Volcanic activity may have given rise to life on Mars, according to a University of Texas at Austin-led research team investigating how a greenhouse-like effect on the Red Planet long ago could have produced habitable conditions.
The early Martian climate remains a mystery to planetary scientists, but Martian meteorites offer some clues. In a new study published in Science Advances, computer modeling was used to help make predictions about the climate of ancient Mars, which would have been favorable to simple life.
Modeling A Climate for Life on Mars
The team conducted 40 simulations, modeling the chemistry, concentrations, and temperatures of early Mars to estimate the presence of carbon, nitrogen, and sulfur-based gases. The results contradicted earlier studies that pointed to a sulfur dioxide–rich atmosphere. Instead, the models suggested sodium sulfide, disulfur, and potentially sulfur hexafluoride dominated. These chemically reduced forms of sulfur are highly reactive, with sulfur hexafluoride acting as a powerful greenhouse gas. This unexpected mix, the team says, may have created conditions suitable for life.
“The presence of reduced sulfur may have induced a hazy environment which led to the formation of greenhouse gases, such as SF6, that trap heat and liquid water,” said lead author Lucia Bellino. “The degassed sulfur species and redox conditions are also found in hydrothermal systems on Earth that sustain diverse microbial life.”
Volcanic Atmosphere
Researchers have long considered how volcanic eruptions shaped Mars’s atmosphere, but this study is the first to focus on how geologic processes altered the sulfur released. The analysis looked at how sulfur separated from other materials and merged into magma beneath the Martian crust.
Understanding these processes helps explain what types of sulfuric gases were released and how they contributed differently to the early Martian climate. Today, sulfur samples collected on Mars vary depending on location: surface samples often show sulfur bonded with oxygen, while meteorites contain large amounts of reduced sulfur.
“This indicates that sulfur cycling – the transition of sulfur to different forms – may have been a dominant process occurring on early Mars,” Bellino said.
Curiosity Discovers Sulfur
NASA’s Mars Curiosity rover offered supporting evidence last year when it broke open a Martian rock and revealed elemental sulfur inside—the first discovery of pure, unbound sulfur on the planet.
“We were very excited to see the news from NASA and a large outcrop of elemental sulfur,” said co-author Chenguang Sun. “One of the key takeaways from our research is that as S₂ was emitted, it would precipitate as elemental sulfur. When we started working on this project, there were no such known observations.”
Continuing the Search for Life on Mars
The University of Texas team plans to expand their simulations to examine Mars’s water cycle and other climate factors. They aim to understand whether volcanic activity could have generated large surface water reservoirs and whether sulfur could have served as a food source for ancient microbes, much like ecosystems around hydrothermal vents on Earth.
While today’s Mars averages a frigid –80°F, the modeled greenhouse emissions could have significantly warmed the young planet. The researchers hope their work will clarify just how warm ancient Mars may have been, and whether microbial life could have survived there.
The paper, “Volcanic Emission of Reduced Sulfur Species Shaped the Climate of Early Mars,” appeared in Science Advances on September 3, 2025.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.