Detectability of Future Earth

This special issue of the journal Futures features papers that examine the future of Earth and civilization from an astrobiological perspective, particularly focused on the extent to which human activities could be detectable across interstellar distances. As the guest editor of this special issue, my paper “Introduction: Detectability of future Earth” provides a synthesis of all the contributions in the volume.

This collection of papers demonstrates an important connection between futures studies and the search for extraterrestrial intelligence. The first issue is to examine possible future trajectories for human civilization: our growth in population and energy consumption will eventually face limits, even with advances in technology. This hybridization of the planet with technology is uncharted territory in Earth’s history, with an uncertain future or trajectory. The second issue is whether or not any other civilizations in the galaxy have already passed through this trajectory by achieving a sustainable hybridization of technology with their own planet. Evidence of such civilizations would be good news for humanity, as this would mean that our own future includes viable options for longevity. But if the search for extraterrestrial life turns up nothing, then this may indicate that energy-intensive civilizations might not be sustainable at all on a galactic scale. Our challenge as a species is to critically examine our possible futures and identify strategies for increasing the longevity of our civilization.

The collection of papers from this special issue on the Detectability of Future Earth is available on the Futures website.


Jacob Haqq-Misra (2019) Introduction: Detectability of future Earth, Futures 106: 1-3.
This special issue emphasizes the connection between the unfolding future of the Anthropocene with the search for extraterrestrial civilizations.

Brendan Mullan & Jacob Haqq-Misra (2019) Population growth, energy use, and the implications for the search for extraterrestrial intelligence, Futures 106: 4-17.
Limits to growth in population and energy consumption could occur within 2-3 centuries, which might imply that energy-intensive extraterrestrial civilizations are also rare.

Gina Riggio (2019) Earth in Human Hands, by David Grinspoon., Futures 106: 18-19.
This book review highlights Grinspoon’s observation that we are entering a new epoch of planetary self-awareness.

Julia DeMarines (2019) Light of the Stars: Alien Worlds and the Fate of the Earth, by Adam Frank., Futures 106: 20.
This book review highlights the connections between the future of Earth and the possibility of extraterrestrial civilizations.

Carl L. DeVito (2019) On the Meaning of Fermi’s paradox, Futures 106: 21-23.
This mathematical treatment of the Fermi paradox suggests that civilizations in the galaxy may emerge very slowly.

S. Stoney Simons & Jacob Haqq-Misra (2019) A trip to the moon might constrain the Fermi Paradox, Futures 106: 24-32.
Building a lunar observatory at mid-infrared wavelengths could help to improve the search for biosignatures.

Jacob Haqq-Misra (2019) Policy options for the radio detectability of Earth, Futures 106: 33-36.
Earth’s future radio detectability depends upon the risks we assume about the possibility of extraterrestrial contact.

Sanjoy M. Som (2019) Common identity as a step to civilization longevity, Futures 106: 37-43.
Civilization can extend it’s longevity through early-childhood psychology education based upon the “overview effect” of observing Earth from space.

The Risk of Transmitting to Space

The idea of messaging to extraterrestrial intelligence (METI) suggests that a possible way to establish contact with civilizations on other planets is to first send transmissions ourselves. The search for extraterrestrial intelligence (SETI) has traditionally followed a passive listen-only mode to detect any alien transmissions headed our way. If everyone is listening and nobody is transmitting, then METI might be the way to attract attention.

But is attracting attention from extraterrestrial civilizations necessarily good? We have no idea if contact with extraterrestrial beings would benefit or harm humanity, or even be completely neutral in its impact. Some scientists are unconcerned about possible risks and suggest that METI transmissions should occur whenever they are viable. Others worry that METI transmissions could expose Earth to significant risk and argue in favor of a moratorium on METI activities.

