Today we are thinking towards the future of human civilisation and our ability, as a species, to play the long game. What are the risks that face our species and how could these risks be mitigated? The term existential risk refers to a hypothetical future event which could either cause humanity’s permanent extinction or seriously hinder the species’ potential. These kind of global risks can be split into two camps; those from which we only have ourselves to blame and those that come from the almighty hand of nature. The former are known as anthropogenic risks and the later non-anthropogenic. Today we’ll cover the non-athropogenic in order to avoid the guilt a little longer.

Extraterrestrial Arrival

For years we have been sending out signals hoping that someone out there will hear our cries. Humanity’s songs have been played out across the universe’s sky and missions have been sent into the depths of space carrying time capsules intending to communicate a story of our world to extraterrestrials. We boldly shout out into the abyss where we are, what we are and that we are currently (as a planet and species) alone.

Although alien life has to this day eluded us, many prominent scientists such as Carl Sagan have hypothesised that the existence of such life in the vast cosmos is very likely. Quoting Sagan, “the universe is a pretty big place. If it’s just us, seems like an awful waste of space.” There are many then that have heavily cautioned against efforts to actively hail extraterrestrial life to our blue planet. Should the life-form who hears us be advanced enough to have mastered interstellar travel in order to able to reach us, they would of course then be far more advanced than humanity and why should we assume them kind to us? They may not empathise with us but instead regard us equally as we disregard inferior animals species. They may simply raid the planet for resources useful them to them and move on as we simply raid natural habitats here on Earth. Stephen Hawking once said “If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans.” Whether we should be a species that prudently batons down the hatches and focus on our own advancement or be a species that naively and optimistically shouts out into the cosmic jungle, is hotly up for debate.

Cosmic Catastrophe 

A few rather big hitters fall into this category. First up is asteroid impact. Asteroids with around a 1km diameter impact the Earth on average once every 500,000 years; this size is unlikely to wipe out the species but, depending on the impact location, may kill on the scale of billions. The annual probability of asteroid impact sufficient to cause extinction has been calculated as less than 1 in 10^8, though whether these estimates can be said to be truly reliable given the timeframe in which humans have been around to able to perform such calculations, is up for debate. Hawking (ever the vigilant) strongly proposed that an asteroid collision should be considered the biggest threat to the planet. Currently no known weapon system exists to shoot down an asteroid that is about to impact Earth and it is said that NASA would require at least five years of preparation time before such an interception mission could be attempted. 

The second risk is from our neighbours in the solar system stepping out of line. Long-term planetary movement is the change in the trajectories of bodies within a solar system, resulting from factors such as the change in mass of the system’s constituents. There is believed to be a 1% chance that Mercury’s orbit could be disrupted by Jupiter’s gravitational pull sometime during the lifetime of the Sun. One particularly terrifying outcome of this is the subsequent collision of Mercury with Earth, which somewhat eclipses the asteroid scenario.. 

The last risk to mention is down to the Sun itself. A dramatic increase in brightness of the Sun, known as a solar flare, if particularly powerful, could scorch the Earth’s surface. This could result in a large scale wipeout of life though, due to the orientation of the Sun to the Earth, likely not cause total extinction. However at the end of the day, and a very long day it will be, it is the Sun moving into its last stage of stellar life (for more detail see Story of the Stars) that will cause the demise of our planet. The expansion of the Sun will be so great that it will engulf the planet and they’ll be no safe retreat in sight. Such an event however, is 5.4 billion years away, so even a species optimist wouldn’t feel an impending need to prepare for this.

Humanity’s best chance to mitigate other existential risk events from the cosmos is to branch off of this one planet. Hawking was a resounding voice for humans to begin the process of permanently settling other planets, his sentiment echoed by SpaceX’s Elon Musk (see Making Humans Interplanetary). The need to colonise other planets and become an interplanetary species is the clearest way to ensure our survival as a species, keeping all our eggs in basket Earth is ultimately, a vulnerable position indeed. 

Pandemic

This final non-anthropogenic existential risk in today’s discussion is one we may all be sick and tired of hearing of – so I’ll keep it short. In our globalised world, with the speed and scale of human movement, increasing populations and living proximity, natural pandemics pose a serious risk to humanity. A common understanding in virology is that naturally evolving pathogens will, as a result of natural selection, reach a limit to their deadliness. This is simply because killing the host, kills the pathogen itself and even the pathogen wants to live. However, high transmission rates, incubation periods and the time required for natural selection to occur may cause a pandemic that is close to existential in its level of risk. 

Nevertheless our level of advancement in the science of immunisation and infection diseases with regards to its full potential, is relatively far higher than that of space travel. It is far easier to take the necessary steps here on Earth than the first steps on a new planet. As the speed of vaccine creation during this pandemic has shown us, we do have the tools to mitigate, and fight, such an existential risk. I should caveat that the cosmic risks presented today, are risks likely to occur on the scale of hundreds of thousands, if not millions of years. The same cannot be said however for risks originating from causes closer to home..

In the next post of this series we will face up to the anthropogenic risks to humanity’s survival. I will cover artificial intelligence, biotechnology, environmental disasters, overpopulation and mass warfare. I’ll then draw some interesting links to the Fermi Paradox, which may give reason to the silence of the cosmos. 

Feature Image via Getty/AdobeBox