Humble Executive. Literary Artist. Altruistic Libertarian.
Just finished your book and I really enjoyed it. You touch upon many important topics that triggered several responses. Perhaps most important, you succeeded in raising my level of awareness concerning risks to humanity arising from our impact on the earth. You provided a confidant and positive perspective related to these risks, without avoiding the urgency and severity of the situation. A nice balancing act, sure.
Prior to beginning your book, my foremost question was how you could generate enough understanding and consensus related to such complex issues to do anything constructive to change things enough to make the necessary difference in the world. Your book did a nice job demonstrating that examples already exist where the earth is healing from previous damage, the ozone for instance. This also brought to mind two personal experiences in support of potential change: one, while growing up in Southern California in the late sixtes, driving to LA from San Diego and gazing above the LA basin so polluted it looked like we were descending into a bowl of soup. Air quality has improved significantly since that time. Also, San Diego Bay was an ecological disaster in the sixties until clean up efforts made the place half decent again.
You also make a good case for longer range thinking than most of us engage in. For example, my principle concerns are more immediate, and involve how humans routinely treat each other. Unlike your field, where science can bring clear facts and analysis to bear, and at least the possibility of widespread consensus and action, it’s far less likely in my world of concern that any consensus will be reached in the philosophical/political/theological/social/cultural realm that will impel people from visiting violence, death and destruction on such a wide scale as we see today. While your book provides a studied optimistic outlook that may lead to effectively curbing global warming, or even deflecting an errant asteroid, I remain exceedingly pessimistic about the day-to-day state of humanity.
But enough about my concerns. You write on page 283:
…because we must assume our planet is typical.
But Earth is hardly typical based on our limited examples. For example, you write on p. 48:
So far we have not found another planet with plate tectonics.
You pose a key question on the next page:
If size is key, why did a planet so similar in size to Earth evolve in such a different way, absent the global tectonic system that seems key to the character of the planet?
And then this on page 50:
The fact that we don’t really understand the Earth-Venus difference in tectonic evolution soon that we can’t yet predict whether a given planet will have plate tectonics. This is currently one of the greatest weaknesses in our ability to predict which planets elsewhere in the universe are good candidates for life.
Finally, on page 77:
…Earth became something completely different [from Mars or Venus]: a biosphere, a living world. Yet when did this divergence happen?
I believe you already assembled the clues for a possible answer for the source of that divergence. But first, consider a quote from our previous correspondence:
In the late seventies I developed a particular “rare earth” notion based on a cataclysmic collision that occurred with Earth and another large object, resulting in the creation of our moon. (It was very gratifying to see you present this notion as generally accepted within the scientific community, vindicating an idea that my family has derided now for decades).
This same collision, or perhaps some other singular event, may have damaged Earth’s crust, resulting in moving plates and ocean basins. The moving plates drive high levels of volcanism on the planet, and the high level of volcanism is in part, if I understand correctly, responsible for releasing from Earth’s interior the various elements that make up Earth’s oceans and atmosphere.
This insight came about by comparing Mars and Earth, and noting that Mons Olympus is so tall because it sits unmoving over a hot spot on the surface of Mars, a planet without moving plates (and with no oceans and very little atmosphere). Hawaii, on the other hand, demonstrates what happens when a plate passes over a hotspot—you get the creation of one volcano after another, but none of them excessively tall. Neither Mars nor Venus, the two planets most comparable to Earth, are tectonically active, and this may imply an element of geological uniqueness to Earth.
- Earth and moon made of the same stuff
- no solid core in moon, far less dense than Earth
- Earth/Moon unique in solar system, more of a two-planet system than planet/moon
Your striking comment on p. 13 seems to give credence to this hypothesis:
“The outer skin of our planet is broken up into about a dozen rigid pieces: the plates, the shifting shards of a broken sphere."
You provide another piece of evidence on page 86:
…rocks in Australia that are much older…, dating to 4.5 billion years, back almost to the origin of Earth itself, a time when, we thought, there were no rocks, just a hellish sea of molten magma.
Has this notion already been considered and rejected? If so, I’d love to see the argument. If not, is there a way to explore the possibility? If this hypothesis were to be accepted, there are at least two important implications:
1 - a possible answer to the Fermi paradox (complex life is far rarer that previously assumed - more on that below - and intelligent extraterrestrial life nearly non-existent)
2 - a rare Earth makes your topic even more relevant, making this planet that much more precious.
We don’t know how life originated, but let’s say for the sake of argument that life routinely arises on rocky planets like you suggest on page 76:
Comparative planetology seems to be telling us that the conditions needed for the origin of life might be the norm for rocky worlds. One real possibility is that Mars and/or Venus also had an origin of life , but that life did not stick, couldn’t persist, on either of these worlds.
“Simple” life (bacteria-like) may be ubiquitous, whereas “Complex” life (say what arose during the Cambrian explosion) may require very specific elements: plate tectonics, oceans, active volcanism, a large moon, ozone, and myriad other elements that provide the stability and cycles (CO2, for instance) necessary for the development of complex life-forms. These are all elements unique to a ‘Rare” Earth.
The was another improbable evolutionary path. You write on page 433:
The earliest-known appearance of bipedalism, about 6 million years ago, came during a time when Earth entered an extended period of climate change.
This was a major turning point that led to modern humans, a path that other apes didn’t take. As for the uniqueness of homo, consider the Aquatic Ape theory. Largely dismissed by mainstream science, I believe the argument compelling. While Alister Hardy originally proposed the theory, I came across it via Elaine Morgan. If this theory is correct, it means that apes started down the aquatic path, but unlike whales, seals and other aquatic mammals, something stopped the development in that direction and turned them back to dry land. So a double turning may have been required to put homo on the path to sapiens.
I wrote a fictional account of the evolutionary double move of homo, utilizing my literary cosmology as the background:
On another subject, you write on page 420:
Is it all the fault of the CEO of ExxonMobil? No. Most of us drive cars, most of us vote. So blame is distributed…
I don’t believe blame for our killing highways is distributed. I think there is a clear root cause, the violation of a particular philosophical principle. Although the analysis in the following link (The Deadly Highways: why do we accept such senseless slaughter?) is focused more on the immediate harm of our destructive transportation system, the same analysis pertains to longer term issues, such as CO2 emissions.
On a personal note, I had the privilege of corresponding with Lynn Margulis just before she passed. For some reason, I sent her a letter containing my criticism of the state of evolutionary science, and she was very receptive. In return, she sent me a package consisting of two books, a few articles, and a hand-written letter. After writing her back, I received a call from the University informing me that she wouldn’t be answering my letter. A genuine shame, and I envy your relationship with her and Carl and a host of others. By the way, you don’t need to apologize for your privileged opportunities as you sometimes do in this book: the only shame is not taking full advantage of your circumstances (that actually goes for all of us) and you clearly have taken full advantage. But I can still envy.
Anyway, thanks for alerting me to your book, providing the opportunity for such a rewarding intellectual experience.
Take care, and all the best in caring for our collective future.
A review of David Grinspoon's Earth in Human Hands