Notes on Sources

I would be perfectly happy to spend my retirement investigating Oregon’s volcanoes and reading scientific papers about cats, weather, and geology, but there’s this book, Where Cats Come From, to do and it is science writing for the general public.

This means, since I am a new writer, that I should declare my standing to write such a book.

As the eminently quotable G. K. Chesterton would say, I must be egotistical in order to prove I’m sincere.

A little education . . . 

As far as standing in the scientific world, I have and deserve none.  A two-year forestry degree and several undergraduate years studying geology doesn’t even get you to the doorbell.

But I can write, and I do have enough education in geoscience basics to get the gist of the many papers I read while researching my book and these blog posts.

And twenty-five years of helping physicians put complex biophysical and biochemical information into language that is clear enough for the legal record have taught me how important it is to always keep my limits in mind.

Humility is the only suitable way to approach anything as powerful as the scientific method.

My research for the book today is exactly the same sort of effort I made early in that former career, when you couldn’t just google something you didn’t understand and you would quickly lose your job if you asked the doctors too many questions.  Also, there were no spellcheckers.

The only difference now – apart from blessed technology – is that I’m the dictator as well as the transcriptionist.

But the information I put down now is coming from scientists, so I am also a translator.

That’s a better word than reporter, which I prefer not to use because I can’t compete with all the excellent science reporters out there now.  What they do routinely in the high-pressure, fast-paced world of journalism is nothing short of awesome.

I’m just an entertainer on the sidelines, and since I also want to be as accurate as possible, this entails some picking and choosing from a field that is nothing but one long conversation among highly-trained professionals.

As a layperson, my selections can never be as good as theirs, but the writing that follows will be as accurate as possible, as well as interesting (because I’m interested in the topic).

Here’s how I decide what to include or set aside.

A continent-sized elephant

If you have read the post before this one – the one about supereruptions and the Eocene/Oligocene climate transition – you might have noticed a huge and unmentioned elephant in the room.

It was this: Why did Antarctica freeze over so quickly after millions of years of hosting forests and warmth-loving animal life?  (Rose; Smithsonian)

A quote in that post, from Pagani and others, mentioned their suggested solution to the puzzle (a CO2 threshold level), but there are also other possible explanations for the Oi-1 event, as it is called.

Many researchers are trying to work out why Antarctica froze 33.7 Ma (million years ago).  Their supercomputers and huge databanks give them, not simple answers, but an insight into just how complicated this planet’s climate system really is.

So there is intense debate about it. Their papers are often enlightening to a layperson, but the bigger issue is very difficult to describe when the lay writer is doing general writing and needs to keep to a specific point. 

Someone who is reading about volcanoes and the great climate transition on their phone while traveling to work or class doesn’t want to wonder  why it matters, for example, exactly when South America and Antarctica went their separate plate-tectonic ways.

Even though that is enormously important in the debate about the South Pole ice cap.

So the writer skips the whole question rather than confuse the reader. Another good reason I avoided this particular controversy is that it didn’t have anything directly to do with the post topic .

Now, IF you want to accept the idea that Antarctica froze up because a certain CO2 threshold was crossed, and IF you are curious about the iron fertilization theory that was mentioned in the climate post, linking volcanic ashfall into the sea with atmospheric CO2 drops, then maybe . . . but you have just lost your reader.

There are two too many IFs there.

Scientists love IFs; they are part of the logical process and make excellent springboards for discussion.

But most laypeople are not curious about the conversation that is Science.  They, quite understandably, would rather find out something – it doesn’t have to be much – about the results.

For the phone-reading public, a lay writer must tell a results-oriented science story clearly, and as accurately as possible, without speculation or unnecessary side trips.  For the scientists, she must get whatever she gleans from research papers right and use it in the correct context.

Yes, all this is a challenge.

One way around the problem, though not my way at present, is to find a guide.


Carl Sagan was a remarkable cicerone – a guide who gives information about interesting places to tourists.  He was on the inside and had a gift for conveying his wonder at what science had shown him to the rest of us.

Such people are rare.  More frequently, nonspecialist writers try to find a scientist who is willing to act as a guide.

There are a couple of excellent advantages to this approach:

  • The information given is authoritative.
  • Even if the topic is jargon rich, involving advanced math, the writer has a human subject that any lay reader will be interested in.

There are some disadvantages, too.  Chief among these is that the reader may not get the full picture.

Data can often be interpreted in different ways.  A cicerone knows this, and therefore sticks strictly to what has been established beyond doubt.

