Our planet has suffered at least five mass extinctions in its past where 60% to over 90% of all
known species became extinct. In
addition, there were numerous lesser events in which the Earth became a rather
inhospitable place for life. We humans
should take note of this as we slash and burn our way through our environment since
scientists are already designating our era as that of the sixth mass
extinction.
The most recent occurrence dates back about 66 million
years. It carries the official name of
the Cretaceous-Paleogene extinction event.
It is more popularly known as the event that rendered the dinosaurs
extinct, although about 75% of all species were thought to have died off as
well. It is not easy to determine the
causes of such events, but variants on a few themes have become popular. Changes in temperature can disrupt life
cycles in the oceans effecting sea life directly and land life indirectly. Volcanic eruptions are known to disrupt
climate and the environment by spewing dust and chemicals into the air where
they are spread around the globe. If the
amount of material is sufficient, it can also disrupt both sea and land
lifecycles. To ascertain the timing of
extinction events scientists have little more to go on than fossil histories
extracted from sediments.
The Cretaceous-Paleogene event was subject to the usual
analysis tools by the usual geologists, geochemists, paleontologists and
such. In 1978 the focus was on a series
of immense volcanic eruptions that occurred in a region of India known as the Deccan Traps (the word “traps” in
geology is derived from the Scandinavian word “trappa” for stairs, and it
refers to the stair-like hills that define certain regions). Then in 1980 a renowned physicist, Luis Alvarez, entered the party by
claiming that iridium, a rare element, was found deposited around the globe at
about the right time to explain the extinction.
He postulated that a meteor impact was then the most likely explanation
for large amounts of material lifted into the air causing the disruption of
life. His theory was supported ten years
later when the Chicxulub impact crater was found off the coast of Mexico. The contentious back and forth between
supporters of the meteor impact theory and the more conventional volcanic
theory has been referred to as the “dinosaur wars.”
Bianca Bosker provides an interesting narrative of the
history of this scientific conflict in an article in The Atlantic: The Nastiest Feud in Science. Wars, whether
political or scientific, bring out the worst in people, and, occasionally, the
best in people. She details how the superstar
physicist’s theory became too popular to resist and was taken as “scientifically
proven” by most experts.
“Their hypothesis quickly gained
traction, as visions of killer space rocks sparked even the dullest
imaginations. NASA initiated Project
Spacewatch to track—and possibly bomb—any asteroid that might dare to
approach. Carl Sagan warned world leaders that hydrogen bombs could trigger a
catastrophic ‘nuclear winter’ like the one caused by the asteroid’s dust cloud.
Science reporters cheered having a story that united dinosaurs and extraterrestrials and Cold
War fever dreams—it needed only ‘some sex and the involvement of the Royal
Family and the whole world would be paying attention,’ one journalist wrote.
News articles described scientists rallying around Alvarez’s theory in record
time, especially after the so-called impacter camp delivered, in 1991, the
geologic equivalent of DNA evidence: the ‘Crater of Doom,’ a 111-mile-wide
cavity near the Mexican town of Chicxulub, on the Yucatán Peninsula.
Researchers identified it as the spot where the fatal asteroid had punched the
Earth. Textbooks and natural-history museums raced to add updates identifying
the asteroid as the killer.”
If dinosaur extinction generated a war, it seemed to be
soon over. However, Bosker tells us of a
hero, or in this case a heroine, who arose and fought back against nearly
insurmountable odds to at least bring the conflict to a stalemate. Bosker’s heroine is Gerta Keller, a Princeton
paleontologist, whose specialty is studying fossils of small marine life forms. Her interpretation of the fossil data
suggested that the extinction proceeded much too slow to have been generated by
a meteor impact, and that it was consistent with volcanic emissions that took
place on a time scale of tens of thousands to hundreds of thousands of years
and was suggestive of the Deccan Traps as the source. Keller fought a lonely battle for a number of
years in advancing the volcanic theory, gradually gaining collaborators and
adherents and finally seems to have lifted the hypothesis to the point where
both views are getting equal billing as an explanation for the extinction
event.
It may be that we will never know who is right and who is
wrong. The fossil data may be too
inaccurate to determine the answer.
“Yet even specialists from
complementary disciplines like geology and paleontology butted heads over
crucial interpretations: They consistently reached opposing conclusions as to
whether the disappearance of the species was fast (consistent with an
asteroid’s sudden devastation) or slow (reflecting a more gradual cause). In
1997, hoping to reconcile disagreement over the speed of extinction, scientists
organized a blind test in which they distributed fossil samples from the same
site to six researchers. The researchers came back exactly split.”
The science behind the dispute is interesting and knowing
the cause of the extinctions is certainly of value, but the most striking
aspect of Bosker’s narrative is the behavior of the scientists involved. They like to think of themselves as superior to
others as they project an image of being unbiased interpreters of data whose
only goal is the advancement of knowledge.
In reality, as Bosker indicates, they have their biases, their ambitions,
their lust for fame and glory, and they will occasionally stoop to dishonesty
to achieve their goals. In other words,
they are people with the same failings as other human beings.
Consider the arrogance of Alvarez in pushing his theory.
