What is it about?
During the last ice age, Greenland’s climate repeatedly swung abruptly between cold and warmer phases. Dust trapped in Greenland’s ice reveals where the winds carried it from, but until now it was not possible to trace how dust sources changed through these abrupt swings. We identified the sources of dust in closely spaced samples from a Greenland ice core across the whole last glacial period. East Asian deserts were always the main source, but a larger share of the dust came from the Sahara during cold phases, as the westerly winds and the tropical rain belt moved south and trade winds strengthened. This shows that the dust cycle shifts along with abrupt climate change.
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Photo by Agnieszka Bednarz on Unsplash
Why is it important?
Dust plays an important role in Earth’s climate. It scatters sunlight, helps clouds form, darkens snow and ice surfaces, and supplies iron that fuels ocean plankton growth. Our findings show that the high-latitude Northern Hemisphere dust cycle, including where dust comes from, shifted along with the abrupt climate changes of the last ice age. These results provide a benchmark for testing and improving the climate models used to simulate dust. With Earth now undergoing rapid climate change, such models can help us understand how the dust cycle may change in the future and how those changes could further affect climate.
Perspectives
This study was especially rewarding for me because it built on our team’s earlier work, which suggested that Saharan dust could reach Greenland more easily during the Last Glacial Maximum, as atmospheric circulation changed in a colder climate. Professor Sungmin Hong, my PhD supervisor and the initial corresponding author of this study, then raised the question of whether the same mechanism also operated during the abrupt climate swings of the last ice age. I was delighted to find that it did. Sadly, Professor Hong (1961–2026) passed away on July 9, 2026, before he could see this work published. This work is dedicated to his memory. Professor Hong made substantial contributions to reconstructing past climate and pollution histories and to tracing the sources of atmospheric pollutants and mineral dust, using geochemical and isotopic records preserved in ice cores. Beyond his science, he will be remembered for his warmth, generosity, and genuine care for those around him. He supported his students not only in their research but throughout their personal and professional lives. His mentorship and enduring scientific legacy will continue to inspire me and all his students.
Seokhyun Ro
Read the Original
This page is a summary of: Millennial-scale variability in Greenland dust provenance during Dansgaard–Oeschger events of the last glacial period, Proceedings of the National Academy of Sciences, November 2026, Proceedings of the National Academy of Sciences,
DOI: 10.1073/pnas.2618898123.
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