In this new blog, Prof. Taras Gerya and Prof. Robert Stern synthesize recent advances in planetary geodynamics, the evolution of complex life, and the future of human civilization. They explore why continents and plate tectonics are essential for the emergence of technological species, and what this means for humanity’s own long-term survival and the likelihood of finding intelligent life elsewhere. Building on the emerging field of Biogeodynamics, their discussion offers deep introspection on our place in the galaxy, framed by new scientific insights into how planets, life, and civilization co-evolve.
Taras Gerya is a Professor of Geodynamics at ETH Zurich, specialized in Earth and planetary dynamics.
Exoplanets hosting technological civilizations are probably extremely unusual in the Milky Way galaxy. We may be the only one. Even if life does exist on exoplanets, the likelihood that it will evolve into a technological civilization – one capable of communicating across space – is extremely low. In our recent study (Stern and Gerya, 2024), we suggested that the evolution of technological civilizations is only possible on planets in the habitable zone with some kind of primitive life, which must evolve mostly in the ocean. However, development of complex intelligent, techno-savvy life (like us) also requires dry continents and plate tectonics to evolve (Video 1). Complex life has to evolve initially in an ocean, but must crawl out of the sea to evolve further. Land animals confront a continuously changing subaerial landscapes and conditions shaped by plate tectonics and surface processes that slowly change some of them to become capable of creating and using technologies reaching out beyond their home planet. That is what we humans have done.
Why are technological civilizations likely to be so rare in the galaxy? Biogeodynamic considerations provide an answer. Our calculations showed that no more than 1% of rocky planets are likely to have coexisting continents and oceans as only very tiny variations of surface water mass are permitted, which are easily violated by broad variations given by planetary accretion processes. Plate tectonics is also important, because it provides continuous and moderate pressure for organisms to compete, adapt, and evolve. This pressure is especially pronounced under subaerial conditions as water environments are much more interconnected. Plate tectonics is an unusual style of mantle convection and driving forces for it will only be available on less than 17% of terrestrial planets with water (Stern and Gerya, 2024). Hence, vanishingly few exoplanets with primitive life (<0.2%) are likely to have oceans, continents and plate tectonics (Video 2). Thus, based on reevaluation of the Drake equation, we concluded that human civilization may be alone in the galaxy (Stern and Gerya, 2024). Preserving it becomes humanity’s galactic responsibility (Gerya et al., 2026).
Bob Stern is a Professor of Geosciences and Director of the Global and Magmatic Research Laboratory at the University of Texas, Dallas
We are aware that our conclusions about the rarity of technological species in our galaxy is a minority viewpoint, but it certainly agrees with the lack of communications from other civilizations (the so-called Fermi paradox). If we are right, then the uniqueness of our civilization has profound cultural implications. Before Copernicus, Earth and humans were the center of the universe. After Copernicus, modern thought has emphasized humanity’s small place within an immense universe. For the past 150 years, science fiction has taken up the banner of “we’re nothing special”. Creation of books, movies, and videos on the many imagined advanced civilizations in our galaxy continue unabated today. If that was true, our demise would be no great loss because other civilizations would ensure that the exploration and colonization of the galaxy would continue. However, the extraterrestrial civilizations of science fiction are unlikely to exist. Exploration and colonization thus rests on our shoulders.
Video 1: Discussion on “The long-term survival of human civilization: a science-based paradigm.”
What is the societal implication of the potential uniqueness of technological intelligence in the galaxy? It is to recognize that the stakes of human long-term survival are astronomically high. If our civilization fails, the exploration and colonization of an entire galaxy could stop. Conversely, if we endure and thrive, we will preserve and propagate the only known spark of intelligent technological life in the Milky Way. This perspective impels us to begin developing a radical new, long-term, custodial mindset to ensure the long-term survival of human civilization. The timescales of interest are millions of years. We cannot imagine the progress in technology and civilization that will happen in a hundred years, so we cannot begin to imagine the future a million years from now. We can be sure, however, that the human exploration and colonization of the galaxy will be far advanced if our civilization persists so long.
How can our civilization survive on geological time scales? There are many things that we need to do and we are struggling with these now. In addition, we must align our civilization’s activities with Earth system dynamics, tempos and cycles rather than acting against them. In contrast to humanity’s strong impact on landscape, oceans and atmosphere, we have no discernible effect on the solid Earth system, including plate tectonics and mantle plumes, which control the pace of the carbon cycle and natural resources creation and destruction.
Video 2: Discussion on the key role of oceans, continents, and plate tectonics in shaping life and civilizations.
What does “aligning with Earth’s dynamics” mean in practice? It means basing our policies on a sound understanding of Biogeodynamics (https://biogeodynamics.com) and acting within the planetary boundaries that maintain long-term stability. Four efforts are important. First, we must address anthropogenic climate with deep time in mind. We must limit atmospheric CO₂ to levels that avoid passing irreversible climate tipping points we cannot control. A second effort to align civilization with Earth’s dynamics would be to learn from past climate crises. By studying important climate crises such as ice ages and past greenhouse episodes, we can use this knowledge to better deal with current and future challenges and changes. A third effort emphasized caution as we geoengineer. Geoengineering projects need to be carefully considered for long-term consequences before implementation using lessons learned from Earth’s past changes. Finally, aligning with Earth’s dynamics also means respecting that nature has its own pace. While technology moves fast, ecological and geological processes are slow. We must find ways to moderate our demands on ecosystems as well as on mineral resources so that our civilization can co-evolve with both the deep Earth and the biosphere.
… a new scientific discipline called “Future Dynamics”
Above all, knowledge created by experts and transmitted to the public and policymakers is needed to face these unprecedented challenges. Therefore, we propose to build a new scientific discipline called “Future Dynamics”. This transdisciplinary field would focus on understanding, modeling and quantifying the potential coupled biogeodynamical evolution of the Earth-Life-Human system over geological timescales. Our central priority should be to ensure the long-term survival of civilization, maintaining continuity of increasing knowledge, technology, and planetary stewardship into the deep future, so that our work in the galaxy can continue. This requires aligning our society with Earth’s biogeodynamical system, learning from the past, and committing to a path of sustainability and resilience. It also calls for innovation in how we think, learn, teach and plan – embracing a new Future Dynamics perspective that transcends short-term political and societal considerations. In doing so, we fulfill a responsibility not just to our children or grandchildren, but to the entire chain of life and consciousness that hopefully will emanate from our actions, stretching millions of years ahead. The long-term survival of human civilization is the bedrock upon which all other aspirations rest – and it is a mission worthy of our greatest efforts.
References
Gerya, T.V., Stern, R.J., Turner, F., & Roman, S. (2026). The long-term survival of human civilization: a science-based paradigm. Habitable Planet, 2, 1–13. (Video 1, 18 min) Stern, R.J., & Gerya, T.V. (2024). The importance of continents, oceans and plate tectonics for the evolution of complex life: implications for finding extraterrestrial civilizations. Scientific Reports, 14(1), 8552. (Video 2, 8 min) Further resources: https://biogeodynamics.com Video 3 (interdisciplinary workshop on earth, environment and healthy living 2025) : https://www.youtube.com/watch?v=jP-7ExYW6jE
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