Graphite Creek Mining Project Will Produce High-Grade Coated Spherical Graphite from the Seward Peninsula of Alaska: Graphite Demand, Geopolitics, and Other Interesting Facts about Graphite

 

 

Graphite One’s Graphite Creek High-Grade Graphite Deposit

     Vancouver, Canada-based company Graphite One is developing one of the world’s largest high-grade graphite mining projects on the Seward Peninsula in Alaska. This project is expected to jump-start U.S. domestic production, processing, and manufacturing of graphite, mainly for anodes of EV batteries, described by the company as follows: “The Project is proposed as a vertically integrated enterprise to mine, process and manufacture anode materials primarily for the lithium‐ion electric vehicle battery market.” The plan is to process the graphite at a facility adjacent to the mine, then to ship the processed product to a battery anode manufacturing facility to be built in Washington state. The company plans to make a production decision based on the feasibility study it began in 2022. The feasibility included an expanded drilling program to test ore quality with results indicating the presence of high-grade coated spherical graphite. Another goal of the company is to develop a complete U.S. based supply chain to facilitate battery anode production. The U.S. is currently 100% dependent on imports for graphite, so this would be a first for domestic graphite. Currently, China supplies on third of U.S. graphite. The drilling program was very successful: “The results – 52 graphite intercepts over 52 holes – confirm our confidence that Graphite Creek is truly a generational resource of strategic value to the United States…” In July, Graphite One was awarded a Defense Production Act grant potentially totaling $75 million.

 

Source: Wikipedia

   

Source: Graphite One

In 2020, the U.S. imported 41,000 tons of graphite. The IEA forecasted a 25-fold increase in global demand by 2040. Graphite One has bold plans to supply the U.S. with graphite: “…to build out a vertically-integrated U.S. based supply chain capable of delivering 41,850 tonnes of battery-grade CSG, and 13,500 tonnes of additional advanced graphite materials annually.” Thus, it appears that Graphite One’s goal is to supply the U.S. with most or all of its mined graphite.

 

Graphite Creek Geology

     According to the USGS, Graphite Creek is the largest flake graphite deposit in the U.S. and one of the largest in the world. Graphite One identified a 16-kilometer geophysical anomaly and the 2023 exploratory drilling confirmed and increased their resource estimates. USGS describes Graphite Creek as an unusual fake graphite deposit. Middle Cretaceous gneiss domes host the deposits. As in many metamorphic rock areas, the deposit occurs near a suture zone where micro-continents collided, in this case during an earlier Jurassic-aged ocean-closing event where an island arc system overrode a passive continental margin.

 

Source: Insights into the metamorphic history and origin of flake graphite mineralization at the Graphite Creek graphite deposit, Seward Peninsula, Alaska, USA. February 27, 2023. Mineralium Deposita. volume 58, pages939–962 (2023). Insights into the metamorphic history and origin of flake graphite mineralization at the Graphite Creek graphite deposit, Seward Peninsula, Alaska, USA | Mineralium Deposita (springer.com)

The report is very detailed, complex, and not easy to understand, even by a geologist with some knowledge of metamorphism. The researchers put fourth four different possible scenarios for the origins of the deposit, as follows: “Current models of crystalline graphite deposits allow for multiple scenarios to potentially explain aspects of high-grade flake graphite enrichment at Graphite Creek. Incorporation of garnet porphyroblasts within the massive graphite lenses and foliation of semi-massive graphite together with peak graphite temperatures of at least 640 °C suggest that lens development took place during syn- to late-peak metamorphism (Fig. 11). This metamorphism happened between ca. 96 and 92 Ma based on the monazite and titanite data from this study (Fig. 6) and Amato et al. (1994). All scenarios therefore invoke graphite concentration via high-temperature metamorphic processes. Scenario 1 is simple in situ metamorphism of carbonaceous shale. Scenario 2 involves devolatilization of calcareous rocks to remove CO2 and form Ca-silicate mineral assemblages such as plagioclase, pyroxene, and scapolite. Scenario 3 involves addition of carbon to the rock via hydrothermal fluids, such as for lump and chip vein deposits. Scenario 4 is removal of silicate minerals from carbonaceous shale by anatexis.”

  

Source: Insights into the metamorphic history and origin of flake graphite mineralization at the Graphite Creek graphite deposit, Seward Peninsula, Alaska, USA. February 27, 2023. Mineralium Deposita. volume 58, pages939–962 (2023). Insights into the metamorphic history and origin of flake graphite mineralization at the Graphite Creek graphite deposit, Seward Peninsula, Alaska, USA | Mineralium Deposita (springer.com)

The paper’s conclusions offer a little more in terms of a basic explanation that I, as a geologist, can better understand:

“The unique flake graphite deposit at Graphite Creek, Alaska, formed due to a combination of factors. Permissive depositional environments for a suitable protolith are biologically productive, restricted, settings. Permissive post-depositional tectonic environments to produce this type of flake graphite mineralization are characterized by high-temperature metamorphism associated with exhumation. Thick intervals of favorable, fine-grained carbonaceous shale protoliths were subjected to at least one episode of high-temperature metamorphism and anatectic melting associated with pluton emplacement, regional extension, and tectonic exhumation on the Seward Peninsula. Strain partitioning and shearing in the northern Kigluaik Mountains, represented by compressed isograds, likely provided conduits for fluid/melt flow and facilitated anatexis, melt loss, and graphite enrichment.”

They note that anatexis has previously only been scarcely associated with flake graphite deposits, so this merits further investigation. Anatexis refers to the partial melting of rock, which may have led to further graphite enrichment. As noted, graphite is a product of carbon-rich rocks being subjected to high-temperature metamorphism. With higher pressures, the end product would be diamond, which occurs rarely in nature. Below is a theoretical phase diagram.

 Source: Wikipedia

 

Natural Graphite Properties, Uses, and Demand

     Graphite is a crystalline stable form of carbon. It consists of stacked layers of graphene that have a hexagonal crystal structure. It is used in pencils, as a lubricant, as an electrode, and in many other applications. Natural graphite occurs in crystalline form as small flakes in plate-like particles. Amorphous graphite is a form with smaller flakes. Lump graphite occurs as mineral veins filling fractures as a needle-like fibrous crystals. Graphite occurs in metamorphic rocks (such as gneiss) subjected to high temperatures and pressures. A theoretically predicted phase diagram for stable carbon is shown below. Higher pressures are required for diamond to form. Graphite properties include a high degree of anisotropy (directional property variations), high thermal stability, thermal conductivity, and electrical conductivity.

 

The layers of graphite are called graphenes. According to Wikipedia: “The two forms of graphite are called alpha (hexagonal) and beta (rhombohedral). Their properties are very similar. They differ in terms of the stacking of the graphene layers: stacking in alpha graphite is ABA, as opposed to ABC stacking in energetically less stable and less common beta graphite. The alpha form can be converted to the beta form through mechanical treatment and the beta form reverts to the alpha form when it is heated above 1300 °C.”

Source: Wikipedia

     Research and Markets describe graphite, its uses, and demand as follows: “Graphite is found in the form of black crystal flakes and masses. Important properties include high electrical conductivity, thermal stability, and slipperiness, i.e., also known as lubricity. These properties make it highly suitable for several industrial applications, including lubricants, steelmaking, refractories, electronics, and lubricants. The use of graphite in emerging applications such as fuel cells and light-weight high-strength composite applications is predicted to surge drive the demand for graphite in the forecast period. The growing adoption of EVs further fuels market growth during the forecast period.”

