Folks, hold onto your hats—two groundbreaking studies dropped this past month, and they’re shaking up everything we thought we knew about carbon dioxide (CO2) in Earth’s atmosphere. The first, from The University of Manchester, reveals that volcanic CO2 emissions could be three times higher than previously estimated. The second, from the School of Ocean and Earth Science and Technology (SOEST), uncovers a staggering 19,325 previously unknown undersea volcanoes. Together, these findings throw a massive wrench into the narrative that human activity is the sole driver of rising atmospheric CO2. Let’s dive in.

Manchester’s Volcanic CO2 Bombshell might be a game changer. The Manchester team, led by Alexander Riddell, deployed cutting-edge sensors on a helicopter to measure emissions from the Soufrière Hills Volcano in Montserrat. Published in Science Advances DOI: 10.1126/sciadv.ads8864, their findings are a wake-up call. Traditional monitoring focused on hot volcanic vents (fumaroles) that spew easily detectable gases like sulfur dioxide (SO2). But cooler, water-rich hydrothermal systems absorb acidic gases, masking significant CO2 output. The new tech revealed that Soufrière Hills emits three times more CO2 than earlier estimates suggested.

Riddell notes, “Volcanoes play a crucial role in the Earth’s carbon cycle,” but he’s quick to downplay the impact, claiming volcanoes contribute less than 5% of global CO2 compared to human activities like fossil fuel burning. Fair enough, but if one volcano’s emissions are underestimated by a factor of three, what about the thousands of others worldwide? The study hints at a broader issue: our volcanic CO2 estimates could be way off, especially for volcanoes with similar hydrothermal systems.

Meanwhile, researchers at SOEST, including Paul Wessel and Scripps’ David Sandwell, used high-resolution radar satellite data to map the ocean floor. Their study, published in Earth and Space Science, identified 19,325 new seamounts—undersea volcanoes—bringing the total to over 43,000 SOEST News. With only a quarter of the seafloor mapped by sonar, most of these underwater giants remain uncharted. These seamounts aren’t just geological curiosities; they’re potential CO2 sources, stirring ocean currents and influencing carbon cycles.