Thanks to multiple billion years of evolution, the human race has now become indomitable in a million ways. Homo Sapiens have stayed on the face of this planet for 200,000 years, having achieved the unique position of altering the planet as we want. We’re ahead of every other species by a huge margin, and our prowess over physics and technology ensures we maintain our lead.
We may be roadblocking evolution for other species simply because of our dominance. But longevity is no guarantee of sustainability. In fact, there’s a solid possibility we may not exist to dominate the planet in the long run. Human extinction is a highly probable scenario, and there are multiple reasons making it a distinct possibility.
Let’s delve into human extinction. Consider two cases – one where 100% of our population has been exterminated, and another one where slightly less – about 99% of the existing humans are off the picture. Many people may quickly point out that the later case isn’t extinction at all – a scenario where 99 percent of Earth’ existing population is erased might not really eradicate the presence of human civilization on the planet. The remaining population could re-populate and, while we may have lost a lot of centuries of progress, we can still get back on track. But that’s not entirely true.
Our chances of survival depend more on how human extinction will be caused, instead of how many it kills. An asteroid strike, for example, is theorised to wipe out every human being on the planet, except maybe those on research stations in Antarctica? But how much of a purpose will that serve, when folks there are stuck without supplies, and getting back to other continents is fatal (courtesy extreme temperatures and lack of transport)?
If we chalk down the probable reasons leading to human extinction, we can categorize them on the level of the potential threat they carry. Let’s start in an ascending order, with the least likely scenario that could cause human extinction.
Human Extinction by Natural Disasters
Natural disasters are never killing us off. Sure, they cause a huge amount of destruction and loss of life, despite all our preventive and predictive technology. But almost all natural disasters are localised, and we’ve spread all over the planet for a disaster to even be a remote threat to humanity.
Volcanic eruptions and earthquakes can be daunting. A volcanic super-eruption (VEI 8) happens on average every 50,000 years. The most recent one erupted at Oruanui in New Zealand around 25,000 years ago. However, over the past billion years, we’ve become an adaptive species to the point that we’d survive even the largest volcanic eruption in the Earth’s history. But it’s important to remember that even though we are adaptable, we are not invincible. While a single supervolcanic eruption might not wipe us out entirely, it could certainly trigger a cascade of events that could lead to human extinction.
Human Extinction by Cosmological Disasters
Phenomenon like solar flares, however intimidating they are, can never never large enough to destroy our entire atmosphere, and thus our species. A supernova explosion in the planet’s proximity might strip the Earth of its ozone layer, allowing penetration of UV rays which in turn, would wipe out most of our population. But parts of Earth will remain habitable, preventing human extinction.
Climate change won’t happen quickly enough to cause human extinction, killing more than a couple billion people in the next two centuries, even at worst. A natural pandemic of the worst kind in Earth’s history would kill, at most, a couple billion people. While climate change may remain a threat, it isn’t likely to wipe off humanity. Other species however, may be pushed to extinction.
Gamma Ray Burts
Similarly, a gamma ray burst aimed directly at Earth would vanquish most of us, but would spare some of those who happen to be underground at the time. But they won’t last long either – a gamma ray burst is going to alter the climate enough to make the planet inhabitable for a long time, potentially leading to human extinction.
Magnetic Field Reversals
The Earth’s magnetic field weakens every few hundred thousand years as it reverses itself. Whether these events correlate with mass extinction events, including human extinction, is up for debate. While some argue that the magnetic weakening allows atmospheric oxygen to escape, killing most of its species, others strongly oppose this hypothesis.
Human Extinction from Global Nuclear War
The idea that global nuclear war could kill most or all of the world’s population, leading to human extinction, has been critically examined. On a series of investigations done by the world’s leading climatologists, the plausibility of the idea was found to range from negligible to significant. A number of possible reasons for beliefs about human extinction are presented, including exaggeration to justify inaction, exaggeration to justify concern, fear of death, exaggeration to stimulate action, white western orientation, the pattern of day-to-day life, and reformist political analysis.