“China, India, and Brazil are the top three major graphite producers in the world. During the forecast period, the steel industry is the major end-user of the global graphite market.”

Spherical graphite is an intermediate product between natural graphite and fully processed graphite. Further processing to battery-grade is needed. Batteries are expected to remain the fastest growing market segment for graphite. Demand for synthetic graphite is expected to remain strong in addition to natural graphite.

Natural Graphite vs. Synthetic Graphite

     In addition to mined graphite, graphite can also be produced synthetically from a variety of carbon feedstocks including natural gas, petroleum, petroleum coke, coal, biomass, and even used tires. Synthetic production has also been explored as a byproduct of captured CO2 as a method of carbon utilization, with one company currently producing carbon black, from which graphite can be made. Carbon black is used in the manufacture of tires and the process can be reversed so that the carbon black can be recovered from used up tires and be made into synthetic graphite for battery anodes. A Chilean company is seeking to do just that as part of a circular economy approach. Synthetic graphite can be made purer than natural graphite. It is used in specific industries. Natural graphite must be processed to improve quality and purity. This processing includes milling, flotation, purification, and micronization, allowing for removing impurities and adjusting particle size and distribution. An article from Investing News Network summarizes the differences between synthetic and natural graphite:

“Synthetic graphite is purer in terms of carbon content and tends to behave more predictably, which is why it has found a niche in solar energy storage and electric arc furnaces. Synthetic graphite can be significantly more expensive to produce than natural graphite, as the process is fairly energy intensive. In fact, the cost can be double or triple the standard price for natural graphite.”

“Restrictively high prices and specific use cases for synthetic graphite mean that it doesn’t often compete with natural graphite.”

Highly ordered pyrolytic graphite is a synthetic graphite with a highly ordered crystal structure. It is used in x-ray optics and scanning probe microscopy. Electrodes for electric-arc furnaces that melt steel and iron are made primarily from synthetic graphite using petroleum coke as a feedstock. Graphite blocks for energy storage are made from synthetic graphite using a slightly different form of petroleum coke than that used for electric-arc furnaces. Primary synthetic graphite is a graphite powder that is expensive to produce. It is used for high-end lithium batteries. Secondary synthetic graphite is a byproduct that occurs as a powder and can be competitive with natural graphite in some uses, such as brake linings and lubricants. The global synthetic graphite market was at $2.37 billion in 2022 and is forecasted to grow to $3.93 billion in 2031. Thus, it appears that synthetic graphite makes up about one third of the global graphite market with natural graphite making up two-thirds. A handful of major companies dominate synthetic graphite production.

 

Carbon Nanomaterials (made from graphite or from captured carbon)    

     Carbon nanomaterials are produced from graphite and other carbon sources. Sigma Aldritch notes: “Carbon nanomaterials are an extensive family of carbon allotropes, consisting of 0-dimensional fullerenes and quantum dots, 1-dimensional carbon nanotubes (CNTs), 2-dimensional graphene, and 3-dimensional nanodiamonds and nanohorns. Carbon nanomaterials are used in a broad range of applications due to their unique physical and chemical properties.” Some materials researchers think that with manufacturing investment these materials can one day compete favorably with metals and be able to replace metals in many applications. They are lighter than metals so that can boost the energy efficiency of some of the products they would be used for. They have also been proposed as a possible replacement for plastics. Carbon nanotubes share many of the features of polymer plastics. The hurdle in both cases, replacing metals or plastics, is cost. Rice University carbon materials expert Matteo Pasquali noted in 2021: “We can make nanotube fibers and composites that outperform metals, but we need to scale manufacturing processes efficiently so that these materials can compete with metals on price. The key, he notes, is to make carbon nanomaterials plentiful. Polymer plastics and carbon nanomaterials both fix carbon. Pasquali also notes that the rapid development of the plastics industry over a few decades was partially the result of the high availability of light hydrocarbons that were byproducts of refining. In a similar way, if we can improve the economics considerably, we can use captured carbon as a feedstock for a carbon nanomaterials revolution, he suggests. As mentioned above, there is a company making carbon black from carbon captured from making hydrogen through methane pyrolysis. That company is Monolith Materials, and their project is in Nebraska. It is an example of carbon utilization.  

 

China’s Graphite Export Restrictions

     On October 20, 2023, China made the following announcement restricting the export of certain grades of graphite. This is thought to be a tit-for-tat response to the U.S. restricting the sale of certain computer chips to China:

BEIJING, Oct. 20 (Xinhua) -- The Chinese government announced on Friday that it will impose export controls on certain graphite materials and related products.

In an announcement jointly issued by the Ministry of Commerce and the General Administration of Customs, the export of artificial graphite materials and related products with high purity (purity>99.9%), high strength (flexural strength>30Mpa) and high density (density>1.73g/cubic centimeter) will be banned, unless permission is granted.

Meanwhile, natural flake graphite and its products, including spheroidized graphite and expanded graphite, will also be banned from export unless there is permission, according to the announcement.

The control measures take effect on Dec. 1, 2023, according to the announcement.

As the following graph shows, China dominates graphite production. It also dominates graphite processing.

Source: Statista

 

References:

Graphite Creek Project, Alaska. Mining Technology. March 26, 2017. Graphite Creek Project, Alaska - Mining Technology (mining-technology.com)

Graphite One Completes Extensive Drilling Campaign at Graphite Creek, Reports Wide Intercepts of High-Grade Graphite. PR Newswire. October 23, 2023. Graphite One Completes Extensive 2023 Drilling Campaign at Graphite Creek, Reports Wide Intercepts of High-Grade Graphite (yahoo.com)

China announces export control on certain graphite materials, products. Source: Xinhua Editor: huaxia. October 20, 2023. China announces export control on certain graphite materials, products-Xinhua (news.cn)

China's new limit on battery metals could haunt the global EV boom. Jael Holzman. Axios. October 23, 2023. China moves to limit exports of key metal used in electric vehicle production (axios.com)

Graphite One Enters into Market-Making Services Agreement. Graphite One. November 1, 2023. Graphite One Enters into Market-Making Services Agreement - Graphite One (graphiteoneinc.com)

Graphite Outlook 2022: Demand from Battery Segment to Remain High. Priscila Barrera. Investing News Network. January 17, 2022. Graphite Outlook 2022: Demand from Battery Segment to Remain High (investingnews.com)

Electric vehicle batteries may have a new source material – used tires. Li Cohen. CBS News. November 28, 2023. Electric vehicle batteries may have a new source material – used tires - CBS News

Forecast for Natural Graphite Demand is Bullish. Tanka Engineers. April 4, 2021. Forecast for Natural Graphite demand is Bullish (tankaengineers.in)

Global Graphite Market - Forecasts from 2022 to 2027. August 2022. Knowledge Sourcing Intelligence LLP. Research and Markets. Global Graphite Market - Forecasts from 2022 to 2027 (researchandmarkets.com)

What is Synthetic Graphite? Melissa Pistilli. Investing News Network. November 6, 2023. What is Synthetic Graphite? (investingnews.com)

Graphite. Wikipedia. Graphite - Wikipedia

A U.S. Based Supply Chain Solution to Support the Renewable Energy Transition. Graphite One. Surging Graphite Demand - Graphite One (graphiteoneinc.com)

New U.S. Government Report Identifies Graphite One’s Graphite Creek Deposit “is Among the Largest in the World.” Graphite One. New U.S. Government Report Identifies Graphite One’s Graphite Creek Deposit “is Among the Largest in the World.” - Graphite One (graphiteoneinc.com)

