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The retreat of the planet's glaciers is one of the most visible and dramatic indicators of the far-reaching impact of climate change on the world's ecosystems.

Now, a new paper in Nature Reviews Biodiversity has shed further light on how glacial retreat drives unmitigated changes to ice, water, and land—and how their loss threatens the health of our planet.

The research review analyzed more than 160 research papers focused on specific aspects of glacial retreat to reveal the big picture: global impact on biodiversity and ecosystem function showing that thousands of species that have evolved to live in these unique ecosystems are threatened by the rapid melting of glaciers.

Scientists from around the world, including Securing Antarctica's Environmental Future (SAEF) researchers from the University of Wollongong (UOW), the British Antarctic Survey, Cambridge University and the University of Otago, as well as from the University of Lausanne, University of Minnesota, University of Milan contributed to the paper.

Contributing author Distinguished Professor Sharon Robinson AM, an ARC Laureate Fellow in UOW's School of Science, said glaciers contain ice that can be thousands of years old, providing a vital snapshot of how the history and health of Earth has evolved over time.

"Glaciers are one of the most valuable tools we have for understanding the health of our planet, particularly in the face of a warming climate," said Professor Robinson, Deputy Director of Science Implementation at SAEF. "Glaciers and glacially influenced ecosystems host unique biodiversity spanning all kingdoms of life, but glaciers are retreating as the global climate warms, threatening specialist species, ecosystem functions and stability.

"Glacier retreat drives changes in biodiversity and ecosystem functions across countless different habitats, from the surfaces of glaciers to newly exposed terrestrial and marine ecosystems. Glacial ecosystems worldwide contain thousands of microorganisms, plants, invertebrates and vertebrates."

Due to a warming climate, glaciers are retreating at a faster rate than at any other point in history, and worldwide, they are predicted to lose a third of their mass by 2050.

Glaciers are formed on land and when they melt, slowly, the water runoff flows into rivers and streams. However, when glaciers melt rapidly, the immense water runoff stresses local ecosystems, reduces water security for people, flora and fauna, and contributes to rising sea levels.

Retreating glaciers can change ocean currents and have been linked to destructive global weather patterns and the collapse of fisheries around the world.

On a micro level, Professor Robinson said the disappearance of glaciers sparked a cascade of effects on the species and nutrients that call these critical ecosystems home. While glacier-free landscapes initially provide space for pioneer species (species that are the first to colonize a new environment) to thrive, the change in ecosystem eventually leads to a loss of biodiversity.

"The unique ecosystem that characterizes glaciers, the intricate combination of biodiversity and microorganisms that thrive in this place, gives way over time, as generalist species—species that can thrive in many different places, but are not unique to that environment—take over," she said.

"For example, given that three quarters of Earth's freshwater is stored in glaciers, rapid retreat will lead to the disappearance or considerable disruption of many aquatic ecosystems and species. This includes food supply, foraging areas and mating grounds and could lead to local extinctions.

"The future of mammals who use glaciers as refuges or as places to nest is also uncertain. Essentially, the distinctive functions performed by glaciers may be eroded, leading to long-time impacts on the planet's delicate ecosystem."

Professor Robinson said the review highlighted the need for a better understanding of the evolution of ecosystems and the complex interplay of species following glacier retreat, which would help to predict the consequences for biodiversity and develop precise conservation strategies.

"We need to understand the impacts to be able to inform management conservation practices and policies, which could mitigate the devastating changes taking place in the glacial landscape," she observed.

The United Nations has declared 2025 as the International Year of Glaciers' Preservation—an opportunity to raise global awareness about the critical role of glaciers in the climate system and the hydrological cycle, and the economic, social and environmental impacts of these impending changes.