How Ancient Carbon Emissions from Rivers Are Shaping Climate Change Predictions

A recent study uncovered that ancient carbon, trapped in landscapes for ages, is leaking back into the atmosphere as carbon dioxide (CO2) from rivers. This groundbreaking research, led by scientists from the University of Bristol, was featured in the journal *Nature*.

The study reveals that plants and shallow soil layers are likely absorbing an extra gigatonne of CO2 each year to balance this release, highlighting their crucial role in fighting climate change. Dr. Josh Dean, the lead author, shared, “We were surprised by these results. It turns out more old carbon is escaping into the atmosphere than we thought.” He emphasized that this finding changes how we think about global carbon emissions.

Traditionally, scientists believed that the majority of carbon emissions from rivers came from recently decayed plants. However, this study indicates that about 60% of the emissions are linked to long-term carbon stores that have accumulated over hundreds or even thousands of years.

The research team analyzed over 700 river sites in 26 countries, measuring carbon dioxide and methane levels. They used radiocarbon dating to distinguish between new and ancient carbon. Co-author Prof. Bob Hilton explained that approximately half of the river emissions are from deep soil layers and weathered rocks formed long ago.

Dr. Gemma Coxon, another co-author, pointed out that rivers release roughly two gigatonnes of carbon annually. This is significant compared to the 10-15 gigatonnes produced by human activities. “We need to rethink how these ancient carbon stores fit into the global carbon cycle,” she noted.

Looking ahead, the researchers plan to investigate how the carbon age varies across different rivers and how this might change over time. This study opens new avenues for understanding carbon emissions and emphasizes the importance of preserving our natural landscapes to combat climate change.

For a deeper dive into the global carbon cycle and ongoing studies, check out resources from the [Natural Environment Research Council (NERC)](https://www.ukri.org/our-impact/what-is-the-natural-environment-research-council/) and similar authoritative bodies.

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