In Alaska, many rivers are turning bright orange, a change not due to pollution but to natural processes. As permafrost thaws, iron from the soil seeps into rivers, giving them a rusty color. This phenomenon, known as “rusting rivers,” has spread across the Brooks Range. It highlights the tangible impacts of climate change in a region warming faster than the global average.
The latest Arctic Report Card from the National Oceanic and Atmospheric Administration (NOAA) shows that last year was the warmest and wettest on record for the Arctic. Matthew Druckenmiller, a senior scientist at the National Snow and Ice Data Center, emphasizes that Arctic changes affect global sea levels, weather patterns, and fisheries. “When the Arctic thaws, it impacts the entire planet,” he says.
A notable aspect of warming in the Arctic is the rising incidence of rusting rivers. These rivers were first noticed around 2018, as reported by Josh Koch of the U.S. Geological Survey. He recalls hearing from local pilots and park visitors who observed these striking transformations. Satellite images and ground tests have confirmed that hundreds of miles of rivers show elevated levels of iron and other heavy metals, due to thawing permafrost.
Koch explains that as permafrost melts, water and oxygen mix with the soil, releasing iron and metals into rivers. This release can happen quickly, transforming clear streams into discolored waterways in just days. Other harmful metals may also enter these rivers. While scientists are studying potential effects on local fish and drinking water, no immediate impacts have been observed yet.
Another significant change is the rapid loss of glaciers. The Greenland Ice Sheet, for example, lost about 129 billion tons of ice in a single year—an alarming statistic that contributes to rising sea levels globally. Glaciers in Alaska have thinned significantly over the last few decades, with some losing an average of 125 vertical feet since the 1950s. These changes pose immediate threats, such as glacial outbursts causing floods, as seen with the Mendenhall Glacier incident near Juneau.
The Arctic is also undergoing “Atlantification,” where warmer and saltier water from the Atlantic is entering Arctic waters. This change is linked to record low sea ice levels in the region. The lowest extent of sea ice was observed in 2023, a trend that has serious implications for marine ecosystems. Warmer waters in the Bering Sea are pushing traditional Arctic species out and inviting southern species in, disrupting local fishing practices and traditional hunting. As Druckenmiller states, “The food chain is interwoven with the lives of Arctic communities.”
The findings from the annual Arctic Report Card offer a sobering glimpse into the significant changes underway in this crucial region. They highlight the importance of sustained research and monitoring to understand and address the rapid impacts of climate change. For more details, you can check NOAA’s official webpage on the Arctic Report Card.