Insights into the metamorphic history and origin of flake graphite mineralization at the Graphite Creek graphite deposit, Seward Peninsula, Alaska, USA. February 27, 2023. Mineralium Deposita. volume 58, pages939–962 (2023). Insights into the metamorphic history and origin of flake graphite mineralization at the Graphite Creek graphite deposit, Seward Peninsula, Alaska, USA | Mineralium Deposita (springer.com)

Carbon Nanomaterials. Millipore Sigma. Sigma Aldritch. Carbon Nanomaterials (sigmaaldrich.com)

Opinion: We can use carbon to decarbonize – and get hydrogen for free. Matteo Pasquali and Carl Mesters. July 28, 2021. PNAS Vol. 118 (No. 31) e2112089118. We can use carbon to decarbonize—and get hydrogen for free | PNAS

 

Book Summary & Review: Under A Green Sky: Global Warming, the Mass Extinctions of the Past, and What They Can Tell Us About Our Future – by Peter Ward, Ph.D. (Harper Collins Publishers, 2007)

This post is another book review on the same subject as the previous one – Mass Extinctions. This one is by legendary field geologist and paleontologist Peter Ward. The book was published back in 2007. I wrote the review in 2016.

 

Book Summary & Review: Under A Green Sky: Global Warming, the Mass Extinctions of the Past, and What They Can Tell Us About Our Future – by Peter Ward, Ph.D. (Harper Collins Publishers, 2007)

 

This is a fun foray into the scientific worlds of paleontology, paleoclimatology, geology, and mass extinctions. The book reads like an adventure story, or rather a detective story – trying to piece together geologic clues from the past to determine what caused the mass extinctions of the past, what processes were involved in the preceding and subsequent years, and how they compare to today’s global warming challenges. The author and his colleagues visit outcrops and sedimentary sequences all over the world, sometimes in isolated places and harsh environments.

 

The first place worked is the Muller Canyon area of Nevada where rocks at the end of the Triassic period are exposed. I have done some rock-hounding and geologic mapping in central Nevada in the much older rocks of the Valley and Ridge in the sagebrush desert areas. It’s a great place to look at rocks. At the time geologists were looking for evidence of asteroid impact at the end of the Triassic as evidence was found at the end of the Cretaceous in the mass extinction that wiped out the dinosaurs. No convincing evidence has been found for impact at the end of the Triassic there, only a loss of many fossil species and a thick siltstone nearly bereft of fossils. If it wasn’t asteroid impact was it climate change, he considers. Eventually, he builds up a model, a case, that it was indeed fast climate change, with rapid global warming and strong positive feedbacks that led to massive amounts of CO2, methane, and eventually other toxic gases like H2S bubbling out of the ocean and accumulating in the atmosphere, raising temperatures and making it hard to exist for many species. About 60% of all species on earth were lost in the mass extinction event at the end of the Triassic.

 

Next he ends up in the summer of 1982 in the Basque region, in the Pyrenees Mountains between France and Spain. Here he meets up with another geologist, Jost Wiedmann, a biostratigrapher cataloging, correlating, and dating fossil assemblages throughout the world. He noted that the extinction of ammonites in the fossil record near the K-T (Cretaceous-Tertiary) boundary was gradual, lasting about 20 million years, rather than immediate. Ward, with a fresh Ph.D., was interested in why the ammonite cephalopods went extinct at the K-T event after a 360 million-year biological success and their cousins, the chambered nautilus, survived. He also studied wild nautilus by diving in the Pacific off the coasts of New Caledonia and Fiji.

 

A paper came out in 1980 by Luis and Walter Alvarez, a father and son team from the University of California, Berkeley that strongly advocated that the K-T extinction event was the result of an asteroid impact. Catastrophic environmental changes, particularly a long-lasting “blackout” from massive amounts of particulate matter in the air, they proposed, were the mechanism of the mass extinction. Ward and Wiedmann found no ammonites within 15 meters of the proposed impact layer.

 

Mass extinctions were recognized in the fossil record in the 19th century but were attributed to “catastrophism,” typically worldwide floods like the biblical flood. Such ideas were tossed as the science of paleontology developed further. The two largest mass extinctions divide the stratigraphic record into three main eras: the Paleozoic, the Mesozoic, and the Cenozoic. There are five main mass extinction events noted in the geologic record - from oldest to youngest: 1) Ordovican, 2) Devonian, end of Permian (Permian-Triassic), end of Triassic (Triassic-Jurassic), and end of Cretaceous (Cretaceous-Tertiary, or K-T).

 

Ward talks about a split among vertebrate and invertebrate paleontologists in the 1970s where views on mass extinction were a factor: the vertebrate paleontologists did not think the mass extinctions occurred, only that the fossil record was missing. Evidence is now much stronger that the mass extinction indeed did occur and there is little dissent from that view. Two types of mass extinction were proposed: slow and gradual ones due to climate change, changing sea levels, disease, and predation; and rapid catastrophic ones characterized by the sudden disappearance of a large number of fossil biota in the record. The slow extinctions could not really be tested, only theorized. When asteroid impact became seen as a plausible mechanism for extinction there was at least something to look for – iridium and altered quartz that is associated with impacts.

 

The Alvarez’s paper began a new paradigm, or revolution, in thinking about mass extinctions, that they weren’t slow and gradual and due to climate change but fast and due to asteroid impact and its after-effects which include climate change. He puts this in the context of Thomas Kuhn’s “Structure of Scientific Revolutions.” Much evidence for a K-T boundary impact was accumulated: iridium, “shocked quartz,” spherules, and carbon isotope ratio changes which indicated a rapid loss of plant life presumably due to fire. However, some other geologists had another explanation: volcanism involving “flood basalts” and associated ash and lava flows. The impact vs. volcanism battle went on for over a decade. Flood basalts strongly correlated to all mass extinctions and even minor extinctions. Iridium, shocked quartz and spherules could also be associated with volcanism. Ward suggests that the geochemical evidence for impact was strong because they found what they were looking for in the impact layer but the fossil evidence required looking before and after in different places where the intervals were preserved.

 

He tells of an odd experience stalking the Cretaceous-Tertiary boundary in France at a beachside outcrop where there was a large group of tanned naked frolicking gay men while he hammered rocks in geologist garb! Here he finds 12 species of ammonites in abundance near the boundary where in other places they seemingly died off gradually – here they did not until the actual boundary layer, which is further evidence of the asteroid impact. Ward proves that impact cannot kill off just what would become microfossils but macrofossils as well. He presented his findings at a conference where Jost Wiedmann was in attendance after Wiedmann asserted that impact was not the cause and that the extinction of the ammonites came slowly. Wiedmann listened to his talk then left and never spoke to Ward again – dying a few years later, as Ward explains, his life’s work disproved by an apprentice. Science can indeed be a sad world. By the end of the 1980’s the evidence for impact as the cause of the K-T extinction was very strong. The 120-mile wide impact crater was found (in the Yucatan peninsula of Mexico) and both the geochemical and paleontological evidence supported a very rapid mass extinction. The problem, notes Ward, is that now all the other mass extinctions were assumed to have been caused by impact, as the new “paradigm” took hold.

