February 19, 2025

expert reaction to study of glacier melt this century

A study published in Nature estimates global glacier melting from 2000 to 2023. 

Dr Alex Brisbourne, who is a Glacier Geophysicist at British Antarctic Survey, said:

“Although the results broadly agree with what has been published previously, this study is pinning down a lot of the details of glacier change that we haven’t previously been able to identify. Although not of immediate significant impact, this will give us more confidence in projections of the future contributions of glaciers to sea level rise. It also improves our understanding of local variations. One result that stands out is that we are on a pathway to higher glacier mass loss than the previous lowest (most optimistic) estimates.

“2cm over 20 years doesn’t sound like much but the study shows that the rate of glacier melt is increasing and so is the contribution to sea level rise. And remember, this on top of other factors like thermal expansion of the ocean and ice loss from Greenland and Antarctica. If you add all these together and include local effects, that‘s when we start to see immediate impact, especially during storm surges for example. All these contributions are increasing as a result of greenhouse gas emissions and global warming. Any reduction in emissions will help reduce the impact of sea level rise over the next few decades. Every fraction of a degree of warming that we can prevent will reduce this impact.

“Mountain glaciers contain some of the largest freshwater reservoirs on Earth. Meltwater released in the summer provides the water supply to a billion people and sustains an enormous amount of industry and agriculture. This study confirms that if we don’t curb greenhouse gas emissions, around half of the global glacier mass will be lost by 2100. The impact of this will be felt way beyond those immediately downstream of the glaciers.”

Prof Andrew Shepherd, Head of Department of Geography and Environmental Science, Northumbria University, said:

“This is really important as it’s an authoritative assessment from the community working on this topic. It confirms that the pace of glacier melting is accelerating over time. Glacier melting has two main impacts; it causes sea level rise and it disrupts the water supply in rivers that are fed by meltwater. Around 2 billion people depend on meltwater from glaciers and so their retreat is a big problem for society – it’s not just that we are losing them from our landscape, they are an important part of our daily lives.

“Even small amounts of sea level rise matter because it leads to more frequent coastal flooding. Every centimetre of sea level rise exposes another 2 million people to annual flooding somewhere on our planet.

“Community assessments like GLAMBIE are vital as they give people confidence to make use of their findings. That includes other climate scientists, governments, and industry, plus of course anyone who is concerned about the impacts of global warming. Around 2 billion people depend on meltwater from glaciers and so their retreat is a big problem for society – it’s not just that we are losing them from our landscape, they are an important part of our daily lives.”

Prof Martin Siegert, Professor of Geosciences and Deputy VC at the University of Exeter, said:

“Two centimetres might not sound a lot, but this is the contribution from small glaciers – not the whole of the ice on the planet, and not from Greenland and Antarctica. Sea level has risen by 20cm since 1850; 50% from the sea being warmer and expanding, 50% (10cm) due to glacier melt. However, ice sheets are now losing mass at increasing rates (6x more than 30 years ago), and when they change, we stop talking centimetres and start talking metres. For example, the last ice age was 20,000 years ago, and between then and 10,000 years ago as we warmed out of the ice age, sea level rose by 130m, due primarily to collapse of ice sheets.

“This research is concerning to us, because it predicts further glacier loss, which can be considered like a ‘canary in the coal mine’ for ice sheet reaction to global warming and far more sea level rise this century and beyond. The IPCC indicates 0.5-1m this century – but that is with a 66% certainty – hence 1/3 chance it could be higher under ‘strong’ warming, which unfortunately is the pathway we are on presently.”

‘Community estimate of global glacier mass changes from 2000 to 2023’ by The GlaMBIE Team was published in Nature at 16:15 UK time on Wednesday 19^th February. 

Declared interests

Dr Alex Brisbourne: No interests to declare

Prof Andrew Shepherd: No conflicts to declare

Prof Martin Siegert: No COI