Understanding 'historical science', Ancient forests reconstructed

In the course of catching up on my normal reading, I picked out a couple of pieces to share with you from the Naturalis Historia blog:

Origins Science and Misconceptions of Historical Science

This article offers a brief and practical discussion on the false dichotomy Answers in Genesis places between "origins science" and "operational science"—the latter of which is supposedly characterized by repeatable experimentation. The implications of AiG's dichotomy is that all scientific inquiries into past events are treated as suspect, and the conclusions of such studies become susceptible to arbitrary rejection. Although AiG and other creation ministries devote much to the study of Earth history as they imagine it, they escape the 'limitations' of historical science by claiming access to the words of an eyewitness observer—namely, God himself.

From a philosophical perspective, however, the methodological distinctions between these forms of scientific inquiry are not justified. Both involve repeatable, 'laboratory' experimentation, though in the case of historical inquiries, 'nature' is our laboratory and the trials have already been run. Hypotheses regarding historical (or geological) events are testable so long as new observations and analyses can falsify the prevalent interpretation. The currently accepted age of the Earth (4.54 Ga), for example, is potentially falsifiable by 1) observations that demonstrate a unique origin of Earth relative to the rest of the solar system; 2) geochemical models that better explain how a Rb/Sr isochron built from ~7 dozen meteorite samples could have resulted from a phenomenon other than the passage of 4.54 billion years, and 3) evidence for the non-uniformity of laws governing subatomic particle behavior in the past.

Answers in Genesis faces a hermeneutical problem as well: nowhere does the text of Genesis claim to be an eyewitness account of Earth's beginnings. The highly imaginative language of Genesis 1–11 conveys its message through alternating concrete narrative and highly structured, semi-poetic prose. Earth's beginnings are described through phenomenological language, consistent with ancient views of the structure of the cosmos. As such, the text may communicate much truth about the nature of the cosmos, humanity, and of history itself, but precludes any detailed reconstruction of that history in modern, scientific language.

The literary approach of Answers in Genesis is, therefore, both theologically shallow and hermeneutically naïve. Granted, they may want to defend against my accusation. But one should note: they cannot do so without appealing to the results of historical inquiry, such as linguistic analyses of ancient Hebrew grammar/vocabulary, comparative literature studies of the Ancient Near East, or the textual transmission of the Hebrew Bible. In other words, they must employ a method that their ministry deems suspect to defend the notion that only an 'eyewitness' account of Earth's origins can reliably guide the historical sciences.

Still interested in how scientists study historical phenomena? Not convinced that AiG's dichotomy is in error? I highly recommend that you pursue this discussion by reading the Natural Historian's latest post, which offers a novel and wholly different approach than in my comments above. Moreover, you will find a range of additional resources on the same topic, from personal commentaries to peer-reviewed literature.

An Ancient and Alien Forest Reconstructed: A challenge for young earth creationism – Part I

Follow this link for one of several posts at Naturalis Historia commenting on the implications of a recent paper by Wang et al. (2012, PNAS), in which scientists reconstructed an ancient (Permian) forest that was buried in situ. Rarely do paleontologists get the opportunity to see habitats as they actually existed, since most evidences of ancient plants/animals are washed into sedimentary basins some distance from their 'homes'. However, volcanoes have a way of taking some rather intrusive snapshots (much like the historical Pompeii). The linked blog article provides the full-color figures from the original study, portraying the methodology and results of the forest reconstruction. Whether or not you are interested in the implications of this find for Young-Earth Creationism, the pictures alone are 'just plain cool'. I highly recommend that you take a look!

Squishy bodies, strange seas: the mystery of Burgess Shale-type fossilization explained?

The Proceedings of the National Academy of Sciences recently published a landmark, yet profoundly simple, report offering direct geochemical evidence of a viable mechanism for Burgess Shale-type preservation (Gaines et al., 2012). One example of such well preserved fauna (called Marella) is shown below:

Results of the international team's research, summarized here, suggest that soft-bodied fossils were preserved in the Middle Cambrian by a combination of favorable ocean chemistry and sedimentary 'sealing'. In short, oxygen-poor basins promoted the preservation of organic matter while scant sulfate concentrations inhibited microbial scavengers that thrive on bacterial sulfate reduction. The researchers also discovered thin laminae of lime cement (calcium carbonate) overlying the fossils. These laminae effectively would have 'sealed' the substrate in which the fossils were forming, thereby allowing organic tissues to decay at rates sufficiently low to be imprinted on the muddy layers of deep ocean sediments.