 

Ward’s further studies in the French Pyrenees examined the quick (geologically speaking) recovery of life in the Late Paleocene of the Tertiary Period the first 5 million years after the K-T extinction event. The new fossils are of species still around today and indicate the area was warmer as they were tropical species. Oxygen isotope ratios found in shell material provide a very good record of temperatures when they were made. Analysis of oxygen isotope ratios from bottom-dwelling (benthic) organisms from the Antarctic a few million years after the K-T boundary showed that the basal ocean water there had anomalously warmed over a short period of time. The warmer water in the polar high latitudes (both Arctic and Antarctic) was also found to be more depleted of oxygen which caused an extinction of benthic organisms here at the Paleocene-Eocene boundary a few million years after the K-T asteroid impact boundary. The benthic organisms were not affected directly by the impact. The suggestion was that the oceanic conveyor belt which transfers heat to and from depth in the ocean was somehow shut down – presumably by the warm surface temperatures. This became known as the Paleocene thermal event. The event was confirmed to have occurred on land also by comparing patterns of carbon and oxygen isotope ratios in well-measured fossil assemblage sections in Wyoming. Here many exotic forms of mammals were found, many now extinct. The Paleocene thermal event is considered a minor extinction event. More evidence was searched for in Aeolian (wind) deposits – basically dust that made it to the ocean floor. The amount was reduced and extremely reduced at the point of the event suggesting low wind conditions – typically as a result of prolonged arid weather. Also found was volcanic ash and indeed a great uptick in volcanic activity 58-56 million years ago. Estimates of seawater temperature differences from equator to poles (now 45 deg C) then shifted from 17 deg C to a mere 6 deg C, suggesting a quite unusual homogeneous ocean temperature. The basic mechanism of the Paleocene thermal event is thought to have been volcanoes spewing carbon dioxide with the CO2 heating up the surface of the planet and later the ocean, shutting down the deep-water circulation conveyor belt. The event ended after the volcanism subsided and later when the CO2 levels finally dropped. By 2000, other minor extinctions began to show similarities to the Paleocene event.

 

He ends up in the Southern Tunisian Desert in 2000 at one of the best exposures of the K-T boundary. This time they took small cores with the goal of discovering the magnetic stratigraphy as Alvarez and colleagues did in other sections. Here there is a six-foot layer of black rock in an otherwise 100ft thick cliff of white limestone. This black layer can also be found in Italy, England, Wyoming, Colorado, California, offshore British Columbia, and Alaska. This represents an abrupt change to anoxic (oxygen-depleted) water. This extinction and others were now firmly linked to warming oceans.

 

Next, he explores the Permian mass extinction, the “mother of all extinctions” and the Great Dying, along the Caledon River in South Africa. After ten years of studying the K-T boundary, Ward was now fossil hunting near the Permian-Triassic boundary for land animals and terrestrial fossils. The P-T mass extinction resulted in the loss of up to 90% of species on Earth. He found one of the best outcrop sections of the transition and noted the difference between the K-T and P-T boundaries’ fossil losses – The P-T losses were more gradual and seemed to be the result of many small events and one big one, rather than one abrupt big one as in the K-T asteroid impact. No asteroid impact was implicated here even though at the time he was looking for one. The P-T boundary was associated with global warming, an anoxic ocean, and volcanic activity via flood basalts from the massive Siberian Traps – a source of CO2 to heat everything up. However, the impact advocators also found what they thought was evidence – so-called “buckyballs” or “fullerenes,” geodesic-dome-shaped carbon molecules named after Buckminster Fuller, that were thought to be of extra-terrestrial origin – thus suggesting impact. However, no iridium was found. NASA scientists reported that they may have found an impact crater that caused the P-T extinction in 2003. In 2006, scientists at Ohio State University reported a large impact crater deep in Antarctic ice detected with gravity anomaly measurements but it could not be seen or dated. Ideas of a comet impact also came about with that impact initiating volcanism but these ideas were all vague and difficult to confirm. Eminent paleontologists and geochemists got together to discuss the ideas and re-examine the evidence. They later found that the buckyballs did not come from the Permian but from much younger rocks in the Triassic and so did not correlate to the loss of species.

 

Another aspect of P-T boundary time was increased atmospheric methane, a greenhouse gas that would have heated things up. Extinction of many plant species occurred and subsequent increases in sedimentation rates. Tropical species appeared where there were previously temperate species. Increased volcanism, repeated changes in oceanic circulation, and presumed methane hydrate melting impulses are also in evidence. Impact as a possible cause for the Permian extinction has been rejected by the majority of scientists.

 

 A group led by Harvard paleobotanist Andrew Knoll beginning in 1996 proposed that the Permian extinction was similar to the Precambrian extinction of 600 million years ago. Similarities were a stratified ocean with oxygen near the surface but depleted at depth and large amounts of organic material as bottom sediments. When this changed, possibly due to plate tectonics, the deep ocean carbon began to be liberated to surface water and then to the atmosphere through large bubbles. The P-T boundary isotope changes showed a series of perturbations rather than a single one as the K-T had shown. This suggested multiple events over several million years.

 

In 2001 Ward ended up in the Queen Charlotte Islands off the coast of British Columbia to study well-exposed sections of the Triassic-Jurassic boundary, the T-J extinction being responsible for the loss of about half of Earth’s species. They wanted to get auger cores stratigraphically through the boundary to compare isotope signatures to the other extinctions. They did so in 1996 and found a main single event but did not get very far into the Jurassic section where they now hoped to see if there were multiple perturbations as there had been in the Permian. That is indeed what they found. However, iridium was recently found in several localities in some of the best T-J boundary exposures in the Newark Basin and Connecticut River valley areas of New Jersey, which suggested impact. However, the amount of iridium was quite small compared to the K-T iridium. The proposed impact crater in Quebec was later dated to be about 15 million years too soon to have caused the event. The impact from that massive crater apparently did not cause any significant extinctions – which suggests that the effects of asteroid impact may have been overestimated.

 

In 2004 he returned to the Queen Charlotte Islands to look at older rocks on the distant islands to see if extinction was single or multiple, gradual or abrupt. He digs ammonites beginning about 12 million years before the extinction and notes a classic slow gradual decrease in species of them and other fossils. He notes that while his early career was involved in showing what was once thought to be a gradual extinction at the K-T boundary was actually abrupt, now he was showing what was presumed by many to be a sudden extinction at the T-J boundary was actually a slow gradual one. The progression seemed to be that ammonites first reduced their variety as some species died out then a new species of clam, Monotis, appeared in abundance, only to be reduced as the extinction got worse. Monotis might possibly have been adapted to lower oxygen sea bottoms. Better dating techniques by finding a volcanic ash bed to date revealed that the Rhaetian stage of the late Triassic, with low oxygen seas largely devoid of life, lasted up to 11 million years. After the Rhaetian stage came the Norian stage when the rest of the bivalves and ammonites died out so Ward sees this as two extinctions, one quite gradual and culminating at the end of the Rhaetian and one more abrupt but still gradual ending at the end of the Norian stage. Subsequent fossil work in other places showed extinction pulses occurring into the Jurassic as well. To sum up it was now thought that most extinctions were gradual and only one, the K-T, was definitively associated with impact, the others being logically ruled out. Thus the ‘extinctions were caused by asteroids’ paradigm was given up except for K-T.

