Thawing glaciers are contributing to a rise in global sea levels and scientists are making clear how rapid and disastrous the consequences could be.
According to the latest research published in the journal “Nature,” scientists from the University of Zurich found that ongoing glacial mass loss accounts for 25 to 30 percent of the total observed sea level rise in recent times.
The data indicates that between 1961 and 2016 global glaciers lost more than 9,000 billion tons of ice, resulting in an increase of sea levels by 2.7 centimeters. The findings show the greatest contribution to the rising levels emanates from the melting of the glaciers in Alaska, followed by the ice fields in Patagonia and the polar regions.
Credit: ESA, adapted from Zemp & al. (2019) Nature & World Glacier Monitoring Service
“Globally, we lose about three times of the ice volume stored in the entirety of the European Alps – every single year,” says glaciologist Michael Zemp, who leads the research project. His team combined glaciological field observations with geodetic satellite measurements, which allowed them to reconstruct changes in the ice thickness of more than 19,000 glaciers worldwide.
About 68% of fresh water on Earth is stored in glaciers and ice caps, which comprise crucial fresh water sources to various regions.
In the Himalayas, changes to the cryosphere (snow, ice, permafrost) fuel the climate impact, affecting the timing and seasonal distribution of runoffs. This directly effects communities that depend on glacial water for subsistence.
The current glacier-melt water release also expands the potentially perilous glacier lakes, increasing the danger of flooding, and worsening permafrost degradation. Beyond that, such consequences can destabilize high mountain slopes and peaks. The resulting debris flows threaten local transportation infrastructure , posing further strains on local livelihoods.
The speed of glacial melting in Alps regions also concerns many scientists. According to the latest article published in the journal “The Cryosphere,” half of the glaciers within the region will disappear before 2050, despite the efforts being made to mitigate global warming.
Alps mountains are not just a tourist attraction, they function as reservoirs from which the fresh water is drawn for irrigation and electricity generation by the surrounding nations. Recently, the rarity of water resources resulting from shrinking glaciers has begun to change ecosystems and landscapes.
The reddish zone shows glacier retreat in Alps Credit: GLIMS and NSIDC (2005, updated 2018)
Why ice matters
Many experts connect the accelerating sea level rise to the unprecedented melting of ice caps covering Antarctica and Greenland. Once land ice melts, the water quickly floats into the oceans and increases its total volume. One common misconception that needs to be clarified is the myth that “melting sea ice contributes to the sea level rise.” This is incorrect.
“Melting sea ice has no impact on sea level rise because it’s already floating in the ocean,” explained Axel Schweiger, a researcher at the University of Washington. Just like a glass of ice water, once the ice melts, the total water volume stays the same. “However, melting sea ice does contribute to climate change.”
The reason for that is because white sea ice reflects the sunlight. When it gradually disappears, it forms a vicious climate cycle in which dark ocean water starts to absorb more sunlight, thus heating up and lifting the overall global temperature, which, at the same time causes more land ice to melt.
If no drastic action is taken to alleviate rising temperatures more disasters are foreseeable within this century: submerging island nations, devastating weather conditions, poverty, and famine all deriving from the harsher climate and scarce accessibility to fresh water.