Mystery solved? Or perhaps, in more scientific terms: 'Mystery framed within a plausible hypothesis with replicated empirical support!'

Or so those pesky paleontologists and paleoceanographers would have us believe, according to Brian Thomas of the Institute for Creation Research. Not surprisingly, Mr. Thomas is skeptical of the described mechanism and reaffirms his belief that Burgess Shale-type fossils are instead evidence of "the Genesis Flood [and an] unprecedented scale of violent geologic activity" (read the full article here).

Violent geologic activity? These words don't seem to fit with the fine-grained canvases upon which the soft-bodied aliens of the Cambrian ocean were stamped. Therefore, I should attempt to explain his thought process. Let's begin by asking: 1) Why does Mr. Thomas reject the mechanism offered by Gaines et al.? and 2) What alternate explanation can he offer for these taphonomic anomalies (i.e. cases of exceptional preservation) and associated geochemistry? The answers are as deceptively simple as his interlocutors are profound.

1) Because he can, and thusly he misleads his readers. Mr. Thomas offers no substantive critique.
2) He does not, though he still pretends to.

I do not mean to be crass, but I am often discouraged by the ease with which Mr. Thomas and Young-Earth Creationist authors dismiss the latest research by misrepresenting rather basic geological observations and principles (see below). The tactic is not only dishonest, but leaves millions of readers—who place their trust in these authors—ill-informed and pursuing a false hope. Let's consider how Mr. Thomas approaches the work by Gaines et al. (2012):

"Marine biologists...never [find] fossils in the process of forming...because when a sea creature dies, its carcass is totally recycled within weeks. So, if a creature's soft parts are going to fossilize, it has to happen extremely fast."

Preservation of soft parts requires something wholly different than rapid fossilization. As Gaines et al. noted in an earlier publication (2008, Geology), the chemistry of Burgess Shale-type (BST) fossils indicates that fossilization did not occur rapidly (i.e. through early permineralization, or a replacement of soft tissues with other minerals). Instead, the process of organic degradation had to be slowed significantly. The most recent paper described independent evidence at multiple sites around the globe for this mechanism, confirming the original hypothesis.

Mr. Thomas continues by sarcastically recounting the authors' description of the mechanism by which these fossils were preserved. For example, he speaks of 'the assumed "global ocean" of the time', adding quotes unnecessarily to cast unwarranted doubt. He then asks:

"But did all that really happen? Probably not, since most of those events invoke unexplained phenomena, such as strange ancient sea chemistry and a puzzling absence of bioturbation. Plus, if sealing buried creatures under limestone explains Burgess Shale-type fossils, then similarly preserved fossils should be found beneath the continent-covering limestones all over the globe, and not just in isolated pockets."

The chemistry of the Cambrian ocean is far from unexplained, and I highly doubt Mr. Thomas is familiar with the plethora of research that currently describes our understanding of it. For example, the oxygen content of the Cambrian ocean is fairly well constrained through proxy evidence (chemistry of preserved minerals and organic matter) as well as geochemical modeling. I know partly because I have presented on the topic at geological conferences and contributed some data. Also well documented are evidences for low sulfate concentrations (less than 1/10th of modern values) during the Middle Cambrian. These explanations are neither novel nor unique to the conclusions by Gaines et al. (2012). However, they were not previously associated with BST fossilization.

Oxygen and sulfate concentrations may also be lower in deeper ocean basins restricted from rejuvenating circulation. Why is this important? Because it inhibits organisms from burrowing in the oceanic sediments! Where no oxygen is available, multicellular eukaryotes cannot survive, so their absence here is far from puzzling! Unless, of course, you posit that a global flood was responsible for the deposition of these rocks, in which case it is puzzling that burrowing animals are absent from layers where other animals are abundant.

Lastly, Mr. Thomas strains at credulity when reasoning that BST fossils should be found across the globe under limestone everywhere. As Gaines et al. point out, it is not the simple presence of limestone overlying mudstone that is significant, but the sudden deposition of calcium carbonate mud to seal off microbial scavengers in environments that also contain the aforementioned geochemical conditions. This only describes a tiny percentage of ocean basins in history. But how does the limey cement arrive in the first place?

"The study authors cited evidence of "rapid entombment" by "bottom-flowing density currents." And whereas standard geology has no explanation for such widespread catastrophic undersea density flows, creation scientists can cite the Genesis Flood in describing the unprecedented scale of violent geologic activity implied by these and other fossils."

