New scientific studies provide strong evidence that glaciers are among the most sensitive indicators of the deposition of atmospheric carbon. Together these provide an extraordinary opportunity for scientists to assess human impacts on the environment. In a 2023 study, lead author Amy D. Holt and her colleagues looked closely at dissolved organic matter, or DOM, in meltwater. They zoomed in on samples from ten glaciers across Alaska, Switzerland, Kyrgyzstan, and Ecuador. Based on those results, researchers recently published their recommendations in the journal Global Biogeochemical Cycles. They showed how human-made pollution is disrupting the carbon cycle in these essential ice masses.
The researchers discovered that glaciers had widely different concentrations of dissolved organic carbon. These disparities associated with anthropogenic atmospheric pollution were between 12%-91%. The median percentage of dissolved organic carbon that could be attributed to anthropogenic sources was 50%. This large range highlights the different levels of pollution and environmental alterations that are impacting glaciers globally.
Research Methodology and Findings
Holt and her team wanted to focus on the meltwater carbon’s origins within a glacier. This far-reaching study required the collection of samples from ten different glaciers, each impacted by unique surrounding environments and levels of pollution.
Mendenhall Glacier in Alaska was one of the flagship glaciers compared in this study. The team’s findings, published in Nature Communications, provide new insights into the role of dissolved organic matter from these glaciers in global carbon cycling. Their study powerfully demonstrates the ways in which glaciers export dissolved organic matter. Finally, they conclude by emphasizing the need to track these shifts moving forward.
“New research examines the sources of carbon in glaciers, such as those exported from Mendenhall Glacier, Alaska.” – Amy Holt
Variations in Carbon Sources Across Locations
The study found geographic differences in how much carbon various sources contributed as well. In Ecuador, for example, researchers noted a higher relative contribution of carbon from biomass burning, including wildfires, alongside in situ microbial activity. This result indicates that there are distinct, local environmental conditions involved in driving changes to carbon dynamics in glacier systems.
Glaciers from the Northwest United States and Norway showed more varied carbon source profiles. This new study highlights the importance of understanding local contexts that shape atmospheric carbon deposition. Perhaps more importantly, it is a reminder of the lively push and pull between natural processes and human use.
Implications for Climate Research
The discoveries obtained through the research hold precedent-setting ramifications for climate science and environmental policy. It’s important to understand how glaciers are responding to anthropogenic pollution. It offers key data to help calibrate climate models and allows scientists to project changes in global ecosystems in the future.
As rising temperatures make their retreat deeper and deeper into the earth’s crust, their role as the planet’s climate change early warning system only grows more important. They hold critical clues to what our carbon past looked like. They aid researchers in understanding chronic trends in fossil fuel pollution.