 

The next chapter finds Ward diving in a pristine coral reef near Palau in tropical Pacific Micronesia. This was back in 1983. Ward was a long-experienced diver. He lost a fellow diver in the past who had passed out during a deep dive and Ward got a serious case of the bends attempting to save his life by bringing him up fast. His friend died but Ward suffered chronic bodily pains and a permanent limp from his own injuries. Here they were studying the nautiluses, along with the ammonites, another cephalopod. The ammonites survived many extinctions but were wiped out at the K-T boundary in the Cretaceous. They tagged the nautiloids and found that they dived deep during the day and came closer to surface at night. That may have been why they survived the K-T and the ammonites who stayed in shallow water did not. It seems that while the Permian, Paleocene, and Tertiary extinctions wiped out bottom dwellers the K-T extinction wiped out the surface dwellers.

 

It was still unclear exactly how a slow gradual change of climate could have killed so many species several times in the past. New ideas were forming. Microbiologists studying anoxic lakes found some new fossils, chemical fossils, known as biomarkers. They did not leave behind skeletal remains but chemical remains in the lake sediment. Toxic hydrogen sulfide gas (H2S) was one chemical marker and calculations by one author, Kump, suggested that the amount of H2S was significant in the Permian – 2000 times that produced by volcanoes. The Kump Hypothesis also noted that the H2S would have destroyed the ozone layer and evidence from Greenland of fossils damaged by ultraviolet light suggests this may have occurred. Destruction of the ozone layer would mean a decrease in phytoplankton, the base of the food chain. Another hypothesis suggests the ozone layer could have been destroyed by particles from a supernova. With increased CO2 and methane bubbling up from the sea in a hot Permian, the H2S would have been more toxic as it is in a warmer environment. Evidence was found of H2S–producing microbes in the Permian throughout the world. Since sea level was low at the time they also looked for evidence of eroding phosphorous which would have been a nutrient for microbes to accelerate their growth.

 

Next, he ends up near his hometown, Seattle, looking at fossils in non-bedded limestones deposited in a “mixed” ocean of little oxygen variation with cold areas at the poles and warm ones at the tropics, as now, or since the Oligocene, about 30 million years ago. Older rocks show black bedded rocks deposited in an anoxic ocean bottom. Pyrite is common in these rocks.  Anoxic bottoms are filled with black shales, around since 3.5 billion years ago, and sometimes with very well-preserved fossils of life forms that fell into the sediment with their forms preserved. The famous Burgess Shale is one example. There are two types of stratified oceans, he notes: one with low-oxygen bottoms which supports some life, mostly microbial; and one entirely devoid of oxygen which supports only microbes that utilize sulfur for food and give off H2S as a waste product. The latter is known as a Canfield ocean. Canfield oceans were toxic to life. They are thought to have been around in the Precambrian inhibiting the development of life. The eukaryotes require microbes to fix nitrogen, a needed nutrient, for them. The sulfur-imbibing microbes do not fix nitrogen, instead inhibiting it. Chemical biomarkers also suggest that the T-J extinction is associated with pulses of short-lived Canfield ocean conditions. The oceanic circulation, the conveyor belt, may be the key to the changing ocean states. There is strong evidence that the conveyor belt shut down (or shifted) in the Paleocene and now it appears that this happened in the Permian as well. Of course, the continents were in different places in these past times due to plate tectonics so the actual circulation patterns were different than today but a similar mechanism is still likely to have been in play. The shift in ocean circulation in the Permian was thought to have brought anoxic water to the deep ocean which allowed the H2S-producing microbes to thrive and upwelling of poisonous bottom-waters. If the Paleocene had H2S-producing microbes they were at far lower concentrations than in the Permian. He compares extinctions from Anthony Hallam’s and Paul Wignall’s 1997 book, Mass Extinctions and Their Aftermath, which was written when impact was still thought to be associated with most or all extinctions. Even so, their data revealed that of the 14 mass extinctions that were cataloged, 12 were associated with poorly oxygenated oceans as a major cause. The three “kill mechanisms” are now thought to be heat, low oxygen, and perhaps H2S.

 

Next, he ends up in Namibia in Southern Africa where the scorching hot Kalahari Desert is flanked by a foggy Atlantic Ocean that is very cold. Models of atmospheric CO2 and O2 concentrations of the past can be made using changes in sedimentation burial rates. One of the main modeling setups for paleoclimatological studies is GEOCARB for CO2 and GEOCARBSULF for oxygen. Modeling indicates that CO2 levels were very high from the Precambrian to the lower Permian – from about 5000 then down to about 300 PPM, rising back up to 3000 near the Permian extinction. Modeling also indicates that all of the mass extinctions of the past with the exception of the K-T impact-caused extinction, are associated with maximum or ‘rising toward maximum’ atmospheric CO2 concentrations. Thus rapid rises in CO2 correlate strongly to mass extinctions. This implicates our anthropogenic CO2 increase as a potential cause as well – if it were to rise ever higher – though likely far beyond current projections. Another way to estimate past CO2 concentrations is through fossil plant leaves. These readings on leaf stomata confirmed the CO2 estimates modeled.

 

Ward summarizes the sequences of events that are thought to have taken place in these mass extinctions: 1) world warms due to increase in greenhouse gases, initially from volcanoes; 2) The ocean circulation system is disrupted or shut down; 3) the deep ocean becomes de-oxygenated then shallow water suffers the same fate; 4) deoxygenated shallow water bottoms with some light penetration allow green sulfur bacteria to grow and produce H2S which rises in the atmosphere and breaks down the ozone layer with the UV light killing off phytoplankton. – The high heat and H2S also cause mass extinction on land. He notes significant variability in each extinction and calls the model the ‘conveyor disruption hypothesis.’ He envisions seas full of gelatinous bacterial mats, stromatolites which would later become food for terrestrial herbivores as (very slow and weak) waves brought them in. The ocean would look serene and waveless and be purple due to floating bacteria. Thick bubbles of various sizes filled with poisonous H2S would belch from the sea giving the sky a green tint – thus the book’s title. The bottom line is perhaps the realization that it is mainly increased atmospheric CO2 and other greenhouse gases like methane that serve as the trigger for mass extinctions.

 

Next, he talks about bridging all the varying scientific disciplines involved in modern climatology and paleoclimatology. For much of the book he also addresses motivations for reward and prestige among scientists and how that can affect their work.

 

He goes into the carbon dating work of Minze Stuiver of the Quaternary Research Institute. He dated the Greenland ice cores year-by-year dating back 200,000 years. Using mass spectrometers they were able to accurately approximate temperatures and CO2 levels. What they found is that the current climate on Earth is quite aberrant even for recent geological history. Temperature changes of up to 18 degrees F over a few decades were more common in the past.  Before 10,000 years ago it is thought that storms the size of the major hurricanes occurred several times a year. At about 10,000 years ago a period of unprecedented calm apparently set in. Humans settled and mastered agriculture during this new period of calm. The records of the ice cores match quite well the planetary and orbital cycles proposed by  Milankvitch with those cycles being the triggers for glacial and interglacial periods. One of the unknowns that Ward emphasizes is how much CO2 and global warming would it take to alter the oceanic circulation system. Wally Broecker thinks it could slow down but is unlikely to shut down with even say 1000 PPM CO2. It may be changing now. Fresh water from melting northern ice could be a prime trigger for changing the conveyor belt. Ward goes through smaller time period climate cycles like the Dansgaard-Oeschger cycles and the cycles of floating melting ice dropping cobbles they were carrying, now called Heinrich events – seen in the ocean floor sediments. For 90% of the last 100,000 years the earth has been in an ice age so these are anomalous times indeed. Before 8000 years ago the conveyor belt is thought to have been less stable. The current stable period is a precarious stability, scientists suggest. Biodiversity strongly correlates to this stability. The implication is that the “on-off” conveyor belt tips the earth’s climate to one of two stable states: the cold one that has taken up 90 % of the last 100,000 years and the warm one we are in now.