I am shocked to read that Mr. Thomas believes geology offers no explanation for density currents (which actually occur on a daily basis around the globe, even in terrestrial lake systems!). A simple exercise, which elaborates my surprise, requires nothing more than GoogleMaps. My example (there are thousands more, which you ought to explore) comes from near Lompoc, California:

What looks like a pitchfork, connecting the shallow continental shelf to the deeper oceanic basin, is a network of submarine channels that formed by turbidity currents. Density flows form as a result of subtle differences in temperature, salinity, or suspended sediment load between adjacent water masses (see a fun video demonstration here). These bottom-water currents are capable of transporting calcium carbonate mud from shallow water to deeper basins. And—as Gaines et al. noted—they also provide a convenient trap to preserve soft-bodied fossils under favorable geochemical conditions.

To conclude, I urge you not to be misled by Mr. Thomas' swift, unwarranted dismissal of the latest research in Cambrian fossil preservation. Thusly, a great disservice is done to these fine examples of early life, preserved by an incredibly delicate process. Mr. Thomas' claim that BST fossil beds imply violent geologic activity is flatly wrong. Rapid burial alone cannot explain their preservation, and swift currents—along with the intense weight of overlying sediments—are not likely to leave such squishy bodies intact. Furthermore, Mr. Thomas offers no alternative explanation for the geochemical data reported by Gaines et al. (2012), generally interpreted to reflect Cambrian ocean chemistry and microbial activity.

His credibility is totally lost by saying simply 'No, this can't be right, because then I might be wrong.'

Don't miss the boat!

You may have noticed, things are currently on hold here. In the meantime, I am redirecting you to a guest post I authored, entitled "Don't Miss the Boat!" The (short) article was published recently on The Two Cities blog, which many of you will find a profitable resource on theology, biblical studies, culture, etc. The atmosphere is sufficiently casual to allow for friendly discussion of topics—some quite common, others even controversial—but written by very capable and credentialed, young academics. I encourage you to look around.

Please feel free to share your comments regarding my article (here or there), but do note the following points to avoid some common misconceptions.

1) Despite the subtitle of the article (which was added by the editors), my aim was not to discuss the historicity of Noah's ark. Rather, I am focused on whether the obsession by some over this historical-critical question has unnecessarily divided the church and caused many to miss our real vocation.

2) The points I make do not commit to any particular stance on the historicity of Noah's ark. I do note in passing that there is no geological evidence for a recent global flood, but it is possible to agree with my thesis/discussion while disagreeing about the geological evidence. Obviously, that scientific question is more involved than 800 words can offer. Hence, this blog (among others) is filled with long, detailed discussions on the geological evidence to support my claim.

3) In saying that "the historical question is not primarily A, but B", I am not proposing a simple dichotomy between A and B (hence my use of the term 'primarily'). I understand that the question of the historicity of Gen. 6–9 is still valid and cannot necessarily be divorced from, say, the theological application of this story to redemptive history. My main point is that we should at least agree on how/whether the story speaks to our vocation today before marginalizing ourselves (perhaps unnecessarily) from most of modern society.

Enjoy! Hopefully I will be able to continue my thoughts here in the next week or so.

Team of creationists tackle the "Mysterious Islands" of Charles Darwin (Part 1)

Recently, I came across a documentary produced by Vision Forum, entitled "The Mysterious Islands". I want to share the experience with you—as well as my thoughts—as an example of how Darwinism is depicted and criticized within the Young-Earth Creationist (YEC) movement. The 1 hour and 40 minute video captures numerous conversations, wherein the filmmakers and team scientists discuss animal and rock specimens while retracing Darwin's steps on the Galapagos Islands. This casual style, set in the backdrop of inspirational scenery, should not be overlooked, as it powerfully conveys the communicative purpose of the film to its lay audience: biological evolution has long been disproven, and remains but a philosophical safety net for the unwavering skeptic.

Understanding this mindset is crucial when interacting with the YEC culture, for one soon discovers that 'debating evolution' involves far more than a set of biological facts and hypotheses; rather, it extends to multiple planes of life, from science to ethics to faith and epistemology. Granted, this film does not accurately represent evolutionary theory or its metaphysical implications (in my opinion), but it would be equally naïve to ignore these questions in critical discussion with those skeptical of evolution and/or conventional geology.

