Record-Breaking Glacier Meltdown Shocks Scientists Globally

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Aletsch Glacier is more than 20 kilometers long and stands as the largest in the European Alps. However, its front has receded by around 3.2 kilometers since 1900, with over one kilometer lost in just the last two decades alone.

The most comprehensive scientific analysis to date reveals that glaciers worldwide are melting faster than ever recorded due to climate change. These frozen rivers of ice serve as crucial freshwater resources for millions and hold enough water to raise global sea levels by 32 centimeters if they were entirely melted.

Since the turn of the century, these glaciers have lost more than 6,500 billion tonnes of ice—equivalent to five percent of their total mass. The pace at which they are melting is also accelerating; over the past decade, losses were almost a third higher compared to the period between 2001 and 2011.

The study compiled more than 230 regional estimates from research teams across the globe, enhancing scientists’ confidence about the current rate of glacier melt and their future trajectory. Glaciers are excellent indicators of climate change; in a stable environment, they maintain roughly constant size by gaining ice through snowfall and losing it through melting.

However, glaciers have been shrinking almost universally over the past two decades as temperatures rise due to human activities like burning fossil fuels. From 2000 to 2023, glaciers outside major ice sheets in Greenland and Antarctica lost an average of around 270 billion tonnes of ice annually.

These numbers can be hard to comprehend. Michael Zemp, the director of the World Glacier Monitoring Service and lead author of the study, compares it by saying that losing 270 billion tonnes corresponds to supplying water for all humans on Earth for 30 years if they consume three liters per person daily.

The rate of change has been particularly dramatic in some regions. Central Europe experienced a loss of about 39% of its glacier ice within little over two decades.

The key novelty of this study, published in the journal Nature, lies not only in confirming that glaciers are melting faster but also in consolidating data from various research teams across the globe. Scientists use different methods like field measurements and satellite data to estimate changes; each has its strengths and weaknesses. Direct glacier studies offer detailed information but cover a small fraction of over 200,000 global glaciers.

Combining these approaches gives scientists greater certainty about ongoing conditions, which is vital for stakeholders including other climate scientists, governments, industries, and concerned citizens to act with confidence on the findings.

Glaciers take time to fully respond to a changing climate—between a few years and many decades depending on their size. Therefore, continued melting is expected in coming years. Crucially, the amount of ice lost by the end of this century will largely depend on how much humanity continues to warm Earth through greenhouse gas emissions.

Avoiding warming could mean losing only a quarter of global glacier ice instead of nearly half if uncontrolled climate change persists, according to the study’s warnings. “Every tenth of a degree we can avoid in warming saves some glaciers and mitigates significant damage,” explains Prof Zemp.

These consequences extend beyond local landscape changes or ecosystems; they impact water supply for millions reliant on seasonal glacier meltwater as giant reservoirs during drought conditions. When these glaciers vanish, their source of water disappears too.

Globally, even small increases in sea-level from melting glaciers and rising warmer ocean waters can lead to significant coastal flooding frequency. “Every centimeter of sea-level rise exposes another two million people to annual flooding,” Prof Shepherd points out.

Sea levels have already risen over 20 centimeters since 1900, with around half this increase occurring in the early 1990s. Faster increases are anticipated in coming decades due to rising greenhouse gas emissions and warming temperatures.