“Ad hominem attacks had by then
long characterized the mass-extinction controversy, which came to be known as
the ‘dinosaur wars.’ Alvarez had set the tone. His numerous scientific
exploits—winning the Nobel Prize in Physics, flying alongside the crew that
bombed Hiroshima, ‘X-raying’ Egypt’s pyramids in search of secret chambers—had
earned him renown far beyond academia, and he had wielded his star power to
mock, malign, and discredit opponents who dared to contradict him. In The New York Times, Alvarez branded
one skeptic ‘not a very good scientist,’ chided dissenters for ‘publishing scientific
nonsense,’ suggested ignoring another scientist’s work because of his ‘general
incompetence,’ and wrote off the entire discipline of paleontology when
specialists protested that the fossil record contradicted his theory. ‘I don’t
like to say bad things about paleontologists, but they’re really not very good
scientists,’ Alvarez told The Times. ‘They’re
more like stamp collectors’.”
And then there was the “unbiased search for knowledge.”
“Scientists who dissented from
the asteroid hypothesis feared for their careers. Dewey McLean, a geologist at
Virginia Tech credited with first proposing the theory of Deccan volcanism,
accused Alvarez of trying to block his promotion to full professor by
bad-mouthing him to university officials. Alvarez denied doing so—while
effectively bad-mouthing McLean to university officials. ‘If the president of
the college had asked me what I thought about Dewey McLean, I’d say he’s a weak
sister,’ Alvarez told The Times.
‘I thought he’d been knocked out of the ball game and had just disappeared,
because nobody invites him to conferences anymore.’ Chuck Officer, another
volcanism proponent, whom Alvarez dismissed as a laughingstock, charged
that Science, a top academic
journal, had become biased. The journal reportedly published 45 pieces
favorable to the impact theory during a 12-year period—but only four on other
hypotheses. (The editor denied any favoritism.)”
“Ground down by acrimony, many
critics of the asteroid hypothesis withdrew—including Officer and McLean, two
of the most outspoken opponents. Lamenting the rancor as ‘embarrassing to
geology,’ Officer announced in 1994 that he would quit mass-extinction
research. Though he did ultimately get promoted, McLean later wrote on his
faculty website that Alvarez’s ‘vicious politics’ had caused him to
develop serious health problems and that, for fear of a relapse, he couldn’t
research Deccan volcanism without ‘the greatest of difficulty.’ ‘I never
recovered physically or psychologically from that ordeal,’ he added. Younger
scientists avoided the topic, fearing that they might jeopardize their careers.
The impact theory solidified, and volcanism was largely abandoned.”
Bosker then describes the environment within which Gerta
Keller had to work as she continued to push the volcanic theory in the face of
the conventional wisdom.
“As Keller has steadily
accumulated evidence to undermine the asteroid hypothesis, the animosity
between her and the impacters has only intensified. Her critics have no qualms
about attacking her in the press: Various scientists told me, on the record,
that they consider her ‘fringe,’ ‘unethical,’ ‘particularly dishonest,’ and ‘a
gadfly.’ Keller, not to be outdone, called one impacter a ‘crybaby,’ another a ‘bully,’
and a third ‘the Trump of science.’ Put them in a room together, and ‘it may be
World War III,’ Andrew Kerr says.”
“Keller aired a long list of
grievances. She said impacters had warned some of her collaborators not to work
with her, even contacting their supervisors in order to pressure them to sever
ties. (Thierry Adatte and Wolfgang Stinnesbeck, who have worked with Keller for
years, confirmed this.) Keller listed numerous research papers whose early
drafts had been rejected, she felt, because pro-impact peer reviewers ‘just
come out and regurgitate their hatred.’ She suspected repeated attempts to deny
her access to valuable samples extracted from the Chicxulub crater, such as in
2002, when the journal Nature reported on accusations that
Jan Smit had seized control of a crucial piece of rock—drilled at great
expense—and purposefully delayed its distribution to other scientists, a claim
Smit called ‘ridiculous.’ (Keller told me the sample went missing and was
eventually found in Smit’s duffel bag; Smit says this is ‘pure fantasy.’)”
Some might find a little back stabbing and deceit related
to an arcane subject entertaining. But
what if the topic was of great significance such as a current health issue? Would you want a similar set of “experts”
weighing in on what could be a matter of life or death? As a practical matter, in such an event there
would be public servants driving the discourse and keeping the participants honest. But for the monitored group of scientists to
be effective in driving public discourse, they must have credibility with the
general public. The “dinosaur wars”
nonsense does nothing to buttress the credibility of science. There is nothing entertaining about it.
On a slightly lighter note, the personal bias of
scientists for their pet theories, as demonstrated here, is not a new
phenomenon. Max Planck, one of the fathers of modern physics, recognized this
long ago and came up with a relevant comment.
When translated from the German it reads like this.
“A new scientific truth does not triumph by convincing its opponents
and making them see the light, but rather because its opponents eventually die,
and a new generation grows up that is familiar with it.”
There seems to be a lot of truth in that statement. It has been quoted many times, usually in
snappier versions. Should one wish to
whip it out in a discussion, the following examples are probably more effective.
“Truth never triumphs—its
opponents just die out.”
“Science advances one funeral at
a time.”
The interested
reader might find the following articles informative:
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