Rapid advances in space technology, synthetic biology, and climate modeling have reignited scientific debate over terraforming Mars, shifting the idea from science fiction toward a long-term research question with profound ethical implications.

Terraforming is the theoretical process of altering a planet’s environment—its atmosphere, temperature, and climate—so it can support human life and Earth-like ecosystems. Among all planets in the solar system, Mars has emerged as the most frequently discussed candidate, due to its relative proximity and evidence of water ice beneath its surface.

For decades, scientists largely dismissed the idea as technologically impossible. But an international group of researchers led by Dr. Erika DeBenedictis of Pioneer Labs is reconsidering that assessment.

In a workshop summary prepared for the upcoming 2025 Green Mars Workshop, DeBenedictis argued that terraforming should be studied as a legitimate scientific research program—not as an immediate goal, but as a framework for understanding what might be possible in the distant future.

“Thirty years ago, terraforming Mars was not just difficult—it was effectively impossible,” DeBenedictis wrote. “Today, advances across multiple fields have fundamentally changed the conversation,” he added.

Lower launch costs, new biology

The researchers point to several developments that have reshaped the debate. These include potential reductions in launch costs through next-generation spacecraft such as SpaceX’s Starship, major advances in synthetic biology, and improved climate modeling capabilities.

Researchers shifted their discussions from whether terraforming violates the laws of physics toward more complex questions. How could it be done? Over what timescale? And should it be done at all?

Rather than proposing a single solution, the team outlined a phased pathway toward a more habitable Mars.

A staged vision for Mars

The first phase would focus on warming the planet. Scientists suggest that Mars’ average temperature could be increased by several tens of degrees Celsius within decades by releasing specially engineered greenhouse gases or aerosols.

Studies indicate that Mars contains enough frozen water to form an ocean covering nearly four million square kilometers, with an average depth of about 300 meters. A global temperature increase of around 30 degrees Celsius could allow this ice to melt, enabling liquid water to persist on the surface.

The second phase would introduce life at the microscopic level. Using synthetic biology, researchers envision designing extremophiles—microorganisms engineered to survive intense radiation, extreme cold, and low atmospheric pressure. Once deployed, these microbes could spread across the planet within decades, gradually altering the atmosphere through photosynthesis.

The final phase would unfold over centuries or even millennia. The goal would be to build an oxygen-rich atmosphere capable of supporting complex life. This process could begin inside massive domed habitats, some up to 100 meters tall, where oxygen would be generated through photosynthesis or water electrolysis. Over time, plant life could expand beyond these structures, slowly contributing oxygen to the wider Martian atmosphere.

Scientific gaps and ethical concerns

The researchers also highlighted major unanswered questions. What lies beneath Mars’ extensive ice sheets? How would dust storms behave in a warmer, wetter environment? Are the materials necessary for large-scale oxygen production abundant on Mars?

Beyond technical challenges, ethical concerns loom large. Terraforming would permanently alter Mars, potentially destroying a pristine geological record critical to understanding planetary history. If indigenous Martian life exists, even in microbial form, human intervention could erase it before it is discovered.

Still, the team argues that studying terraforming could yield immediate benefits for Earth. Technologies developed for sustaining life on Mars. These technologies include closed-loop ecosystems, drought-resistant crops, and highly efficient energy systems, which could be adapted to address climate and sustainability challenges on the home planet.

“Learning how to make Mars habitable,” the researchers said, “may also help us learn how to better protect the only habitable world we currently have.”