Models cannot trump reality

kw: debunking, climate change, disasters

A project named EPOCA, for European Project on OCean Acidification, aims to determine just how much trouble shellfish will be in with increased CO₂ levels, in the range up to 1000 ppm. There are two parts to this question:

1. How much harder will it be for shelled marine creatures to produce calcite and/or aragonite shells?
2. How rapidly, if at all, will those shells dissolve back into ocean water, at various levels of atmospheric CO₂?

It is to be hoped that useful answers to the first question can be answered with the experiments currently being carried out off the shore of Spitzbergen (By the way, I wonder why they aren't also trying it in more tropical waters, which dissolve much less CO₂?). The answer to the second question is already known, and it is, "Not at all, or very slowly." Why do I say this?

The blue line on this chart is of interest here. It represents CO₂ levels, measured by various proxy and semi-direct methods, for the past 450 million years. Note the tiny horizontal segment at lower left. That represents the past several million years, the period since the evolution of C4 photosynthesis, since which time CO₂ levels have been lower than at any period in prior history!

I spent many years happily collecting fossil shells from deposits throughout the geologic series from Cambrian times right through the mid-Pleistocene (550 to 2 million years ago). Let's consider the Triassic, a period during which the CO₂ level was four to five times what it is today. I have a lovely Triassic ammonite shell, with mother-of-pearl colors still evident. I don't know how long it was exposed to carbon-rich ocean waters after the death of the host animal, but it survived unscathed, even un-etched, for all the time since, some 200 million years.

Environmentalists fear that "modern" species will have "forgotten" how to make calcite or aragonite shells from more acidic waters, in the past few million years. The energetics of shell production may have changed, so that they are easier to produce now, but it is not likely that there is a difference in kind between ancient shell-producing chemistry and the modern version, just in intensity. A generation is pretty quick among shellfish. While the oceans may be acidifying at a rapid clip, compared to geologic rates, it is still rather slow compared to the adaption time frame of animals that have one or more generations per year, and plankton that have several generations per month. There is another factor to consider.

Suppose it takes several percent of a creature's energy budget to produce its shell. Further, suppose at some level of ocean acidification that requirement doubles. We must remember that it does so for all shellfish. No species or genus is going to have some kind of broad selective advantage over others. They will all be affected equally. In any species, some individuals will have a little more efficient shell-producing organs than their conspecifics, and this will continue, year after year, generation after generation. Genetic drift is more than sufficient for the species to keep up and continue making shells. I expect the EPOCA experiments to show that all species considered will have widespread ability to cope with acidification at all carbonation levels.

When options narrow to surviving, or not

kw: book reviews, nonfiction, sociology, disasters

I am very thankful that I have not been through any disasters. Maybe I came close a time or two; I do recall almost driving into a tornado a couple decades back. But I've had no experiences frightening enough to make me freeze, or wet myself, or faint, or whatever else it is I might do in, say, a plane crash.

Even in more mildly unsettling events, however, the way different people react can be fascinating. Once we got lost in the woods, my son and I, while walking with two other fathers and their children. The youngsters were all about ten. We'd taken a wrong turn on a path, and succumbed to the "It must be right around the bend" fallacy that keeps you going on instead of going back. I tend to be a natural leader, but once the gentleman who thought he'd been showing us where to go acknowledged he was lost, my son took over. He made the decisions, saying, "Let's try this way" and so forth. We wandered about three hours until, well after dark, we found our way to an open area someone recognized. One of the fathers remarked on how cool my son was, because the other kids couldn't keep themselves from saying things like, "Will we ever get out?". He hadn't really led us out, but the fact that he was leading meant we were kept from getting panicky.

When real disaster looms, as I read in The Unthinkable: Who Survives When Disaster Strikes—And Why by Amanda Ripley, the body count is usually reduced if someone takes the lead. Even an inept leader is better than none, because most people in a disaster spend too much time milling about, trying to figure out what is happening. Once they realize something bad really is happening, they waste more time deciding what to gather to take with them.