 

He next visits Manua Loa in Hawaii where atmospheric CO2 has been dutifully measured since the 1950’s – as part of a Canadian TV documentary about climate change. In addressing climate history of the last 8000 years Ward gives the data from William Ruddiman which shows that humans have been affecting CO2 and methane levels since the advent of agriculture, forest burning to clear land, flood for rice paddies (which is major source of methane), and livestock agriculture (another major source of methane). The CO2 range of the last 200,000 years has been between 180 and 280 PPM with most of it in the small end of the range since most times were ice age times. At the beginning of the Industrial Age CO2 levels were at 280 PPM and now they are above 400 PPM, a level unprecedented in the last 200,000 years. CO2 can also directly cause limited extinctions of certain species in the form of increases in ocean acidity and this is happening now in cases of coral bleaching. The changes in ocean pH will likely persist for thousands of years, he notes, thus changing life patterns. While there may have been times of high ocean acidity in the past he suggests that they have not been as high as they are expected to get soon for quite some time – perhaps 100 million years – since certain species were more adapted in the past to higher acidity – however, the abrupt changes now due to anthropogenic CO2 are too fast for many species to evolve adaptations. The present rate of the rise of CO2 seems to be faster than at any period in the past and global average temperatures have not been this warm since the Eocene epoch 60 million years ago which followed a mass extinction.

 

Next, he delves into the Eocene epoch looking at fossils along the Pacific coast of North America. He notes that this hot time was a time of very high sea levels compared to today. This area was tropical during the Eocene as evidenced by abundant palm and crocodile fossils found as far north as the Arctic Circle. He explores the climatic features of the Eocene and compares them to what a 1000 PPM atmospheric CO2 level world might be like as after we humans create it. First, he notes that the tropics are the source of many of the human diseases that affect us. He suggests that tropical peoples in particular have developed coping mechanisms for the heat in the form of various local drugs. I am not so sure they have a monopoly on that. He mentions the widespread use of betel nut, kava root, and khat. Of course, the same could be said for alcohol and cannabis in temperate climes. The prevalence of mosquitoes makes malaria and other diseases more likely as well. He goes through all the typical scenarios of global warming effects: melting ice, rising sea levels, changing weather patterns, submerged cities, storm surges, changes in habitat patterns, etc. He notes that the temperature rise in the Arctic has been 20 times that of other places on Earth and is quite worrying to scientists. Are effects underestimated? Overestimated? No one knows for sure but some attribute a significant amount of deaths now to global warming in the form of malaria and malnutrition. He invokes the view that hurricanes will worsen in both magnitude and frequency, popular at the time of publication. However, that has not occurred and may end up being a misattributed global warming effect. The increase in hurricanes from 1990-2004 may be part of a natural cycle. Heat waves are another effect that has increased. Suggestions of war and famine are speculative. Cereal grain crops may not yield well in a more tropical climate.

 

Next, he discusses climate and the possibility of re-entering an Eocene-like epoch with famed University of Washington climate scientist David Battista. Windless tropical conditions in some temperate areas with super hurricanes pounding the equatorial tropics. The conveyor might change into a form where warm water from the tropics sinks much further south in the Atlantic which would freeze Western Europe perhaps giving the false impression to some of an impending ice age. Then when the sinking low salinity freshwater did not sink deep enough a situation of lower oxygen could develop at ocean depths resulting in the next chain in the link of mass extinctions that have occurred in the past.

 

He goes through some more speculative scenarios at different CO2 levels but it really is hard to know how things will play out and there are still uncertainties about that.

 

Great book overall by a geologist who wears the scars of his work and his craft through an adventurous but often lonely existence in far-off corners of the world as well as in the academic realms.

Book Summary & Review: The Sixth Extinction: An Unnatural History – by Elizabeth Kolbert (Henry Holt & Company, 2014)

      What follows is a book review I wrote in 2018 of a book published in 2014 after reading the book and attending a talk by the author at a local university lecture event. As mentioned, the author acknowledges that the title of the book may not be ideal as it is generally thought that although extinction rates have climbed to alarming levels, especially in certain regions, it is not thought that we are currently undergoing a mass extinction event.

 

Book Summary & Review: The Sixth Extinction: An Unnatural History – by Elizabeth Kolbert (Henry Holt & Company, 2014)

 

This was a fair to good book, mainly a history of mass extinctions and of extinction in general. Kolbert is a writer at The New Yorker and has written about environmental and science topics. I moved this up on my review list since the author just gave a talk about the book at the local university.

 

She begins with the recent evolutionary success of humans who have managed to vastly increase their population in the past 100 years and vastly affect their environments and planet to the point where we are directly influencing an unprecedented acceleration of the rate of extinction of many species, mainly through habitat loss. Humans began causing extinctions thousands of years ago by hunting animals to extinction, including isolated island species, especially flightless birds, and very likely megafauna as well. When we discovered and developed fossil fuels and subsequent technologies, we expanded our population which also expanded human-caused extinctions.

 

The first chapter is about the Panamanian golden frogs, once extremely populous, now disappearing. She travels to the area to observe efforts to keep the frogs from going extinct. Frog and amphibian extinctions in general have been accelerated recently, even though some have been present on Earth for hundreds of millions of years and several made it through all of the previous mass extinctions. A fungus in the chytrid family, known as Bd for short, is the culprit killing the Panamanian golden frogs.

 

She talks about what is known as the ‘background extinction rate’ which is the normal rate of extinction for a class of organisms. For example, the current background extinction rate for mammals is 0.25 per million species-years, or roughly one lost mammalian species every 700 years. In contrast, mass extinctions cause substantial biodiversity losses rapidly and globally. They happen close enough in time to be called events, although an event may last hundreds of thousands of years. Mass extinctions often mark the boundaries of geologic periods. The Big Five mass extinctions were: 1) End of Ordovician, 2) End of Devonian, 3) End of Permian, 4) Late Triassic, and 5) End of Cretaceous. According to paleontologist David Raup: the history of life consists of “long periods of boredom interrupted occasionally by panic.” There have been many lesser extinction events as well. Amphibian background extinction rates have not been calculated due to a dearth of amphibian fossils, but it is thought to be less than that for mammals. However, in recent times, most herpetologists have seen several extinctions of amphibian species. In fact, now they are considered the world’s most endangered class of animals, possibly as much as 45,000 times the background extinction rate! Many reef-building corals, fresh-water mollusks, sharks and rays, and mammals are also endangered.

 

The Bd fungus was thought to have been introduced by importing frogs from other places that were less affected by it. The introduction of invasive species and new diseases is another result of human travel. Humans have managed to globally re-shuffle species, both purposely and accidentally, on an unprecedented scale.

 

Oddly, humans did not understand that species went extinct until fossils were interpreted by paleontologists. There were theories and ideas about fossils, often referred to as the flood of Noah in Genesis. In the late 1700’s the French naturalist Nicolas-Frederic Cuvier interpreted Mastodon fossils from America as remnants of an extinct species. The author visits a paleontology museum in Paris that houses Cuvier’s specimens and sketches. It was Cuvier who established extinction as fact, she notes. He found many fossils in nearby gypsum quarries. The discovery and reconstruction of the bones of the Ohio mastodon by others would cement Cuvier’s idea of extinction. In 1812 Cuvier published a four-volume compendium on animal fossils. Cuvier was also involved in the early study and identification of dinosaur fossils. Cuvier’s success (perhaps modest by modern standards) was based on his keen knowledge of anatomy. His senior colleague Jean-Baptiste Lamarck, who asserted that there was a force pushing beings toward complexity (an idea that later merged into Darwin’s evolution) opposed his idea of extinction.

