It’s the first ever ‘International Day of the Glacier’ on 21st March 2025. This is part of the ‘International year of glacier preservation‘, being celebrated world-wide.
Why is this being celebrated? Worldwide, glaciers are shrinking. Everywhere we look, glaciers are getting smaller each year; they are melting and losing more ice than they are gaining from snowfall or other solid precipitation.
The loss of glaciers is a loss for society. Glaciers are beautiful in their own right, forming some of our world’s most inspiring landscapes. They have a cultural importance, being revered by mountain and polar communities in different regions across the world. They have an economic importance and value; glaciers bring in funds through tourism and adventure travel. But most importantly, glaciers provide ecosystem services. As they melt, they maintain the river flow down-valley, especially in dry seasons and even more importantly in drought years. This melt eventually makes its way to the sea, where it contributes to global sea level rise.
Global loss of ice
Worldwide, glaciers separate from the large Antarctic and Greenland ice sheets now lose a total of 266 billion tonnes of ice every year, driving 21% of currently observed sea level rise.
In the polar regions lie the World’s enormous two ice sheets: the Greenland Ice Sheet and the Antarctic Ice Sheet. These ice sheets are also melting, raising global sea levels and impacting sea ice and global oceanic circulation.
Rising sea levels
In the UK alone, by the 2080s, over 100,000 properties may be at risk from coastal erosion, and estimates of sea level rise by 2100 are 0.8 to 2.6 m under current climate policies. Currently, in the UK, coastal flooding costs £500 million per year, and costs will rise under sea level rise. Replacing the Thames Barrier and sea defences protecting London, required by 2070 CE, could cost more than £20 billion. These are enormous costs to the UK economy that could be reduced under a cleaner climate that reduces glacier and ice sheet mass loss.
Globally, the rising sea levels would mean that the current 1-in-100 year flood events could occur at least annually in half of tide gauges worldwide. With global coastal populations exceeding 600 million people, many millions of people would be displaced by 2050 CE, leading to increased migration driven by climate change.
Less meltwater in rivers
In mountain regions of the world, communities rely on glacier meltwater. Glacierised basins worldwide cover 26% of the global land surface, and many are densely populated. The mountain ‘water towers’ of the world provide water resources to up to 1.9 billion people worldwide as a result.
This water is used extensively for irrigation, hydropower, industry, and domestic consumption. Mountains are also biodiversity hotspots, with meltwater supporting a range of important and diverse habitats. As the glaciers shrink, water shortages are exacerbated, especially during drought years.
With many millions of people affected, this would increase climate change migration and refugees across numerous international borders.
What does it mean to preserve glaciers?
The most effective way to preserve glaciers is by reducing carbon dioxide emissions and curbing the rise in global heating. While we can hypothesise about potential glacier-geoengineering solutions, none of these are tested and may cause more harm than good. All would require substantial investment in inhospitable and often politically contested parts of the world; funds that would be better invested in clean energy and transport.