Why World Leaders Should Do a Little More Stargazing: What the Fermi Paradox May Suggest About Climate Change

While there is still much ambiguity in current environmental science as to whether global warming is an “existential threat” or just another serious problem, a glance up at the stars may offer world leaders the unhappy answer.

By: Natalie M. Roy, staff member

Even as global awareness of environmental issues rapidly increases, climate change continues to be a challenging issue for international law to address. The difficulty is largely attributable to the inherent unenforceability of collective action in our sovereign nation-state system; however, it is also ascribable to ambiguity in the current science providing an inviting shelter for many to ignore or minimize the problem. Indeed, while scientists generally concur that man-made global warming is real and significant, uncertainty persists as to the rate at which climate change is occurring as well as the anticipated impact on humanity and other lifeforms that share this planet. The issue has accordingly been framed as both an “existential threat,” guaranteeing the extinction of the human race, and, alternatively, as just a serious problem—one that will undeniably have repercussions for human existence (particularly for poorer populations), but not eliminate it. One way this distinction matters is that it frames whether the conversation among world leaders is a normative one, (that is, should we do something about the suffering of those most vulnerable to increased global temperatures at the expense of our economic interests), or an unqualified one (do something or everyone, even the rich and powerful, dies).

While current environmental science may be ill-equipped to resolve that distinction definitively right now, a glance up at the stars may offer the unhappy answer. One physics theory suggests that climate change is not only an existential threat to humanity—it is the deciding existential threat to all advanced life in the universe.

The theory starts with a paradox: if there are approximately 100 billion stars in our galaxy alone, with an estimated ten billion or so “Earth-like” planets capable of supporting liquid water, why have we not seen aliens? Put another way, despite the meaningful probability that at least some advanced life has evolved on viable planets (many of which have been around for billions of years longer than our relatively young one), the observable universe appears utterly dead. Professor Robin Hanson argues that the failure to find any sign of extraterrestrial life given the enormous likelihood of its existence implies that something is wrong. This notion is conceptualized as the “Great Filter,” representing the theory that intelligent life continually meets its end at a certain point before reaching the ability to explore the rest of the galaxy. After all, if you can roll the dice billions of times, over more than thirteen-and-a-half billion years (the estimated age of our galaxy), you would think that at least one civilization would have figured out space travel, especially when you consider how far humanity has progressed in just a short 200 thousand years.

The answer could simply be that abiogenesis (or the original evolution of life from inorganic or inanimate substances) is actually extraordinarily rare, and therefore we are the first. This would explain the lack of advanced life, or indeed, life at all. Or perhaps abiogenesis is quite common throughout our universe, but the step needed to evolve into complex life, like eukaryotes, or to develop the kind of consciousness possessed by humans, is the rarity. If either were the case, then happily the Great Filter is behind us. However, if life is not routinely impeded from evolving into and past single-celled organisms, then more likely the Great Filter is before us.

One seemingly obvious answer to the Great Filter is simple, and alarming—any advanced, energy-intensive civilization will invariably have feedback on its planet. Accordingly, whether we are talking about mankind as we know it, little green men covered in tentacles, or sentient silicon-based rocks, the basic laws of physics suggest that failure to achieve sustainability may be our universal doom. A recent study by physicist Adam Frank expands on this theory by using population biology to mathematically map out four basic pathways an exo-civilization can take, three of which result in die-off or extinction, and one which represents sustainability.

In model A, a population alters its environment so dramatically that approximately 90% of the population is unable to survive, resulting in a “die-off.” While small pockets of the population may live on, the species is no longer able to sustain its former civilization—a popular premise for post-apocalyptic stories. Model B represents sustainability, where the population growth eventually evens off and while the environment is still altered, stable equilibrium is achieved where neither the population nor the planetary temperature continue to rise anymore. Model C, however, mirrors the real-life cautionary tale of Easter Island—a population grows so fast that it reaches the carrying capacity of its environment and collapses completely. Model D begins similarly to model C with rapid population growth, but in this scenario the civilization becomes aware of the issue and decides to shift its resource consumption. However, while model D records a slight blip in global temperature rise in response to the sustainability efforts, it is too late and the population collapses the same as in its predecessor model. The obvious takeaway: a population must timely act to avoid a runaway chain reaction in its planet’s feedback.

Unfortunately, despite the simple physics of population growth and overwhelming evidence that our current practices are unsustainable in the long-term, it remains far too easy for many to ignore seemingly distant and tangibly uncertain consequences. Fair enough. But the next time a world leader is deciding whether to prioritize her country’s short-term concerns or act in humanity’s collective interest, she may do well to ask herself the same famous question Enrico Fermi asked when looking up at the stars—where is everyone?

Natalie M. Roy is a second-year student at Columbia Law School and a Staff member of the Columbia Journal of Transnational Law. Natalie graduated from Colby College in 2016.