At least this article does say that Earth is unlikely to be turned into Venus by humans.
But, it seems to really short-shrift the discussion about why Venus' atmosphere is so different from Earth's, mentioning only that the various theories range from millions to billions of years ago when the greenhouse gas effect "ran away" to create the high temperatures we measure there not.
I would like to see more about those theories, mainly to know what to think about various exoplanet discoveries.
The article talks about Venus "only" being at about 70% if Earth's distance from the Sun. But, that results in Venus getting about twice as much solar energy hitting its atmosphere. That is a big difference to begin with.
And, speaking of the beginning of both planets as they condensed from the gas and dust cloud surrounding the Sun, why would we expect the initial atmospheric compositions to be much different? The article even says something about nitrous oxide and CO2 "which are released by the burning of fossil fuels". But, that is really irrelevant, because there may never have been any "fossil" fuels on Venus, much less a technological civilization to burn them.
The differences seem to be that Venus lost its water to space, or at least into its atmosphere, but did not lose its CO2. In contrast, Earth seems to have had its CO2 removed from its atmosphere and stored in the solid parts of the planet, by life forms. that also oxygenated the atmosphere, largely by removing the carbon into the ground.
So, it seems unlikely that this all happened by some process where Venus was much like Earth, with abundant life that created an atmosphere like Earth's, only to have had massive volcanic eruptions on Venus release CO2 from under ground in sufficient quantity to kick of the greenhouse effect only "millions" of years ago.
It would not surprise me if Venus simply had an initially dense atmosphere that promptly created sufficient greenhouse effect to have always made the planet too hot for liquid water or the hydrocarbon chemicals that are the basis for life on Earth. With twice the solar energy input, Venus would have an "advantage" to go in that direction, compared to Earth.
So, at least for me, what I think is important to learn from Venus about Earth is more about how Earth could have gone from a dense, heavy atmosphere to what we have today, instead of turning out like Venus. Is the 50% less solar energy input the only determinant?
As stated in the article, we as yet have no way of knowing exactly what led to the runaway greenhouse effect that is believed to have occurred on Venus.
"...something seems to have gone drastically wrong in the development of Venus... There is a good chance that "something" is an extreme runaway greenhouse effect, the consequence of an overabundance of atmospheric greenhouse gases."
The article also does not go into detail about why "we" "believe" that a runaway greenhouse effect occurred on Venus, focusing instead on the approximate timeframe and hypothetical causes of this theoretical process.
"The causes of this greenhouse effect on Venus and Earth are different, to be clear. On Venus, the effect was natural and likely the result of excessive volcanism millions or billions of years ago — on Earth, it is the result of humankind's burning of fossil fuels."
Why should we suppose that it is impossible for advanced life, even technologically "advanced" (as we see it) life to have existed on Venus at some point in its past?
For the author to claim outright as a "fact" that the runaway greenhouse effect on Venus is a result of natural causes is unscientific. To be clear, I am not aware of any evidence to suggest that there was advanced life on Venus at any point in its past, but I have also not seen any evidence to the contrary. How would I have?
It is often forgotten (particularly in the modern media landscape) that the true function of science is to help us make the most informed possible speculations (whenever it is necessary) from a practical perspective.
Science also exists as the best known human framework for engaging in the
perpetual practice of raising new questions about the phenomena we encounter in our so-called "observable universe", and their relationship to each other.
In other words, in this brief article, the author was not able to explore the reasons why many in the scientific community presumably speculate that our neighboring planet experienced a runaway greenhouse effect at some point in its history. I would assume that, based on empirical evidence gathered over time, there have been theoretical (e.g. speculative) discussions, simulations, and research papers on the subject which have led many in the scientific community to reach the conclusion that this speculation is the "most likely" (in light of the fact of uncertainty, which is a permanent condition of human existence) to be "true" (although I have not extensively researched this subject).
The author also did not have the space to go at length into detail about the
theoretical causes of the
theoretical runaway greenhouse effect on Venus, but again, I would assume that scientists have their reasons for speculating as they do.
Now, to quote a portion of your own response:
"The differences seem to be that Venus lost its water to space, or at least into its atmosphere, but did not lose its CO2. In contrast, Earth seems to have had its CO2 removed from its atmosphere and stored in the solid parts of the planet,
by life forms. that also oxygenated the atmosphere, largely by removing the carbon into the ground."
This is a very valid point, and it speaks to the heart of the issue at hand. According to theory (which, not to belabor the point, is nothing more and nothing less than scientific speculation aiming, hopefully, in the direction of the truth) extraordinary amounts of the carbon you speak of that was once stored in plants, was eventually turned through the processes of nature into what we call "fossil fuels".
When we recover those fossil fuels from the Earth and burn them for fuel, all that carbon that has been locked away in the Earth for countless generations is released back into our atmosphere in the form of gaseous carbon dioxide.
It would be reductive to say that this alone is the cause of anthropogenic climate change, however, it is an extremely important part of the picture.
Much like the theoretical runaway greenhouse effect on Venus, the greenhouse effect on Earth has a way of compounding itself.
For example, as the Earth continues to warm in part due to the CO2 released by our primitive form of energy generation, one consequence is the melting of permafrost across the arctic regions. As permafrost melts, methane (another greenhouse gas) that has also been trapped in the soil is released into the atmosphere in massive amounts, adding a correlated layer of cause into the constellation of problems that we reduce to the phrase "anthropogenic climate change".
For human beings, what we call a "problem" is essentially a result (specifically a negative consequence) of causes (plural, because nothing is ever the result of one cause) that we don't understand or are simply unable to rectify.
The lesson that we should learn, when it comes to the theoretical runaway greenhouse effect of Venus, is that sometimes problems have a way of creating new causes that lead to worse problems.
Everything is connected, and when we burn fossil fuels for energy, we are not merely releasing excess carbon dioxide into the atmosphere to no affect. We are creating a feedback loop of problems leading to causes leading to problems, and this process has the potential to spiral completely out of our control if it hasn't already.
If Earth ends up like Venus, it will take a long time relative to the individual human lifespan. That doesn't mean we can't or won't see catastrophic impacts resulting from climate change in our lifetimes, especially when you start factoring in related problems like mass migration, economic and geopolitical instability, and the human propensity for war.
Famines, droughts, monster storms, plagues... all of these things lead to a dearth of resources and massive increases to collective stress and tension, which are primary causes of war.
It would take extraordinary leadership to force us to face the most significant problems that challenge us as a society, all of which are connected and just one of which is climate change.
If we don't face these challenges head on, and soon, it will take even more extraordinary leadership to keep humanity from destroying itself entirely. The problems of our time, like the dynamics of the climate of Venus that lead theoretically to the runaway greenhouse effect, have a chance to feed off of each other and run away from us.