In a study conducted by the University of Wisconsin’s Proglacial Lab, Dr. Shaun Marcott’s team has discovered that tropical glaciers in the Andes Mountains are now smaller than they have been at any point since the last ice age, approximately 12,000 years ago. This finding serves as a stark warning about the accelerating pace of climate change and its far-reaching consequences said Dr. Luke Zoet, a contributor to a study by Nature Geoscience.
The study, published by Nature Geoscience, utilized cutting-edge data techniques to analyze rock samples from four glaciers in the Bolivian Andes. Zoet said that by measuring the accumulation of UV rays in these samples, the researchers reconstructed a detailed history of glacier retreat and advance over millennia.
Marcott’s team chose to focus on tropical glaciers in the Andes for several reasons. The Andes were selected due to its size and geographical position, Zoet said.
The models show that the Andes glaciers are very sensitive to climate change, Zoet said. The equatorial location and high altitude of these glaciers make them ideal indicators of global climate trends, removing some of the complexities found in other regions.
“It seems counterintuitive, but what happens is if you have a big glacier… they are slow to respond to the climate because of the massive mass,” Zoet said.
The study’s findings are particularly significant because they place the current glacier retreat in a broader historical context. While there have always been fluctuations in glacier size, the recent retreat is far greater than anything observed in the past 12,000 years, Zoet said.
This unprecedented shrinkage has profound implications for local communities and ecosystems. These glaciers provide massive amounts of resources for these communities. In the summer the Andes glaciers serve as their water supply, Zoet said.
While the study focused on just four glaciers in the Andes, its implications extend far beyond South America. Ph.D. student for the Proglacial Lab Andrew Jones describes these glaciers as a “canary in the coal mine for climate change,” suggesting that larger glaciers worldwide may soon follow a similar pattern.
Though this glacier itself will not have worldwide effects, it provides insight for how everything from water resources and agriculture to sea level rise and coastal infrastructure could be impacted, Jones said. It is vital for scientists to work with people that are studying the physics of glaciers and they need to work with coastal processes. These include city planners, coastal managers and local government officials, Zoet said.
Conducting this research was no easy feat. The team faced significant logistical challenges due to the extreme altitudes involved — often around 16,000 feet. At such heights, both researchers and equipment struggle to function optimally. There was a need for massive collaboration between American scientists, Bolivian scientists and local government officials to make certain that Indigenous and local communities are unaffected, Jones said.
“There are logistic challenges in physically getting there, by virtue of how glaciers exist in these tropical areas,” Zoet said. “[Glaciers] have to be very high in altitude which is hard.”
The study employed an innovative method, likened to measuring how “sunburnt” rocks become when exposed, Zoet said. By analyzing the accumulation of certain minerals and isotopes in bedrock samples, the team could determine how long the rocks had been exposed or covered by glaciers, Zoet said. This indicates just how fast the glaciers have retreated.
In light of these findings, the researchers stress the urgent need for climate action at both national and international levels. Carbon dioxide is the main greenhouse gas, which is a global issue that U.S. emissions directly affect the tropics, Jones said.
“Climate action needs to happen at the government level,” Jones said. “And the United States has to be leading.”
Recent developments, such as the U.S. rejoining the Paris Accords and passing the Inflation Reduction Act (IRA), are seen as positive steps, but much more work remains to be done. The Paris Accords aimed to limit global warming to preindustrial levels, strengthen the collaboration between countries and provide assistance to less developed countries to mitigate climate change effects, according to the State Department. The IRA commits to clean energy provisions, emissions reduction, clean energy tax credits, electric vehicle incentives, energy rebates and an emphasis on environmental justice, according to The White House.
This study serves as a powerful reminder of the interconnectedness of our global climate system and the urgent need for comprehensive action to address the climate crisis, according to Jones.