I recently published a paper titled “Policy options for the radio detectability of Earth” in the Futures special issue on the Detectability of Future Earth. In this paper, I argue that the METI risk problem cannot be conclusively decided until contact with extraterrestrial intelligence actually occurs. This implies that any moratorium on METI activities cannot be based on the requirement for new information, as the only new information that would actually suffice is the actual discovery of alien life. Following from this conclusion, there are three possible policy options for proceeding with SETI and METI:

  1. Precautionary malevolence – alien contact is likely to be harmful, so we should not engage in METI until SETI succeeds.
  2. Assumed benevolence – alien contact is likely to be helpful, so we should engage in METI along with SETI.
  3. Preliminary neutrality – alien contact is unlikely to occur at all, so we may as well do SETI and METI if funds are available.

All three of these policies remain viable options until we actually discover extraterrestrial intelligence and learn the actual risks to humanity. Precautionary malevolence would imply that human civilization should reduce all of its transmission activities so as to minimize its detectability by alien observers. Likewise, assumed benevolence implies that greater transmissions from Earth would increase the chances of contact. But both of these policies are optimistic about the likelihood of contact with alien life. Perhaps a more pragmatic approach is preliminary neutrality, which would remain consistent with business-as-usual on Earth and would not recommend any significant changes to Earth’s future detectability.

A Lunar Telescope Might Help Us Find Aliens

One way to search for extraterrestrial life is to look for tell-tale signs of biology in the atmospheres of planets orbiting other star systems. Such a “biosignature” that shows the simultaneous presence of oxygen, water vapor, and methane, for example, would be consistent with the presence of surface life on a planet. Observing biosignatures on other planets is a difficult feat, but current and future ground- and space-based telescopes are gradually enabling these observations.

Another place to build a telescope for observing biosignatures is the moon. Stoney Simons and I explore this idea in a recent paper titled “A trip to the moon might constrain the Fermi Paradox,” which is part of the Futures special issue on the Detectability of Future Earth. The moon’s negligible atmosphere makes observations much easier than ground-based astronomy, particularly at the mid-infrared wavelengths needed to detect possible biosignatures.

Searching for biosignatures in the infrared provides a quantitative method of constraining the abundance of life in the galaxy. Likewise, the possibility of observing “technosignatures” in the atmospheres of distant planets could betray the presence of extraterrestrial intelligence. Actually finding any definitive biosignatures or technosignatures will require at least a couple more decades of observing, but we suggest that a lunar observatory should remain an option for contributing to this search.

Is Climate Change Ever Good?

The cumulative effects of human actions over past centuries such as widespread deforestation and the abundant use of fossil fuels has caused changes in the present climate state that would otherwise not have occurred. This trend of an increase in the global average temperature shows no evidence of slowing into the future, which suggests that uncomfortable climate change will persist in the centuries to come. Most of the problematic aspects of climate change involve its negative impact on humans. This includes shifts in farmable regions of the world, destabilization of parts of the world due to fluctuating food prices, changes in flooding and drought patterns, and forced migration due to sea level rise.

A warming planet might pose problems for humans, but how would climate change affect the welfare of other species on Earth? In a recent paper titled “Is climate change morally good from non-anthropocentric perspectives?” and published in Ethics, Policy and Environment, Toby Svoboda and I examine the impact of climate change on non-human organisms. If we temporarily set aside the interests of humans, might it be possible that climate change provides net benefits to other organisms?

The context of this study is the belief by some people in “nonanthropocentrism” or “anti-humanism” as a philosophy. Such beliefs tend to place human interests beneath those of other organisms in Earth’s community of life. If such philosophical positions are accepted at face value, then this might suggest that climate change is in fact a good thing. Climate change might cause the decline of civilization and even a reduction in biodiversity, but it might allow other organisms to flourish as a result. The net effect could be a much more thriving planet, albeit one in which humans are worse off.

This is not to say that we should ignore the effects of climate change on humans. Instead, this analysis demonstrates that nonanthropocentrism and anti-humanism may be in conflict with modern attempts at mitigating climate change. Our analysis therefore challenges adherents of nonanthropocentric ethics to examine the extent to which non-human interests should take priority over the collective interests of human civilization.