Results of several researches evaluated the long-term environmental consequences of a nuclear war. These involved baseline scenarios fought with barely 1% of the explosive power in the US and/or Russian launch-ready nuclear arsenals. They concluded that the consequences of even a “small” nuclear war would include catastrophic disruptions of global climate and massive destruction of Earth’s protective ozone layer.
These and more recent studies predict that global agriculture would be so negatively affected by such a war, a global famine would result, which would cause up to 2 billion people to starve to death. If future nuclear weapons even more powerful than the ones which exist today are used, it’d probably be enough to wipe out all the support system our planet provides us.
The Earth has been bombarded by asteroids and comets for almost its entire existence, even holding the hypothesis that they delivered significant water reserves. This heavy bombardment may have continued as recently as 3 billion years ago, posing a major obstacle to the very emergence of life. The impact of a large asteroid or comet is yet another reason to contemplate the potential for human extinction. It is estimated that a celestial body exceeding 25km in diameter could entirely wipe out our species.
While Earth is constantly under “fire” from celestial objects, thankfully, most of these are mere dust or sand-sized meteors creating shooting stars. School bus-sized asteroids might hit our planet every few thousand years, medium-sized ones (around 300 meters) every 500 centuries, and extinction-level events only every billion years. So, while the threat exists, the good news is, that it’s a very infrequent one.
A 10-15km asteroid impact in Mexico seems to have been what killed the dinosaurs. The Spaceguard Survey is a measure devised to locate and track as many near-Earth objects as possible. As and when an asteroid is identified, that isn’t on a collision course with Earth, the calculated odds of an impact go down a little bit. If the rock is in a close-earth orbit, we’ll have a good margin of time for advance warning, but a comet might not give us warning time to react or take precautionary measures at all. Quickest human extinction ever.
Human Extinction by ASI
The most hyped technological leap in recent times is artificial intelligence. We’re witnessing exponential growth in computing, and predictions are this will peak with the birth of Artificial Super Intelligence within a couple of decades.
The idea of superintelligence might be fascinating for the most of us but here’s what most of us don’t really grasp: you can broadly categorise intelligence on two parameters – speed, and quality. Take computers for example – they’re incredibly fast, and therefore score on the speed parameter – but they’re stupid. There’s no self-awareness, there are no self-learning algorithms, and thus, they’re low on the quality scale.
Humans beings though, happen to be incredibly slow in terms of speed – we can’t compute nearly as fast as our most basic machines, but we’re endowed with incredibly intelligent algorithms that give birth to consciousness. So we’re high quality.
The goal the computer industry is currently racing to, is to achieve a high-quality, high-speed artificially intelligent computer.
The fear here is that once birthed, artificial intelligence will could exponentially learn at an uncontrollable speed. And then turn on us.
Right now, we’re living in an age where Artificial Narrow Intelligence (ANI) and Artificial General Intelligence (AGI) are becoming increasingly common. There are computers defeating humans at chess, personal assistants that give us information before we need it, and even self-driving cars.
Artificial Superintelligence (ASI) is special – an ASI system can learn and grow on its own. Ray Kurzweil expects ASI will arrive on the planet between 2035 to 2060. It isn’t necessarily a pleasant scenario, though. Some fear, perhaps rightly, that ASI could be utilized by irresponsible humans, say a group of terrorists or rogue governments, to disrupt human civilization, potentially leading to human extinction.
If not that, the superintelligent machines might ‘go rogue’ themselves – tracing a path of their own, causing uncontrollable damage and human extinction. However, with controlled growth of Artificial Intelligence, we might even reach a point where machines prompt humans to compete with their thinking ability. If channelized in an appropriate method, humans might evolve to become more capable in terms of intelligence. This may be the most important race in human history. The probability that we are heading towards a blissful era or straight to the gallows still hangs in the balance.
Eminent Australian scientist Professor Frank Fenner, who helped to wipe out smallpox, predicts humans will probably be extinct within 100 years because of overpopulation, environmental destruction and climate change. It is important to note here his mention of the multiple factors that may lead human extinction.