MOUNTAIN GLACIERS The retreat of mountain glaciers provides some of the clearest evidence of global warming. Of course, in order to attribute the cause to global warming, scientists need to distinguish trends with and without the increase in temperature. This is called distinguishing the “signal” from the “noise”. While scientists use more precise data than just the visual appearance of glaciers, photographs showing the dramatics retreat of glaciers are striking.
The National Snow and Ice Data Center has a special collection of glaciers in the US that have been rephotographed over the years. See examples from this collection below and explore more here and in the film Chasing Ice linked below.
Compare the McCall glacier in the Arctic National Wildlife Refuge of Alaska in 1958 and then again in 2003. Find more in-depth research on this particular glacier here.
Photographer and film maker, James Balog, documents rapidly melting glaciers around the world in the Emmy-award winning film, Chasing Ice. See the trailer below and find more information on their website.
The melting of mountain glaciers has severe consequences beyond rising sea levels. Many mountain glacial systems feed rivers that provide drinking water for billions of people, as glaciers disappear, the supply of drinking water is put at risk. However, remember that climate change is not the only variable in the equation, human patterns of water use and other factors also impact water supply (see research here and journalism coverage here and here). As glaciers fully retreat and disappear hydropower systems (dams that generate electricity) could become useless. While the initial flow of water from increased melting would benefit existing hydropower systems, when those glacial-fed rivers begin to dry up, so would the hydropower. Humans are not the only species that rely on glaciers as part of the ecosystem. Other species are also predicted to be negatively impacted by glacial loss (see a brief report on the research here).
Around the world, there are a few exceptions to the trend of retreating glaciers. These few cases of glacial stability or growth are caused by unique weather patterns that buffer some of the impacts of climate change.