For instance, an excellent institutional cicerone – the Smithsonian – offers what may be the best brief lay summary of Antarctica’s freeze-up 33.7 Ma.  According to their writer, a:

“. . . circumpolar current formed in the Southern Ocean because of the northward movement of South America. The circumpolar current helped to isolate Antarctica and probably was an important factor in the early development of the South Polar Ice Cap. The cooling of Antarctica in turn meant that cold water began to flow north along the ocean bottoms from high southern latitudes. These changes in ocean circulation brought an end to the long greenhouse climate . . .”

This is the best-established explanation for Oi-1 and it doesn’t go into the other factors, like CO2 levels, orbital factors, etc., that would just complicate the description.

The Smithsonian is much better at this than I ever will be.  Whoever wrote that was probably a scientist as well as a cicerone.

For me, it’s just that some of the most fascinating details are missing.

For instance:

  • That initial freeze-up was not merely a South Pole event.  It involved reorganization of the global climate/ocean system. And, locally, what made much of that ice melt after 400,000 years or so, if Antarctica was thermally isolated?.  (Zachos and others, 2001)
  • Deep-water flow also may have started from the northern high latitudes at around that same time.  (Via and Thomas)
  • And from that time, 33.7 Ma, to the formation of the first ice sheets at the North Pole some 2.5 Ma, Earth was warmer than it is today, even if it was no longer a greenhouse. (Lyle and others)  Why would Antarctica, where the great sheets of frozen water are melting today, get more and more icy in a toasty world like that?

I am not looking for answers here.  The start of Antarctica’s deep freeze and its later development were incredibly complicated and probably can’t be described in a simple way.

I’m just contrasting the science writing you may be used to with mine.

The Smithsonian is expected to explain things, and as noted above, they do it very well.  They have a very good explanation for Oi-1 that reflects the current state of knowledge as clearly and simply as possible.

My way is to follow the scientific conversation more closely.  I look for an explanation, when one is well established, but also at what researchers are doing.

I think it’s okay to leave some ends dangling in this type of writing.


I select papers based on readability (for my sake) and citations (for credibility of the information in the paper).  If they have lots of citations (for example, almost 3,000 for Brown and others), and don’t rely solely on esoteric things like differential equations, I’ll try to work through it even if it is complicated.

If that’s not possible, I don’t mention anything more than that it exists (like Antarctica’s deep freeze 33.7 Ma).

This is how I will always approach difficult topics in these blog posts and in the book.

Some controversial topics are unavoidable – for example, how and when cats were domesticated.  Many others, like trying to identify rare North American small cat fossils from the last 20 million years or so, are optional.

In the climate post, since I didn’t include any other viewpoints of the Antarctic freeze-up, I probably should have cut the suggestion, in that quote by Pagani and others, about a possible link to CO2 levels, but didn’t think of it until now.


I always try to read at least two different papers for information. This is an advantage over the cicerone system in that more views are available.

Reading more than one paper also raises more questions that help me better investigate and understand what’s being discussed.

Of course, when a layperson selects papers, she does it blindly compared to selections done by experts who have a complete background, know the issue well, and are probably well acquainted with many of the individuals involved.

Online papers come with citation numbers, and these do point to papers that scientists themselves consider important.

Another help for the lay writer is that many scientific authors reference researchers who have arrived at different results than theirs.

They do this because the never-ending conversation of Science involves anticipating objections and answering them as you describe your own results.

Every now and then, though, a writer stumbles across some intense clashes.  These don’t always involve dynamite, but they can be distressing.  (See Oppenheimer, section 6.4.1)

Unpleasant as these are, they also help laypeople who want to understand the basic topic.  A fiery argument sheds light by bringing up things that are so well known to scientists (but not to laypeople) that they’re usually taken for granted and not mentioned.

After all, every human being builds an argument out of simple statements, especially if someone is disagreeing with them.  In scientific arguments, if the other side grants such a statement, then there is probably a scientific consensus on it.

For instance, apparently there is a scientific consensus that the iridium layer at the K/T boundary couldn’t have come from a huge volcanic eruption, even though magmas in large igneous provinces are sometimes enriched in iridium.  (Egger and Brückl)

So there probably really was a gigantic impact 65.5 Ma, whether at Chicxulub or somewhere else.

But this brings us to a point where the writer and the cicerone sometimes must part company.

Science and art

While it is very likely that the K/T extinction was associated with the impact of a space object, what actually happened during and after the blast, some 65 million years ago, is not known because such a thing has never happened in historic times, fortunately.

I certainly don’t know anything about it, but in the next post, which will be about a Friday Feline, I am using just one source of the debate about the K/T event to describe its aftermath:  Robertson and others.

There are probably many other ideas about that aftermath, and Robertson and others have not convinced me because they have used both paleontology and bolide physics in their suggestions.

Other scientists use equally good reasoning.

I have chosen to go with their explanation because it is dramatic and it offers an opportunity to present a unique view of an extinction event from the perspective of a survivor that may have also been an ancestor of the modern carnivore this post is about.

