Introduction: Astrophysicist Adam Frank from the University of Rochester, along with David Grinspoon from the Planetary Science Institute and Sara Walker from Arizona State University, conducted a so-called "thought experiment" to explore a broad question using scientific theories: what impact does life have on a planet? Based on their research, they propose a description of Earth's past and possible future through four stages. This article is a translation of the phys.org article "Can a planet have a mind of its own?" from the University of Rochester (February 16, 2022), which provides a brief summary of the research paper "Intelligence as a planetary scale process".
The collective activities of all organisms on Earth, including microorganisms, plants, and animals, have already changed the planet.
Take plants as an example: in order to enhance their survival capabilities, plants "invented" a way to carry out photosynthesis. However, at the same time, they also release oxygen, which has changed the overall functioning of our planet. A single category of life form can have planetary-scale effects by simply carrying out its own tasks, and plants are just one example.
If the collective activities of organisms (also known as the biosphere) can change the world, can collective cognitive activities and behavior based on cognition also change a planet? Once the biosphere evolves, the Earth itself possesses life. If a biotic planet has life, does it also have a mind?
This is the question posed by Adam Frank, David Grinspoon, and Sara Walker, whose research findings have been published in the journal "International Journal of Astrobiology". (Adam Frank is the Helen F. and Fred H. Gowen Professor of Physics and Astronomy at the University of Rochester.) They refer to their research as a "thought experiment" that combines current knowledge of Earth and explores broader questions about how life changes a planet. In their paper, the researchers discuss what they call "planetary intelligence," which refers to cognitive activities operating on a planetary scale, and propose new ideas for addressing global issues such as climate change.
Frank says, "If we want to ensure the continuity of our own species, we must use our intelligence to create greater well-being for this planet."
An "Immature Technosphere"#
Frank, Grinspoon, and Walker drew inspiration from ideas such as the Gaia hypothesis. The Gaia hypothesis suggests that the biosphere interacts closely with non-living geological systems such as the atmosphere, water, and land in order to maintain a suitable environment for life. Through this, researchers explain that even species without technological capabilities can exhibit planetary intelligence. The key here is that the collective activities of organisms create a self-sustaining system.
Frank gives an example: recent studies have shown that tree roots in forests are connected through an underground fungal network called mycorrhizal networks. If one part of the forest needs nutrients, other parts will transport the necessary nutrients through the mycorrhizal network. In this way, the forest can sustain itself.
These researchers refer to our current civilization as an "immature technosphere" - a collection of human-made systems and technologies that directly impact the Earth but cannot sustain themselves. For example, most of the energy we use comes from burning fossil fuels, which has negative effects on the Earth's oceans and atmosphere. The technologies and energy we rely on are destroying our home planet, which in turn further threatens our own species.
In order to ensure the continuity of our species, we need to come together and act for the well-being of the Earth.
However, Frank states, "We do not yet have the ability to collectively respond to the greater well-being of the Earth. There is intelligence on Earth, but not yet planetary intelligence."
Moving towards a Mature Technosphere#
To illustrate the role that planetary intelligence could play in the long-term future of humanity, the researchers divided Earth's past and possible future into four stages. They also demonstrated the evolutionary pathways of these stages driven by planetary intelligence. They believe that planets in the universe that have successfully evolved life and sustainable technological civilizations may possess these characteristics.
Stage 1: Immature Biosphere: This represents the early characteristics of Earth, billions of years ago, before the emergence of technological species. Microorganisms already existed at that time, but plants had not yet appeared. At this stage, global feedback was minimal because life did not possess the power to significantly influence planetary systems such as the atmosphere and hydrosphere.
Stage 2: Mature Biosphere: This represents the characteristics of Earth before the emergence of technological species, from approximately 2.5 billion years ago to 540 million years ago. Stable landmasses had formed, vegetation and photosynthesis were widespread, oxygen had accumulated in the atmosphere, and the ozone layer had formed. The biosphere had a significant impact on Earth and may have contributed to maintaining a habitable environment for life.
Stage 3: Immature Technosphere: This represents the current characteristics of Earth, where interconnected communication, transportation, technology, electricity, and computer systems exist. However, the technosphere is still immature as it has not yet integrated with other Earth systems such as the atmosphere. Instead, it extracts resources and energy from the Earth's systems, leading to a new state that is not suitable for this technosphere as a whole. In the long run, our current technosphere is harmful to itself.
Stage 4: Mature Technosphere: Frank suggests that the future goal of Earth should be to develop beneficial technological systems that do not harm the biosphere, such as collecting solar energy on a global scale. A mature technosphere should coevolve with the biosphere, ultimately creating a mutually beneficial system between the technosphere and the biosphere.
"Planets evolve from an immature stage to a mature stage, and planetary intelligence is a sign of entering the mature stage," says Frank. "Exploring the true nature of planetary intelligence is an invaluable topic and has significant practical implications for ourselves, as we still do not know how to develop into a mature technosphere." Currently, Earth is in the "immature technosphere" stage, as most of the energy and technology we use have negative impacts on Earth's atmosphere and other systems. Frank states that in order to ensure the continuity of our species, we must strive to reach the "mature technosphere" stage, where humanity possesses a technological system that benefits the entire planet.
Complex Planetary Intelligence System#
Although we currently do not know how planetary intelligence may manifest, these researchers state that a mature technosphere involves integrating technological systems with the Earth, requiring a complex system of feedback loops.
In simple terms, a complex system is one composed of interacting components, and their interactions determine the overall behavior of the system. In other words, the whole exceeds the sum of its parts. There are many examples of complex systems, such as forests, the internet, financial markets, and the human brain.
Fundamentally, individuals in a complex system exhibit emergent properties during their interactions, properties that individuals themselves do not possess. For example, it is difficult to determine a person's personality by examining individual neurons in their brain.
This means that it is difficult to predict the characteristics that may emerge when individuals form planetary intelligence. However, these researchers believe that complex systems like planetary intelligence will inevitably have two characteristics: emergent behavior and the ability to self-sustain.
"The biosphere created a system for transporting nitrogen and carbon billions of years ago, which was its way of finding self-sustainability," says Frank. "Now we must find a way to make the technosphere also possess similar self-sustaining characteristics."
Searching for Extraterrestrial Life#
Although humans have made some efforts, including global bans on certain environmentally harmful chemicals and increased use of solar energy, Frank says, "We still do not have planetary intelligence or a mature technosphere, but the purpose of this research is to indicate the direction we should move in."
Frank states that posing these questions not only provides information about the past, present, and future of life on Earth but also helps in the search for life and civilizations beyond our solar system. For example, Frank is also the principal investigator of a NASA project searching for technological signatures of civilizations around distant stars.
"It can be said that the only technological civilization we may encounter - the technological civilization we expect to encounter - is one that has not killed itself, meaning that they must have reached a true stage of planetary intelligence," he says. "This is the contribution of this research: it connects our knowledge of surviving the climate crisis with what may happen on other planets where life and intelligence have evolved."