Ms Ripley tells us that any shocking and frightening circumstance causes a three-step response: Denial, Deliberation, and the Decisive Moment (when any Action that one may take finally gets taken). Those who shift quickly through the first two steps are those most likely to survive, and often are those who help others to survive. Thus, most air crews have been trained, if an airplane crash-lands, to shout instructions to the passengers and hound them out of the cabin. Since most people go into a kind of passive shock that can last a long time, the no-Mr-nice-guy approach is designed to re-shock them into action, but also to give them something and someone decisive to follow so they don't just stampede.

Time and again the author marvels that in story after story told by survivors, people typically behaved very decently and quietly. Panic is actually rather rare. Sometimes that very decency makes things worse; people may try to defer to one another when they ought to be quickly making their way through the exit. The key word here is "quickly"; it doesn't have anything to do with stampeding an exit and blocking it with smashed bodies.

A key lesson about surviving is Rehearsal. It is one thing to buy those cool wire ladders you can hook to a windowsill of your second-story bedroom. It is quite another to actually use it a time or two. Only if you have done it before, will you be able to smoothly get out of your burning house. Otherwise you're likely to find that you can't figure out how to use it, and you either collapse in mid-thought, or jump out the window and crash to the ground, possibly carrying the ladder that was supposed to carry you (it is amazing what people bring with them; nobody likes to flee empty-handed!).

A large section of the concluding chapter is devoted to Rick Rescorla, the security chief who guided all but five of Morgan Stanley Dean Witter's 3,000 employees out of the WTC on 9/11. He was the only security chief who was able to persuade his company to practice evacuation. Every other company lost substantial numbers. Rehearsal was the key. I am glad my company engages in evacuation drills. Though this site is nearly all 2- and 3-storey office buildings, being trapped by fire on the second or third floor is just as deadly as on the fortieth.

It takes only a few minutes to empty the building where I work, and it usually takes less than two minutes to empty an airplane. Even in the best of circumstances, it takes hours to empty a city. When the city leaders spend a few days dithering, then finally make limp-wristed declarations of imminent disaster, we wind up with a New Orleans that will never be the same (I am of the opinion that it ought to be abandoned, and should never have become a large city in the first place, but that's for another rant).

Some people seem to naturally perform better under stress. All of us can learn to do better. I live in one of the less disaster-prone areas of the U.S., but it is well for me to pre-think what I will do if we get a direct hit by a hurricane; how I might respond to being trapped by rising floodwaters if I am at a low-lying area at the wrong moment (this was particularly relevant when I lived in Houston); or how I'll react when I am awakened by a smoke alarm (yes, I do replace the batteries twice yearly). When I lived in California, my preparations had more to do with earthquakes. Those who think ahead live to think again.

Nature's whack at the Dinosaurs' grandparents

kw: book reviews, nonfiction, geology, paleontology, palaeontology, disasters, extinction

My favorite science authors write about difficult concepts in ways that those with less training can understand, or at least appreciate. Douglas H. Erwin has written a great detective story, with the culprit still not fingered, but whose outline is beginning to emerge from the shadows. Extinction: How Live on Earth Nearly Ended 250 Million Years Ago is about an event even more significant for life on Earth than the Dinosaur-killing asteroid that whopped into the proto-Caribbean some 65 million years ago.

What is the Permian? It isn't just a high school in central Texas, nor only a series of ridges the school is named for. Those ridges are named for a geological period four times as distant in time as the demise of the dinosaurs. In Texas, the Permian reefs are a fantastic source of oil, and oil is the heart of Texas's economy. But the Permian is famous for more than that.

To a geologist, the Permian era lasted from 298 million years ago to just before 250 million years ago (abbreviated "ma" hereafter). It is one of ten major divisions of "deep time", stretching from about 2 ma to about 600 ma. It is very nearly in the middle. One of the later ones, the Cretaceous, ended with the asteriod impact that took out all the larger dinosaurs, leaving us with the little ones, that became the birds. In each of these eras, rocks worldwide contain specific kinds of fossils, and record a suite of ecological conditions that changed rather abruptly from one to the next. At least five of these abrupt changes included a mass extinction, a short interval (a million years or so? or perhaps only a few years...or less?) during which many species vanished and after which new species arose. The great extinction at the end of the Permian era is the most severe.