Before jumping into that critical discussion, I want emphasize that the cinematography and production of this film was spectacular. The filmmakers (Erwin Brothers) successfully captured the beauty of these islands and their fauna in such a manner that kept me interested. For those of you who have not seen the film, it is currently available on YouTube. My citations below are approximate and refer to times in the YouTube version. Following is Part 1 of my review, which focuses on the geological topics in the film.

Retracing Darwin's steps..."to prove him wrong"

In celebration of the 200th anniversary of Charles Darwin’s birth, Doug Phillips of the Vision Forum led a once-in-a-lifetime excursion to the Galapagos Island. Accompanied by Dr. John Morris of the Institute for Creation Research, a film crew, and his 16-year-old son, Phillips is not shy about his mission. He states at the outset:

“Almost two centuries ago, a man named Charles Darwin ventured here, and the world was never the same.... [We have come here] to test Darwin’s idea’s in light of good science and eternal truth... [Darwin] got some things right, but I’m convinced he got even more things wrong. And the result was a lot of confusion about life, science—pretty much everything.”

Phillips sees the Galapagos Island as a crucial geographic center of what he considers a battle for the worldviews. When asked by the film crew to explain their role in documenting the adventure, Phillips responds that “It is the defining issue at the defining time... We’ve gotta go to ground zero.” (11:25) This film thus rests on a drawn dichotomy between the Bible and young-Earth creationism on the one hand, and evolutionary biology and skepticism on the other.

Geological mishaps

In a ‘tabletalk’ discussion with the crew (~12:00), Phillips introduces and explains the role of Dr. John Morris—current president of the Institute for Creation Research (ICR) and son of the late Henry Morris. Dr. Morris received a Ph.D. in Geological Engineering from the University of Oklahoma, where he briefly served on the faculty. He was thus the ideal companion for Phillips, who explains that “when we came to the Galapagos, we knew that we’d have to handle the geology...”. My curiosity spiked: how will the geology be ‘handled’? Will Dr. Morris propose a mechanism by which these islands could have formed and then eroded into the modern landscape within the past ~4,500 years (i.e. since the Flood)? This would require a detailed look at the petrology of islands, as well as their modern morphology and climate. Will he test published geochronological data, which place the age of the main islands at ~2.4–1.9 Ma? Will he contrast those with K-Ar dates of the most recent volcanic activity (at Volcán Alcedo), which dates to less than 120 k.y.? What about the now submerged, wave-terraced islands that are part of the same archipelago? Radiometric dates place these former islands between 5–9 Ma, inline with estimates based on plate-tectonic motion. With so much to cover, I wasn’t sure what to expect.

Intermediate Fossil Forms

Dr. Morris’ first comments on geology came an hour into the film, during a discussion on intermediate fossil forms. Phillips paraphrases Darwin as saying “We don’t have them now, but we’re going to find them.” He then sarcastically asks John Morris whether he had seen any transitional forms lately in the fossil record. Morris responds (1:01:10) “I’ve been studying a lot about fossils lately. I’m writing a book on fossils. There’s just no transitional forms. There are the same categories that are alive today; these kinds that we see alive today—the dogs and the cats. We see extinct cats and we see extinct dogs, but they’re dogs and cats.”

Such a confusing generalization of the fossil record belies its complexity, however, not least because dogs were domesticated from wolves by humans and do not really appear in the fossil record. Given the modern understanding of rates of evolution and the paucity of geological preservation, paleontologists today recognize that Darwin’s assessments of the fossil record were not only premature (transitional forms have been found), but were predicated by a false understanding of both macroevolution—namely, phyletic gradualism—and genetics. In other words, speciation is rarely accompanied by a gradual shift in phenotypic expression (anatomy, etc.), as demonstrated in modern populations of recently isolated fishes (e.g. African cichlids) and small mammals. When isolated, species can also become very large (Galapagos tortoise) or very small (Pygmy mammoths) very fast.

Thinly bedded sediments and catastrophic flows

The team later took a boat past cliffs of exposed volcanic flows. Dr. Morris took a moment to speak about thinly bedded pyroclastic flows. To my surprise, he explained them as having been laid down one layer after another (in a matter of seconds for each), as though each tiny layer represented a depositional 'event'. Granted, pyroclastic flows are rapidly deposited, but not as individual, millimeter-thin layers. He continues:

“I was taught [as a budding geologist] that whenever you see these fine gradations like this, these are formed—they say—in a lake environment, or maybe a lagoon or something like that. And it’s seasonal deposition. In the winter there’ll be a little bit, less than a millimeter, and in the summer there’ll be a little bit. And whenever you see this layer (a winter/summer couplet), that represents a year. And if you go near this cliff, you’d see millions of these layers...But with a catastrophe, things could happen in a hurry.” 

