Hidden in the thick, muddy layers of ancient bogs across the Southern Hemisphere is a surprising record of Earth’s climate history.
New research suggests that a dramatic shift in powerful southern winds around 15,000 years ago helped trigger the widespread growth of these peatlands—natural ecosystems that play a major role in storing carbon and regulating the planet’s climate.
The study, led by scientists from the University of Southampton and published in Nature Geoscience, looked at peat samples from South America, Australasia, southern Africa, and remote sub-Antarctic islands.
By carefully analysing these samples and using radiocarbon dating, the researchers were able to determine when these wetlands began forming after the last Ice Age.
Peatlands develop in waterlogged environments where dead plants slowly pile up and do not fully decompose.
Over thousands of years, this process locks away huge amounts of carbon in the ground. Today, peatlands store more carbon than all the world’s forests combined, making them one of Earth’s most important natural carbon sinks.
Until now, scientists were unsure what caused peatlands to suddenly expand across such a wide area in the distant past.
The new research points to changes in the Southern Westerly Winds—the strong winds that circle the Southern Hemisphere between the mid-latitudes and Antarctica.
According to Dr. Zoë Thomas, the lead author of the study, these winds shifted north about 15,000 years ago as the planet was emerging from the last Ice Age. This movement changed weather patterns and ocean circulation in a way that created wetter conditions across large parts of the Southern Hemisphere. Those wet conditions were perfect for the formation and expansion of bogs and peatlands.
The shift in winds also affected the Southern Ocean, which is the largest natural absorber of carbon dioxide on Earth. When the winds change direction, they alter how the ocean mixes and how much carbon it can take in or release into the atmosphere. At the time when peatlands were rapidly expanding, carbon dioxide levels in the atmosphere were also changing, suggesting a strong link between wind patterns, ocean behaviour and the global carbon cycle.
What makes this discovery especially important is that the Southern Westerly Winds are moving again today—but in the opposite direction. Due to modern climate change, these winds are shifting closer to the South Pole. Scientists have already observed that this southward movement is contributing to droughts, higher temperatures, and more frequent wildfires in regions like Australia, South America, and southern Africa.
Dr. Haidee Cadd, a co-author of the study from the University of Wollongong, warns that if these winds continue to move south, the Southern Ocean may become less effective at absorbing carbon dioxide. That would mean more CO₂ remaining in the atmosphere, which could accelerate global warming.
By studying ancient bogs and the clues locked inside them, scientists are learning how sensitive Earth’s climate system is to changes in wind patterns.
These insights are not just about the past—they are valuable warnings about what could happen in the future if current trends continue.