 

Cuvier believed extinctions were caused by catastrophic events that happened very quickly. Not much later this idea would become known as ‘catastrophism’ and it was the basis of early geological theory in the early-mid 1800’s until Charles Lyell appeared on the scene. Lyell observed rock layers and concluded that geologic processes like sedimentation and erosion were very gradual over long periods of time. He also thought extinction was a gradual process. Darwin read his books as a young college student at 22 as he traveled on his famous voyage to the Galapagos Islands and beyond to the South Pacific. He experienced a horrific earthquake while in Chile and measured the local ground uplift with surveying instruments to eight feet. These and other experiences convinced him of the truth of Lyell’s ideas as Lyell also talked about uplift and subsidence, noting that over long periods of time, accumulated uplifts could make mountains. Darwin noticed that coral reefs and atolls were a result of the interplay between biology and geology in that sea shelves subsided (dropped) and reefs moved accordingly to waters of shallow depths. He presented the idea to Lyell who was delighted and revised his idea of reefs which erroneously thought underwater volcanoes were the underlying source. Lyell was wrong about other things – ie. catastrophes and destructive events do have a place in geology. Darwin’s key idea of natural selection was also rooted in Lyell’s ‘gradualism’ and followed Lyell’s famous principle that “the present is the key to the past.”

 

She visits a museum in Iceland that houses the last known specimen of the great auk, an extinct bird, large and flightless, last known from the mid-1800s. Once numbering in the millions, the bird is one of many species of animals wiped out by humans for food. Darwin also acknowledged human-caused extinction, which in some cases could be directly observed as hunted species became more and more rare.

 

Next, she considers the ammonites and the work of the Alvarez’s (Luis and his son Walter) in determining their demise was caused by an asteroid impact that defined the end-Cretaceous mass extinction, the stratigraphic boundary being known as the K-T boundary. Paleontologists went around the world looking for the K-T boundary contact in outcrops and successive rock layers before and after, Geochemists got involved in looking for evidence of asteroid impact minerals, mainly iridium. Finally, the impact crater was actually found on the Yucatan Peninsula of Mexico. It was not the impact itself that caused the ammonite extinction, wrote the Alvarez’s, but likely the dust which blocked out the sun which killed plants and animals. This is the event that wiped out the dinosaurs. Living things near the impact were simply vaporized. The atmosphere was altered and the ocean chemistry. Species that could live in deeper ocean water had better survival rates. Ammonites can be seen very well in the fossil record to decrease in variety and in amount but in this case, the seemingly gradual was really precipitated by a single event. The end-Cretaceous (K-T) mass extinction is thus far the only one (probably “the” only one) confirmed to be from an impact event.

 

Next, she considers a history of the science of extinction in terms of Thomas Kuhn’s “paradigm shifts” in his historical/psychological study of scientific revolutions. The first paradigm shift was acknowledging extinction which happened with Cuvier and contemporaries in the 1800’s. Lyell’s focus on the gradual was another shift. That idea held up until evidence for asteroid impacts showed that mass extinctions could result from a single catastrophic event. Of course, in reality, both gradual and catastrophic processes operate in geology with the catastrophic simply being much rarer than the gradual. 

 

She goes to Scotland where geologists are looking at graptolite fossils at the end-Ordovician (444 million years ago) boundary defined by the first major mass extinction. Life then was in the sea, having “exploded” in variation in the previous age, the Cambrian. They are looking for the record in the rocks where the sea went from habitable to inhabitable. After verification of the impact explanation for triggering the end-Cretaceous mass extinction, impact was a popular idea for other mass extinctions. However, the lack of iridium and other factors favor other explanations. The current theory in favor of the end-Ordovician mass extinction is that of global cooling and glaciation of a previous greenhouse climate. The glaciation dropped global sea levels drastically which ruined sea life habitat and ocean chemistry changed drastically as well. This dropped previously high CO2 levels which cooled the planet further. One idea is that it was the spread of mosses on the land that decreased CO2 levels and triggered the process. She considers this idea, that it was plants that caused the first major mass extinction. The end-Permian extinction also appears to be a result of changes in climate.  A massive increase in atmospheric CO2 happened then, 252 million years ago. The seas warmed. Reefs collapsed. Some scientists think the CO2 came from volcanos. Some also think that the conditions eventually favored bacteria that produced hydrogen sulfide and that this extended the die-off due to a poisoned atmosphere.

 

She explores the notion that we have entered a new geologic age informed by humans and the effects of their population growth and technology. Dutch chemist Paul Crutzen termed it the Anthropocene. He noted that humans have transformed between a third and a half of the land surface of the earth, dammed and diverted most of the rivers, added excess nitrogen to the biosphere through fertilization, overfished the oceans, and used half of the world’s freshwater runoff. We have also altered the chemical composition of the atmosphere and the ocean.

 

Next, she goes to an area in the Tyrrhenian Sea off the coast of Italy where there is an active underwater volcano system that spews CO2 from vents on the ocean floor. Scientists there can study the effects of increased ocean CO2 as one moves closer or further from the source. The extra CO2 produced by humans is partially absorbed by the ocean and this lowers its pH making it more acidic. Scientists there study the effects of more acidic ocean on sea life, particularly life that makes calcium carbonate shells. Some creatures are more adaptable than others, but few can live in the very low PH waters very near the vents. The same is true of a globally acidified ocean – some species will thrive, and others suffer. The general prediction is of loss of biodiversity. Ocean acidification was involved in the end-Permian and end-Triassic extinctions and possibly the end-Cretaceous as well as the Toarcian Turnover 183 million years ago in the early Jurassic. Shelled organisms that use calcium carbonate, ie. calcifiers, need to adjust their internal chemistry to the ocean chemistry. Typically, they do that through evolution so the speed at which they can evolve will be a factor. There are no calcifiers near the vents.

 

Continuing with the effects of ocean acidification on calcifiers she travels to the Great Barrier Reef region in the South Pacific. Corals are a calcifying superorganism. Darwin was right that subsidence is a major factor in reef-building. She travels to One Tree Island to observe the work of atmospheric scientist Ken Caldeira and others. Caldeira thinks that the coming ocean acidification will surpass that of the last 300 million years. Thus, coral reefs could be the most vulnerable of ecosystems. They are already being affected. She explains pH and calcium carbonate saturation. The sea provides a buffering effect on acidification, but the amount of CO2 is increasing the amount of carbonic acid to exceed the buffering effect. In the geologic record, limestone-based reefs have come and gone but those reefs consisted of different organisms, many now extinct. Modern coral reefs face other threats too: overfishing that increases algae which compete with the corals for nutrients, agricultural runoff which also spurs algae growth, and siltation resulting from deforestation. Increasing water temperatures cause the corals to lose their colorization mechanisms. This is known as “coral bleaching” and can lead to the death of reefs.