I was somewhat shocked by this explanation. Any experienced geologist (and this includes Dr. Morris) should be able to recognize the difference between varved lake sediments and a pyroclastic flow. Unfortunately, the audience will come away with the impression that scientists have long interpreted volcanic ash and mud flows as gradually deposited lake sediments. This is simply not the case.

Lake sediments contain abundant organic material (not likely to be found in pyroclastic flows) or fossils (e.g. Green River Formation) within a matrix of sedimentary minerals. Organic carbon can be recovered and analyzed to confirm whether it came from decomposing remains of lake algae, trees, grasses, and/or various aquatic plants. A quick scan on the X-Ray Diffraction machine can tell you whether the minerals are relatively unaltered specimens of feldspar, mica, and glassy quartz that were buried quickly after a volcanic eruption, or highly weathered specimens of the same that accumulated slowly in an open lake system. In the case of lake sediments, further analysis should be able to identify sedimentary calcite, which precipitates in certain lakes during the summer months. The isotopic composition of calcite can be used to distinguish between minerals formed in a lake system fed by rain/snow and broken up pieces of limestone that just happened to ‘get caught in the flow’. In short, abundant methods are available (I have focused on the geochemical) that would prevent any serious geologist from mistaking volcanic flows (including mudflows) from lake sediments. Dr. Morris’ claims here are entirely dishonest.

Radiometric dating

Convinced by Dr. Morris’ discussion on volcanic sediments, Doug Phillips inquires about the age of the rocks. Dr. Morris is ready to respond anecdotally with an example not from the Galapagos Islands, but from Mt. St. Helens, wherein he claims that rocks formed in the recent eruption had been dated radiometrically at 2.4 million years. This claim refers to an old study by Dr. Steven Austin, who prepared the Mt. St. Helens samples for conventional Potassium-Argon (K-Ar) dating. It should be pointed out, however, that only a single biotite phenocryst actually ‘dated’ to ~2 million years old, while other samples yielded much younger dates (most of which were indistinguishable from zero). Dr. Austin sent the samples, moreover, to a laboratory that explicitly stated they lacked the precision to analyze young (<2 m.y.) rocks. The reason is that zero-age volcanic rocks contain very little to no radiogenic argon (i.e. produced by radioactive decay). Modern laboratories that work with such young samples thus require expensive vacuum pumps and a type of ‘amplifier’ for the mass spectrometer, called an electron multiplier. In other words, Dr. Austin’s approach was very similar to trying to measure a few specs of dust on a scale at the grocery store, and then concluding that the scale must be broken because the dust cannot possibly weigh a full ounce! By this reasoning, I am paying far too much for my vegetables.

Unaware of these blunders, Doug Phillips believes that this example raises a fundamental question about radiometric dating. “Every one of those recent volcanoes has been dated at millions and millions of years...”, says Dr. Morris while ignoring current research and propagating his error. Doug asks, “What’s the problem then?” Morris swiftly retorts, “I think the method is wrong! The measurements are precise. The equations, everything is right about it. But the assumptions behind the theory are wrong.”

And cut. The audience is left to imagine what those assumptions might be, which of them might be wrong, and how Dr. Morris can actually verify this. We are not told that 39Ar/40Ar dating of recent volcanoes has actually been used to verify the method’s accuracy. Instead, the audience is kept in the dark about modern geochronology, which has long established various methods by which to test its assumptions.

Uniformitarianism

It is well known that Darwin carried with him to the Galapagos a copy of Charles Lyell’s Principles of Geology. In fact, Darwin is well remembered by some for his contributions to the geology of volcanic islands. According to Dr. Morris, however, this book may as well have been a pair of sunglasses, since “Lyell based his assumptions [that the earth was vastly older than the Bible claimed] on uniformitarianism.” (1:08:35) Of course, Lyell and many of his contemporaries did not believe this age of the Earth was necessarily at odds with the Bible. He simply described methods to interpret geological strata—some of which are still in use today. As the dialogue ensues (1:10:45), however, it becomes apparent that nobody on this trip quite understood the meaning of uniformitarianism:

   Phillips: “Is there a message that the salt gives us?”

   Dr. Morris explains how salt is fluxed to the ocean through continental weathering, and that the ocean’s salt content is building up year by year. Then he says, “If uniformitarian thinking is correct, and the oceans are gaining the same amount of salt every year...with a simple division, you can tell how old the ocean is just by the salt content and the introduction of salt... If the oceans were millions of years old...they would now be so choked with salt, nothing could live in the ocean.”

