on a regional scale.

??

Do something to help save our glaciers.

Support the World Water Day 2025 campaign on ‘Glacier Preservation’ at www.worldwaterday.org from now until 22 March 2025.

Learn more in the Fact Sheet and Activation Kit for younger people and schools.

Use the campaign assets to promote the issues on your channels.

Get The Secret Life of Glaciers infographic.

[i] In January 2025, the World Meteorological Organization (WMO) confirmed 2024 as the warmest year on record at about 1.55°C above pre-industrial level.

“A single year of more than 1.5°C for a year does NOT mean that we have failed to meet Paris Agreement long-term temperature goals, which are measured over decades rather than an individual year.” Celeste Saulo, WMO Secretary-General.