We know the following: about 90% of marine species, and 75% of land species became extinct. This compares to about 25% marine and 20% land species that died with the dinosaurs in the Cretaceous extinction event. The kinds of rocks being laid down everywhere changed, from massive limestone reefs to thinly layered mudstones and clays. The thin layers are particularly clean because there were no bottom-feeding critters to stir them up or burrow through them...for a few million years. Even for those species that weren't eliminated, only perhaps a percent or two of the individual animals or plants then living survived the catastrophe.

What catastrophe? Another asteroid? Lotsa volcanoes? What?? Dr. Erwin makes it clear he cannot give us a final answer, but he is able to eliminate some possibilities, and outline the most likely few that are able to explain the clues that we have.

The fact is, we have lots of clues. Problem is, they are not sufficient to define exactly what happened or in what order. Finely precise age dating of rocks has yielded an upper limit for how long the disaster took: 160,000 years. Other indications hint that it was probably much, much shorter, but the evidence for that is still being eagerly and energetically gathered. Further, the destruction of land species and marine species occurred at the same time. Thus, we can rule out suspects that operate slowly, such as mega-volcanic eruptions occurring over millions of years. We can also rule out most scenarios in which land species died out because the marine species died; we retain only those in which the marine die-off was so abrupt and so pervasive that the land die-off followed within a very short time.

However, we cannot completely rule out mega-volcanoes, if we can determine that the huge volumes of basalt that were erupted in Siberia at that time were emplaced quickly enough. It is kind of hard: The volume of a small continent was laid atop central Asia. Could that have happened in a matter of a few thousand years? Imagine hundreds of Mt Pinatubo, or thousands of Mt St Helens, going off every year for thousands of years. Actually, the style of eruption was more liquid, like tens of thousands of Kilauea eruptions, every year. It beggars belief.

The author presents all the suspects in Chapter 2, presents and explains all the evidence in several following chapters, then discusses the current understanding in the last two chapters. It is fascinating. He tends to favor what he calls Murder on the Orient Express, in which all the suspects participated in a murder. Scientists are not comfortable with scenarios that include too many players. It smacks of "throw in enough special cases until you have everything covered." But it is unlikely that such a significant event in life's history on Earth could have a single, simplistic cause.

I once favored another asteroid hit, bigger than the dino-killer. There may indeed have been one, though perhaps not any bigger. Dr. Erwin presents Jack Sepkoski's proposition, that some kind of comet or asteroid has clipped Earth about every 26 million years... but he doesn't go into it. The mega-volcanic episodes are much rarer, only every 200-300 million years, perhaps. Should an asteroid have barged in just as the Siberian eruption was well under weigh, it could have provided sufficient extra mayhem to make the effects of the eruptions much deeper and more widespread. If big space rocks are landing on a regular schedule, one is bound to arrive when something else significant is happening. So I also now favor the multi-cause scenario.

The mystery isn't yet solved. There's lots of exciting work to be done. What fun!

New Orleans Bay

kw: disasters, city planning, politics

Two days after Hurricane Katrina hit New Orleans, I wrote an Email to Louisiana Governor Blanco, suggesting that the city be relocated to higher ground, such as that just to the north of Lake Pontchartrain. A couple days later, there was a newspaper article about the way she lambasted Speaker Hastert for making a similar suggestion on the House floor. Oh, well. I didn't really think she'd like the idea.

But I really think the existence of New Orleans as the world's largest below-sea-level city has been the result of the most egregious string of stupid city planning decisions in human history (yes, I do think it is even worse than Venice...by far. We knew more in the early 1900s than the Italians did in the 1400s, about sediment subsidence on deltas. It was just ignored).

In my opinion, that portion of the French Quarter, the Old City, that is above mean high tide, ought to be protected as a historic enclave. The rest ought to be allowed to return to lagoon status, which is what "nature" wants in any case, and sooner or later it shall be so. But the later it happens, the more it will cost the US Taxpayers.