You should know that I’ll do this from time to time.  I’m not the Smithsonian.

To show that I’m not really taking sides in a debate but am just using one argument for my own purposes, I will separate the reference from the regular source list, when it isn’t appropriate to indicate it in the text.

I just want to get this on record.  While I always try to convey what I have learned as accurately as possible, I am a writer, not a scientist.

Of course, the source for these occasional dramatic touches will often describe other viewpoints because the methods of Science are very cool.  

Robertson et al. themselves do this.

They mention the basic problem, which is that the pattern of survival on land in the K/T event is unusual, and they describe at least three research teams who have explained it in ways different from their own ideas.

So don’t ever take my word for something – check the reference given at the end of the post and the references it contains. If your experience is anything like mine has been, this investigation will lead you into a new, but ancient, world.

If once we realize all this earth as it is, we shall find ourselves in a land of miracles: we shall discover a new planet at the moment that we discover our own.

— G. K. Chesterton

Our world

All of us call it a good day that’s fairly sunny but not too hot, with big puffy white clouds scattered here and there in the blue sky, some greenery in view, a gentle breeze, and some time to relax and enjoy it all.

That world belongs to all of us.  And whether or not we have trained to study it, we must live on it.

This is why, though there can be earth scientists and earth lovers, there can never be an earth specialist.  In this special sense, the geosciences belong to everybody.

But our planet is so big, its processes so complex, and geologic time so vast that only the imagination and intelligence of geoscientists can really see the big picture.

These experts are our eyes and they help us to understand this world we’re a part of.

I’m just a layperson like everybody else, but I once saw a cat go by, graceful, secretive, and free, and wondered how it evolved.


My background was such that I didn’t mind doing a little research in a science library about it, and the rest has just developed over the last two years.

Now I’m trying to do the impossible – make a coherent story out of science facts.  It’s fun, as long as I don’t expect to be taken very seriously, and I certainly don’t.

I do mind about accuracy, completeness, and telling a full story, and I hope you will get something out of the stories I tell here, as well as entertainment.

But because it’s all based on science, there is always that unspoken ending:

To be continued . . .

Maybe one of you readers will someday continue or even rewrite whatever tale here most interests you.

Thank you for your interest.


IMAGES, in order of appearance:

Feature image, cat and bricks.  Tom Lane.  “Tiger.”  CC BY 2.0. (Treatment by PhotoDirector’s YouCam)

Cheetah.  Elkhiki, “Jeune guepard trottinant.”  CC BY 2.0.


Brown, J. H., Gillooly, J. F., Allen, A. P., Savage, V. M., and West, G. B.  2004.  Toward a metabolic theory of ecology.  Ecology.  85(7):17711789.

Egger, H., and Brückl, E.  2006.  Gigantic volcanic eruptions and climatic change in the early Eocene. International Journal of Earth Science (Geologische Rundschau). 95: 10651070. doi:10.1007/s00531-006-0085-7.

Lyle, M., Barron, J., Bralower, T. J., Huber, M., Olivarez Lyle, A., Ravelo, A. C., Rea, D. K., and Wilson, P. A.  2008. Pacific Ocean and Cenozoic evolution of climate.  Reviews of Geophysics. 46. RG2002, doi:10.1029/2005RG000190.

Oppenheimer, C. 2011.  Eruptions That Shook the World. Cambridge (UK) and New York: Cambridge University Press.

Pagani, M., Zachos, J. C., Freeman, K. H., Tipple, B., and  Bohaty, S.  2005.  Marked Decline in Atmospheric Carbon Dioxide Concentrations during the Paleogene.  Science. 309(5734):600603.

Robertson, D. S., McKenna, M. C., Toon, O. B., Hope, S., Lillegraven, J. A.  2004.  Survival in the first hours of the Cenozoic.  GSA Bulletin.  116, no. 5/6: 760-768.  doi:10.1130/B25402.1.

Rose, K. D.  2006.  The Beginning of the Age of Mammals. Baltimore:  The Johns Hopkins University Press.

Smithsonian National Museum of Natural History.  Geologic Time: The Story of a Changing Earth.  Cretaceous: Shifting continents and greenhouse climates.  Last accessed in the summer of 2015.

Via, R. K., and Thomas, D. J. 2006.  Evolution of Atlantic thermohaline circulation: Early Oligocene onset of deep-water production in the North Atlantic.  Geology.  34(6):441-444.  doi:10.1130/G22545.1.

Zachos, J., Pagani, M., Sloan, L., Thomas, E., and Billups, K. 2001.  Trends, Rhythms, and Aberrations in Global Climate 65 Ma to Present.  Science.  292:686693.


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