Dr. Morris thus falsely presents uniformitarianism as a simple extrapolation of modern processes and rates into the unknowable past. In reality, the amount of salt being carried into the ocean is not constant, and neither would we expect it to be constant over geological time. Along Dr. Morris’ line of reasoning, one might similarly predict that my bank account cannot be older than one month, simply by comparing the balance today (I just received my tax return) with the balance last week. One major task of geologists has been to investigate how these geochemical cycles (the calcium and chlorine cycles, for example) have changed over geologic history. Some processes add salt to the ocean; others remove it. The respective rates are not constant, and uniformitarianism does not assume them to be.

Many creationists have argued along with Dr. Morris that the current amount of salt in the oceans places an upper limit on the age of the Earth (<60 million years), but their position is based solely on the poorly documented sodium cycle. Since Livingstone (1963) first proposed a quantitative model of sodium exchange on Earth’s surface, more recent research has elucidated how mid-ocean ridges remove vast quantities of sodium from the ocean (creationist models actually assume that mid-ocean ridges add sodium to the ocean). Also, thanks to extensive mapping by the oil industry (salt is a very important ‘trap’ that captures oil in the subsurface), we can demonstrate that 1) more salt is exposed at the surface today than ever in geologic history; and 2) modern rates of salt deposition are much lower than the average rate over geologic history. Not only is Dr. Morris’ argument based on a false understanding of uniformitarianism, but it derives from false data as well.

Conclusion to Part 1

I mean no disrespect to Dr. Morris, who seems a capable teacher and a man heartily devoted to his work and his family, but the basic errors made with respect to geology are sufficient to question the quality and integrity of the film. No answers were given, moreover, regarding the actual geology of the Galapagos Islands according to a young-Earth paradigm. Even if you agree with Dr. Morris and think that I have been unfair, I hope that you would be curious enough to search for those answers from qualified individuals. Although Dr. Morris does hold a Ph.D., his academic background is in civil and geological engineering. These fields require you to know something about geology, but Dr. Morris' knowledge of the fossil record, radiometric dating, sedimentology, and the application of uniformitarianism are secondary to his degree. Geological engineering is a very different field from igneous petrology or paleontology, for example, and it's somewhat misleading to refer to Dr. Morris as a 'geologist'. Though I thank Dr. Morris and his colleagues for showing us the beauty and mystery of the Galapagos, I pray you would not lose the necessary discernment to examine his claims.

AiG responds to NCSE's involvement with climate-science education

I have no intention of turning this blog into a discussion on climate change, but in light of AiG's recent response to the new campaign goals of the NCSE, several points are worth highlighting. Dr. Elizabeth Mitchell, who authors the News to Note series at AiG, recently characterized NCSE's approach to climate change education as an effort "to squelch even more academic freedom" (original article here). Disputing Eugenie Scott's own position on climate change, Dr. Mitchell writes, "The problem comes down to questions about observational science and academic freedom."

Let's return later to the topic of academic freedom. First, what sort of questions from observational science does Dr. Mitchell envision that would challenge the current paradigm? Dr. Mitchell admits that "climate change is observable," but she goes on to claim that "observations have not matched the magnitude of predictions based on models...[which] predict massive and rapid temperature changes." Unfortunately, Dr. Mitchell provides no direct references to such models, in which case any critical reader should reserve judgment and examine her claim in light of the primary literature.

Current climate models are summarized by the IPCC 2007 report (Section 8.1 and following), which provides references to individual studies. In section 8.3.1, the authors flatly contradict Dr. Mitchell's claim, noting that:

"[Climate] models account for a very large fraction of the global temperature pattern: the correlation coefficient between the simulated and observed spatial patterns of annual mean temperature is typically about 0.98 for individual models. This supports the view that major processes governing surface temperature climatology are represented with a reasonable degree of fidelity by the models." (emphasis added)

Simply put, Dr. Mitchell's claim that "past increases in atmospheric carbon dioxide...have produced only a fraction of the predicted change" is false. For the sake of argument, however, let us entertain the possibility that Dr. Mitchell has access to models not cited by the IPCC—models that project more 'catastrophic changes'. In this case, she would be obligated to cite those models and offer reasonable evidence to reject the currently accepted models, which dominate the peer-reviewed scientific literature. Since she has neglected to cite supporting evidence and instead misrepresented available literature, she is guilty of misleading her readers—many of whom presume that her career experience as an obstetrician qualifies her to critique paradigms in climatology.