 

Next, she heads to the Andes in Peru where researchers are studying the effects of climate on the region’s immense biodiversity through observing plots of trees confined to very specific elevations based mainly on temperature. These species are very specific in their requirements. Some species can move upslope faster than others by projecting seeds but others can succumb more easily to rising temperatures. The worry here is that many of the less versatile species will go extinct. The logic is that since there is much greater species variation in the tropics there will be much more climate change-related extinction there. The trees also host other species of insects, etc. that also have rather exacting condition requirements. One theory simply holds that the tropics have more species precisely because those species are more condition-specific. Another theory notes that it is the age of the tropics in terms of less disruption over time than in temperate and polar zones. They have had more time to diversify. New species are still being discovered in the tropical regions. Species do migrate but if the rate of climate change, mainly increasing temperatures but also differing water conditions, exceeds the rate of migration, some species won’t make it. She explains the species-area relationship graph (S=cAz (z is a superscript – power). What humans change mainly is A or area, changing the availability of certain types of land through development and agriculture. One prediction is that by 2050 9-13% of species will be committed to extinction under the minimum warming scenario and 21-32% by the maximum warming scenario. Others disagree, saying species are better at adaptation and moving. Most do not think that climate change and habitat destruction will cause a major extinction like the Big Five but may approach some of the minor ones. (Thus, the book’s title may be deceptive. Even the book’s subtitle is questionable since extinction is quite natural as 99.5% of species once in existence have gone extinct. A person asked this question at her talk, and she conceded that it may not have been the best subtitle). The tropics have other threats: illegal logging, illegal ranching, and illegal mining. Some have noted that in a warmer world, species’ overall biodiversity will eventually increase rather than decrease as evidenced in the warm Eocene of 50 million years ago. The problem now is that warming is happening much faster than species can keep up.

 

Next, she moves s over to the Amazon in Brazil to observe some of the “reserves” kept from development – patches or fragments of rainforest. There she visits famed conservationist Tom Lovejoy who convinced the Brazilian government to preserve parts of the area for scientific study. The experiment started in the 1980’s. Here also, new species continue to be discovered. The preserved plots are essentially islands among logged-out areas. Like the Andes experiment these areas are megadiverse and species are very specific in actions and in conditions required for thriving. High species diversity also means low population density and so species become isolated by distance. Such populations are much more susceptible to extinction. She notes that while primary forest is declining in the Amazon the amount of secondary forest is growing so this may slow the high species extinction rate predicted somewhat. Timbered forests will regrow if not further developed. There are so many species in the tropics it is hard to count them, let alone count how many have gone extinct.

 

Next, she considers what has been called the “New Pangaea,” the globalization of species by virtue of human introduction, both deliberate and accidental. Thus, the geographic distribution of some species has advanced hugely. Here she focuses on the loss of bats in Eastern North America due to a fungus that causes what is called “white-nosed syndrome.” This was first observed in 2007 and is killing bats by the millions, especially when they hibernate in caves and mine shafts in the winter. Ballast water of ships, hitching rides on people and cargo in planes, and on people’s stuff and shoes from car travel are some of the ways species expand their distribution. Invasive species have become problematic in many places although some are more problematic than others and some may also be beneficial, ie. introduced species are not always invasive species but often are. Here she explores some of the stories of introduced species. They often become invasive because in new areas their usual predators may not be around. Introduced species can actually hunt other species to extinction as happened with the brown tree snake accidentally introduced from Papua New Guinea to Guam where it extinctified some birds and bats. It merely did what humans do – succeeded at the expense of other species. As in the story of the American chestnut tree succumbing to a fungus that was common to Asian chestnut trees that the fungus evolved with, the fungus killing American bats is not harmful to bats in Europe from where it was likely introduced. The same is true of the chytrid fungus killing the Panamanian frogs. Novelty can kill. She goes through a surprising list of species introduced to North America: dandelions, honeybees, earthworms, queen-Anne’s lace, burdock, plantain, etc. Currently, the emerald ash borer is a problem here in Ohio – I have about 40 or 50 of these trees dying or dead within about 500 ft of my house. Some will fall a limb at a time or maybe from the base. Others nearer will have to be cut down in the next few years. Zebra mussels and Asian carp are aquatic species that have wreaked havoc. Of course, humans have been introducing species from time immemorial as they traveled to new areas. It is just in recent times the process has been vastly accelerated. This has resulted in the rise of ‘local diversity.’ While local diversity has been increasing, global diversity has been decreasing.

 

Next, she visits the Cincinnati Zoo which houses (not sure if still there) a Sumatran rhinoceros named Suci. They are the oldest and smallest of the five species of rhinos today but are highly endangered. Some housed at zoos are trying to be mated to reproduce. These are known as ‘captive breeding’ programs. The Sumatran rhino, once common from Bhutan to Indonesia, is a victim of habitat destruction and forest fragmentation. There are only a few hundred left in the wild. In their case, captive breeding efforts have made the problem worse as many died faster in captivity. A few have been born in captivity so there is some hope. Other rhinos have been overhunted for their horns which are used as an aphrodisiac in Chinese medicine and apparently as a party drug where they are powdered and snorted like cocaine.

 

While in Cincinnati she also visits the nearby museum at Big Bone Lick where the old mastodon fossils that Cuvier interpreted were found. She considers whether the North American megafauna was driven to extinction by human hunters (the leading theory by far) or by climatic changes or possibly by both. Similar losses of fauna occurred in Australia, New Zealand, Madagascar, and other places. Of course, every loss coincided with the arrival and persistence of humans in those areas. She shows through scientific evidence that pre-historic humans almost certainly caused these extinctions. One issue with some of the big megafauna is that they reproduce sparingly and have one baby at a time so that even a small amount of them killed by humans could have a large effect on their population in a relatively short period of time. Other simulations have shown that the megafauna was very vulnerable to humans, that only a few hundred humans could have wiped them out over a millennium.

 

Next, she visits Germany to consider the fate of our human deep ancestors, the Neanderthal. The likelihood is that modern humans, homo sapiens, simply killed off and inter-breeded with Neanderthals. Genetic projects are underway to map the Neandertal genome, compare it to the genome of modern humans, and find out where and possibly when they diverged. Apparently, it is a slow process since getting DNA from Neanderthal bones is not easy. We now know that Europeans and Asians share more Neanderthal DNA than Africans. All non-Africans carry between 1% and 4% Neanderthal DNA. Only modern humans, not Neanderthals, used projectiles and made it to Australia, Madagascar, and other places (used boats). Paabo, the researcher there in Germany, is a leading DNA-extracting researcher in the realm of humans. He tried and failed to extract DNA from a bone fragment from 17,000-year-old homo floresiensis, first discovered in 2004 in Indonesia and identified as a new species. Then in 2010 the first bones of the Denisovans were discovered in a cave in Siberia. Paabo named the species and was able to extract DNA from the finger bone discovered. It was found that modern people from Papua New Guinea share 6% DNA with Denisovans, but that modern Siberians and Asians do not. This is likely due to ancient migration patterns. The Neanderthals used tools, and buried their dead, and some think they made art and adorned themselves, but after living in Europe for 100, 000 years there is little to show of their “culture.”

 

Finally, she explores the San Diego Zoo, specifically the place there where the DNA of extinct species is preserved. Here there are also very endangered species. One is a rare male alala, or Hawaiian crow named Kinohi. These crows can imitate human speech somewhat like parrots. They are trying to extract his sperm to mate with the few female alalas left. She talked about him in her talk.

 

Overall, this was a pretty good book and a nice overview of extinction in general. Like I said before, I don’t think the title, or the subtitle are ideal since this may not become a “mass” extinction although the rate of extinction has certainly accelerated significantly – and it is not at all unnatural. I think she talked a bit too much in her talk about the effects of climate change and the current American political climate as being unhelpful. I would have rather explored more about biology in general.