Setting perspectives: life on Earth is dying.
A common perspective is to assume that without the risks created by humans, life on Earth would continue indefinitely.
We think of life as continuing forever, just as child feels their eventual death is so far in the future it can be ignored.
It is human nature to ignore our own mortality. As mature adults, we are aware of reality that all of us are during our whole life headed towards our own death, but other than in jest will not declare “I am dying”, until something makes that reality more imminent. We don’t dwell on it because we can’t change it, but it does have some impact on how we spend our lives.
Yet in terms or the limits of life on Earth, most of us are as unaware of the reality as a two your old is of their own mortality. At least I was for most of my life.
I was aware that one day the Sun would grow to a size that would almost engulf the planet, and clearly that would be an end.
But I was totally unaware that all life would become extinct much, much sooner than that, and the amount of life on Earth had had already halved since its peak, as we head to first the extinction of the complex life on Earth such as humans in between 25 and 100 million years, the extinction of all multicellular live within 1 billion years, and eventually, the extinction of even the extremophiles.
This is not considered important enough to explain in school we humans could have around 25 million years before even the last of us can survive no longer, and during that 25 million years live will become increasingly difficult and the amount of will progressively decline.
, although there is also that it would be best if there were less and less of us over time,
Although there is certainly no need to panic yet, we do already need to stop pretending that population of humans can keep growing while the total life on Earth is declining. We need to accept that there will in the long term need to be less and less of us until we can find a new home, and that is no simple task!
I still find this quite like being given the diagnosis that you are dying, but slowly and you could even die of something else first.
The science of this is not really in doubt, especially that the part that life on Earth is already at around half of its previous peak, as explained in this peer-reviewed research paper, but also easily seen from the graph of total life on Earth, that total life 500 million years ago, was double the current level.
Why? This is explained below in ‘A perspective on understanding climate change’.
This graph puts a timeline on all life ending in around 1.5 billion years, and shows the very last complex organisms, probably not cockroaches but tardigrades, lasting almost 750 million years.
If it is just down to nature, humans would not be the last complex organisms to survive as like the dinosaurs the big ones die out first, and reality is most scientific predictions already allow for the fact that species will evolve as conditions change and humans of today would be gone. Future predictions are always a challenge with scope for error, which is increased by the need to allow for evolution. An answer specifically for humans, depends on even more guesses as to the nature of future evolution, and even guesswork on whether anything we call humans would even exist up until conditions change. There are various predictions of the endpoint, but where on the path to that endpoint it becomes ‘curtains’ for humans becomes speculation.
Life ‘as we know it’, even if things do get more challenging, should safely still be able to exist for 25 million years. For humans, a species that has been around for only 300 thousand years, 25 million year is a very long time, and does put us potentially in our infancy, with the ‘death’ event so far in the future we could ignore it, at least for now. I use a human life expectancy of 75 years, which just above the word average for 2020-2021. Mapping onto the life of a human who will live to 75, that makes:
- Humanity, beginning 300,000 years ago and with 25 million years to live:
- equivalent to a 10-month-old.
- All life on Earth, then beginning 3.5 billion years ago, and with 1.5 billion years to go:
- equivalent to a 52-year-old.
- ‘Life as we know it’, including complex vertebrate life, beginning around 480 mya 25 mya left:
- equivalent to a 72-year-old.
- On the span of life continuing to become more complex, from 3,5 billion years ago for around 25 million more years:
- equivalent to a 74 and half year old, with 6 months left to live.
The perspective of the last some seems particularly relevant for to me, as I think of all life culminating with what we have now, and the end of ‘us’ as being the end.
The impact of the ‘finite life on finite world’ perspective.
Population.
When I was a child, I had assumed that the planet was young, and life was still expanding to fill the planet. This view fit with the reality of the human population growing, it is seemed, projected to keep growing forever.
The realisation that the sum total of life is decreasing puts that human population increase in a new light:
The environment and climate change.
Does it seem strange, that CO2 rising now are creating such problems, when much higher CO2 levels back in the time of the dinosaurs were not a problem but a good thing?
To me it doesn’t make sense until understanding the role CO2 and the Sun in determining our climate on Earth. Then a story emerges:
- The Sun doesn’t just remain unchanged for billions of years and then suddenly heat up and expand into a giant but has always been increasing the heat and will continue turning up the heat until it expands into a giant.
- Of course, the Earth had much higher CO2 levels in the distant past, as it needed them because the Sun was cooler!
- Life on Earth can only exist with such low levels as 0.05% now because the Sun gradually sends more and more heat, so on the times scale of millions of years, CO2 levels must get lower and lower, resulting in less and less plant growth until no more plants can survive.
Back in the time of the dinosaurs, the Earth was different. There was more total life because CO2 level were 4x higher, keeping the Earth even warmer despite the cooler Sun, and importantly allowing the engine of life, photosynthesis, to run faster than today. It turns out there is a reason why the descendants of dinosaurs, birds, never evolved to the size dinosaurs did 100 million years ago.
The big difference of perspective with the attitude to the environment, is that while humans are at serious risk of prematurely ending life on Earth, or at least most of it, through either greenhouse or other pollution or nuclear etc… life on Earth is doomed without some species like humans developing enough technology to overcome the course of nature.
Just getting rid of humans or stopping the development of technology is not really an option. While a species with technology might end life on Earth, life on Earth must end without one.
I agree with Elon must on the idea of becoming a multi-planet species, but I question his idea of timeframes and how easy things are to achieve, and whether even if he could do it, a simple outpost of less than one thousandth of the human population surviving on Mars would be real self-driving multi-planet species. Being a true multi-planet species, which real requires bringing other life from Earth with us, is way beyond where we are at right now.
Perspective and Tools, accessories and what makes humans different.
Yes, humans experienced a population explosion following one of the great human achievements: a huge reduction in infant mortality.
But even prior to that population explosion, the human population was gradually but steadily increasing, which should not be possible on finite planet where total life is already past peak biosphere, unless humans were somehow evolving at an unprecedented rate. How was this even possible?
The answer turns out to be societal evolution.
Humans, and human societies, now consist of not just humans, but humans in combination with tools or “accessories”, and these tools or accessories evolve faster than humans, resulting a combination that evolves faster than with any other species.
Intelligence is not unique to humans.
The use of tools is not unique to humans.
It is the relatively small extra step in intelligence that results in humans passing tools on from generation to generation and allowing tools or “accessories” to evolve is the clear difference. Paleolithic humans of 100,000 years ago were far less different from other species than humans of today, despite being genetically almost identical. The difference is our tools that range from our clothes to our homes, to the books and other tools that enable our education.
These tools also create pollution, emissions, and can be weapons that can destroy us, but they also hold the promise of allowing us to enable life to continue beyond the natural rule that life on every plant otherwise comes to an end as the rising heat from the star eventually means no amount of reduction of greenhouse gasses is enough.
Conclusion.
The conclusion is there is a mission for humanity if humanity choses to accept it: develop the tools and technologies to allow the life of Earth to exist beyond the limiations of one finite planet.