So as not to mislead you, I have reposted the IPCC graphic summary of 14 climate models (produced independently by various research groups). I will let you judge whether observed warming (black) constitutes only a fraction of predicted warming (yellow).

FAQ 8.1 Figure 1 from IPCC (2007). Caption reads: "Global mean near-surface temperatures over the 20th century from observations (black) and as obtained from 58 simulations produced by 14 different climate models driven by both natural and human-caused factors that influence climate (yellow). The mean of all these runs is also shown (thick red line)."

When recent additions to atmospheric CO2 are removed from the models, all of them diverge significantly from the warming trend and predict a stability in global temperatures since 1960. These model results are not the final word on climate change, but they do provide significant evidence in support of the current understanding.

Dr. Mitchell continues her critique by addressing paleoclimate data supposedly used to support model projections—namely, ice-core records of the Younger Dryas (YD) event. The YD cold period was first hypothesized from an abrupt shift in post-glacial, European vegetation patterns (specifically, a flower species called Dryas octopetala). Only much later was it identified in oxygen isotope records from the Greenland ice core. The current interpretation of the event as a short-lived cold period, which lasted from ~13–11.5 thousand years ago, has been corroborated by global vegetation records, lake-core isotope and pollen records, marine isotope records, speleothem records, and more.

But what does all this have to do with climate models? According to prevailing interpretations, the YD 'cold snap' had less to do with greenhouse gases and more to do with oceanic circulation (as an aside, the movie The Day After Tomorrow cites an embellished version of this mechanism). Nonetheless, Dr. Mitchell writes:

"The climatology models in use were influenced by uniformitarian interpretations of abrupt temperature-related oxygen isotope changes in ice cores...By misinterpreting the cause of isotope changes, uniformitarian climatologists naturally construct their models for the future on an incomplete understanding of the past."

In actuality, oxygen-isotope data are not used to construct climate models, which instead rely on meteorological and geophysical parameters. Rather, we use past climatic trends to verify the accuracy of these models. The figure above provides one example, where each model was 'asked' to predict 20th-century warming trends in response to atmospheric perturbations. Whether or not we have rightly interpreted ice-core records is simply not relevant to the integrity of climate models, which predict 0.4–3.6°C warming by 2100 AD (depending on future trends in atmospheric CO2).

I would love to have the opportunity to discuss personally the above citation with Dr. Mitchell. It is unfortunate that her misperceptions about paleoclimatology have caused her inadvertently to suppress the academic freedom she ostensibly defends. Academic freedom allows us to examine critically claims made by the scientific community, as well as to challenge interpretations of data via the peer-review process. But as long as relevant data are suppressed through 'strawman' arguments presented by public figures (whether Dr. Mitchell, university administrators, or presidential candidates), investigators (such as yourselves) are forced to draw conclusions from limited, biased datasets. In other words, misrepresenting the current science only inhibits critical thinking and academic freedom.

Creationism, Climate Change, and the NCSE

A recent article from ScienceInsider asks, "Is climate change education the new evolution, threatened in U.S. school districts and state education standards by well-organized interest groups?" The National Center for Science Education believes so and has taken upon themselves the task of making sure that science teachers are sufficiently informed to teach "good climate science". Director Eugenie Scott, who is best known for promoting the teaching of evolution and fighting to quash legislative maneuvers that allow 'creationist' ideas in public schools, justified the new focus by highlighting similarities between skeptics of both evolution and climate change. She also notes that groups challenging current models of climate change are "more numerous and much better funded" than those battling evolution, and she anticipates tougher resistance to the new move.

Dr. Scott is not the first to draw a parallel between these two controversies, and her sentiments are unfortunately true. I noted in a previous post, for example, that although most skeptics of climate change are not creationists, 'climate-change skepticism' is a logical consequence for those who believe that scientists have grossly misinterpreted Earth history. A quick search on any young-Earth ministry site will demonstrate how tight the bond is, despite the fact that none of these organizations employ qualified climatologists (Michael Oard may be a close exception, but his analysis of the Greenland Ice Core belies his comprehension of paleoclimatology).

