Glaciers are critical to life – their meltwater is essential for drinking water, agriculture, industry, clean energy production and healthy ecosystems. Rapidly melting glaciers are causing uncertainty to water flows, with profound impacts on people and the planet. Global reductions in carbon emissions and local strategies to adapt to shrinking glaciers are essential. Glacier preservation is hence a core of the plans to tackle climate change and the global water crisis. Glaciers and the water cycle What is the water cycle? The water cycle is like Earth's recycling system! Water moves from the surface to the sky and back again. This journey is made up of four stages : evaporation (water turning into vapour), condensation (water vapour cooling to form clouds), precipitation (rain, snow, or hail falling from the clouds), and collection (water returning to rivers, lakes, oceans, and ‘aquifers’ underground). Every drop you drink today has been part of this infinite journey for billions of years! Fact: The same amount of water exists today as when Earth was formed – over 4.5 billion years ago! Evaporation and condensation The sun is the engine behind the water cycle. It heats water from the soil, oceans, lakes, and rivers, causing it to evaporate. When the water vapour rises high into the air, it cools down and condenses into tiny droplets, forming clouds. Sometimes, clouds gather so much water that they ‘burst’ – causing rain or snow to fall back to Earth. Precipitation and collection: water returns to Earth The clouds can weigh over a million pounds (about 500,000 kilograms). This is because they are made up of countless tiny water droplets. When they become too heavy, they release the water as precipitation. When clouds get heavy, gravity pulls the water back to Earth in the form of precipitation. Depending on the temperature, this can be rain, snow, sleet, or hail. After it falls, the water collects in aquifers, rivers, lakes and oceans, starting the cycle all over again. Nearly 97 per cent of Earth’s water is salty or undrinkable. Only 3 per cent is fresh, and two-thirds of that is frozen in glaciers or otherwise inaccessible. The role of glaciers - Earth's frozen ‘water towers’ Glaciers are giant frozen reservoirs of fresh water. They store about 70 per cent of Earth’s fresh water. During warmer seasons, glaciers slowly melt, releasing water downstream. In many parts of the world, this helps keep water flowing in places that might otherwise dry up. Glaciers are also crucial for regulating Earth’s climate. However, because of climate change, glaciers are melting faster than ever, which could change the water cycle in ways that can affect people and the environment. Though they seem still, glaciers slowly slide downwards across the land, shaping valleys and mountains as they go. Some glaciers can move up to 30 metres a day – about the length of three school buses! Glaciers as climate record-keepers Glaciers are more than just frozen water – they are natural archives of Earth's climate history! Each layer of snow and ice that builds up over time traps small bubbles of air, pollen, dust, and other particles, preserving valuable information about past climates. By studying these layers, scientists can learn about Earth's temperature, atmosphere, and even volcanic eruptions going back thousands of years. Some ice cores from glaciers hold climate records as far back as 800,000 years! These ‘ice time capsules’ help scientists understand the cycles of warming and cooling Earth has gone through. Glaciers and climate change: why we must act now Glaciers are some of the most important sources of fresh water on Earth, but they are melting rapidly due to climate change. As global temperatures rise, glaciers lose mass, contributing to sea level rise and threatening water supplies for billions of people. If we don't act to reduce greenhouse gas emissions, this trend will worsen, leading to more extreme weather, flooding, and water shortages. Glacier facts Glaciers are melting faster than ever. As the planet gets hotter due to climate change, our frozen world is shrinking, making the water cycle more unpredictable and extreme. In 2023, glaciers lost more than 600 gigatons of water, the largest mass loss registered in 50 years. (WMO) About 70% of Earth’s freshwater exists as snow or ice (WMO) Glacial retreat threatens devastation. For billions of people, meltwater flows are changing, causing floods, droughts, landslides and sea level rise, and damaging ecosystems. If all the world's glaciers melted, sea levels could rise by over 60 metres (197 feet), which would drastically change coastlines and flood entire cities! Nearly 2 billion people rely on water from glaciers, snowmelt and mountain run-off for drinking, agriculture, and energy production. (UN Water/UNESCO) Increased glacier melting contributes significantly to global sea-level rise, with today’s sea level about 20 cm higher than in 1900. (IPCC) Limiting global warming to 1.5°C could save glaciers in two-thirds of World Heritage sites. (UNESCO/IUCN) Glacier preservation is a survival strategy. It is mandatory to reduce greenhouse gas emissions and manage meltwater more sustainably for people and the planet. What can we do By limiting global warming to 1.5°C, we can help slow the melting of glaciers and preserve these vital water sources. Adapting to the changing climate is also crucial – this means building better water management systems and preparing communities for changing water availability. Some of the green good deeds are as follows. Save water: Take shorter showers and don’t let the tap run when brushing my teeth, doing dishes and preparing food. Eat local: Buy local, seasonal food and look for products made with less water. Be curious: Find out where my water comes from and how it is shared, and visit a treatment plant to see how my waste is managed. Protect nature: Plant a tree or create a raingarden – use natural solutions to reduce the risk of flooding and store water. Flush safe: Fix leaking water and waste pipes, empty full septic tanks and report dumping of sludge. Build pressure: Write to my elected representatives about budgets for improving water at home and abroad. Stop polluting: Don’t put food waste, oils, medicines and chemicals down my toilet or drains. Clean up: Take part in clean-ups of my local rivers, lakes, wetlands or beaches. Source : UN Water