So how effective will NCSE's campaign be? Individuals and organizations that deal strictly with creationism have one advantage in that creationists are relatively uniform in their ideological premise. It is far more difficult to generalize about what causes people to doubt the scale of anthropogenic climate forcing than to understand why evangelicals struggle with human evolution. I am anxious, therefore, to see how NCSE decides to tackle the issue, and I hope they will be able to avoid divise and pejorative rhetoric like 'denialism'. Long ago, I stopped using NCSE as a resource on science/faith issues, not for any incompetence on their part but rather for their lack of compassion/empathy with creationists (perhaps they have improved since then?). When it comes to controversies such as evolution and climate change, it doesn't take long to clear out the pews so that preaching to the choir is your only option.

Attempt to correlate ancient sediment core to Abraham's journey "dead in the water"

Several weeks ago, Brian Thomas of ICR offered the curious claim that a Dead Sea Sediment Core Confirms Genesis. "According to the Bible, in around 2000 B.C. what is now the Dead Sea used to be a plain that probably served as farmland for people of the nearby debauched city of Sodom," writes Thomas. After the Dead Sea Deep Drilling Project reported evidence that the Dead Sea once completely dried up in the past, Mr. Thomas drew an immediate connection. He continues, "This research demonstrating that the Dead Sea was indeed once a dry region supports the Bible as a trustworthy historical record."

No one can blame Mr. Thomas for his enthusiasm, but we should immediately question why the presumed connection was not reported rather in biblical archaeology news. The Science Magazine report gives one important clue: the sediment layer to which Mr. Thomas is referring was buried 235 meters below the surface and is 120,000 years old—not ~4,000.

Of course, Mr. Thomas and others would object to the dating methods used to construct an age model for the Dead Sea sediments, but several factors make the objection irrelevant. First, for the Dead Sea basin to have dried up (leaving a layer of pebbled beach deposits), the region must have been extremely arid—more so than today. Since lake levels are controlled by the balance between evaporation and precipitation, higher temperatures and lower annual rainfall are required to dry out the deep, elongated basin. Such climatic conditions would have rendered the region inhospitable to large populations, and farming would have been simply out of the question.

Secondly, more than 200 meters of sediment that have accumulated since the lake dried up defy Mr. Thomas's fantastic timeline. These sediments are comprised of alternating organic-rich silts (winter deposition) and evaporites (mostly calcium carbonate). In other words, not the sort of laminae consistently laid down in multiple cycles per year—totaling more than 5 cm thickness per year—in a semi-arid environment. Moreover, isotopic analysis can be used to verify independently that these laminae result from seasonal transitions, contra Mr. Thomas's unspoken, gratuitous assertion that even stratigraphic dating methods are unreliable.

That being said, multiple independent dating methods (radiometric and stratigraphic; i.e. counting of annual layers) are both internally consistent and place the drying event during the last interglacial, which was more arid for the Levant than the current epoch, according to numerous paleoclimatic records. The preponderance of evidence thus supports the conventional investigative methods, as well as current interpretations of the climate history on a local and global scale.

But what about Abraham?

Unfortunately, Mr. Thomas's take on the evidence would seem to cast doubt on the biblical record, if he were correct. I would propose, however, that he has misused the Abrahamic narrative, whose purpose was to exegete Israel's mission among the nations while warning them of immanent judgement should they fall into temptation as Lot. The fate of Lot's wife even foreshadows that of the Israelites who desired that they could return to Egypt despite the exodus promises. It also highlights the faithfulness of the covenant God, who heard the cries of the oppressed in Sodom as he did in Egypt and acted in their behalf. The Pentateuchal parallels are numerous, and sufficient to conclude that the reference to the "Salt Sea" more likely originated as a tangible referent to explain the gravity of Israel's wavering in the faith.

As an aside, one may argue that the narrative of Sodom and Gomorrah is recounted intertextually by Matthew 10 and 18—both in the nature of the apostolic mission and in the parables regarding "lost ones" and "little ones" of Israel. I would go so far as to say that the parable of the 'Rich Young Ruler' (Matt. 19) echoes the predicament of Lot, who was blessed by excess wealth and became a rich man for whom it was extremely difficult to escape the coming destruction ("camel through the eye of a needle"), but with God working through his messengers (the angels of Gen. 19; apostles in Matthew's account) it became possible (Matt. 19:26). I'll leave it to you to judge the merits of my literary analysis. In the meantime, do not fail to miss the scathing moral and cultural critique that follows from Sodom's fate, which should resonate eerily with our own generation:

"Behold, this was the guilt of your sister Sodom: she and her daughters had pride, excess of food, and prosperous ease, but did not aid the poor and needy." Ezekiel 16:49