Contrasting Good and Bad Science: Disease, Climate Change and the Case of the Golden Toad 

Adapted from the chapter "Beating Dead Frogs with CO2"  in Landscapes & Cycles: An Environmentalist’s Journey to Climate Skepticism by Jim Steele

To insure the public does not become complacent as the 16-year hiatus in rising global temperatures continues, the media is spammed with untested models claiming rising CO₂ is and will spread death and destruction via food shortages and disease.

As MIT’s world-renowned oceanographer Carl Wunsch warned “Convenient assumptions should not be turned prematurely into “facts,” nor uncertainties and ambiguities suppressed…Anyone can write a model: the challenge is to demonstrate its accuracy and precision...Otherwise, the scientific debate is controlled by the most articulate, colorful, or adamant players. (emphasis added)”¹ As presented here before, the extinction of the Golden Toad illustrates the great abyss that separates the rigor of good medical science from the opportunistic models trumpeted by a few articulate and adamant climate scientists. The lack of substance in climate propaganda is revealed when we compare the details that led epidemiologists to blame a fungus and modern transportation  for the Golden Toad’s extinction.

In "Why Most Published Research Findings Are False," Stanford University epidemiologist John loannidis reported that "for most study designs and settings, it is more likely for a research claim to be false than true. Moreover, for many current scientific fields, claimed research findings may often be simply accurate measures of the prevailing bias (emphasis added).”² loannidis' paper was highlighted with other similar findings in a 2010 New Yorker article, “The Truth Wears Off,” by Jonah Lehrer. It is available online and well worth the read. That a prevailing bias allows bad science to be so easily published in medical science is worrisome. Equally disturbing, when scientific bias converges with political bias, published conclusions can be as devoid of reality as the epicycles that defended the consensus belief of an earth-centered solar system for two thousand years.

Typically medical science demands rigorous testing of any purported cause of a disease. To blame a pathogen (i.e., a bacterium, virus, or fungus) for a sickness, the researchers must satisfy a burden of proof known as Koch’s postulates. First the pathogen must be found on a diseased animal and then isolated. Then scientists must culture the pathogen and inoculate a healthy animal with it. If the pathogen causes the same disease symptoms in the healthy test subjects, then it becomes a likely candidate. Finally, to prove that pathogen had caused the epidemic, researchers must then find that same pathogen on the widespread carcasses of victims of the epidemic. Environmental conditions that existed during the epidemic should also coincide with the pathogen’s behavior under laboratory conditions.

Indeed for the past 3 decades there has been an alarming wave of worldwide amphibian extinctions and after rigorous testing epidemiologists determined that an introduced fungus was the cause. In contrast CO2 global warming advocates used spurious correlations, opportunistic models and the current global warming bias as a few adamant players including the IPCC, the journal Nature and Michael Mann repeatedly trumpeted a climate causation.

First a quick review of basic amphibian biology is helpful. You can always recognize amphibians (i.e., frogs and salamanders) versus reptiles (i.e., lizards and snakes) by the amphibians’ moist, slimy skin. To supplement their feeble lungs, amphibians absorb essential oxygen directly from the air through their skin, which must remain moist to do so. Most amphibians are also tied to pools of water because their jelly-coated eggs readily desiccate, and during their tadpole stage they breathe with gills. Lost wetlands had accounted for several past extinctions, but not this recent wave.

Some amphibians had been forced to adapt to eons of climate change cycles that naturally dried up lakes and rivers, as well as an increasing populations of predators. A few entrepreneurial amphibians discovered that their odds of survival were better on land, and many species evolved the most amazing strategies to free themselves from their dependency on standing water. For example in Chile, Darwin’s Frog (see video) lays its eggs on the moist forest floor, and the male then stands guard as they develop. As soon as the eggs show signs of emerging as wriggling tadpoles, the male swallows them; not into his stomach, but into his vocal sac. The vocal sac serves as a protected “indoor pool” in which the tadpoles grow until they metamorphose into fully developed frogs.

Throughout much of Central and South America are several species of Marsupial Frogs. Analogous to kangaroos, they grow a pouch on their backs, inside which their tadpoles develop. Most amazing of all were Australia’s two species of gastric-brooding frogs. Although they spent most of their lives in water, the female protected her offspring by swallowing her eggs. Unlike Darwin’s Frog, the eggs were swallowed into her stomach. Somehow, the deadly digestive enzymes and acid that normally flooded their stomach stop flowing until her tadpoles were fully developed. The adults then gave birth by regurgitation. Despite having adapted to millions of years of climate change, in the 1980s this marvel of nature became one of the first casualties of the new wave of amphibian extinction.

The Rain Frogs are petite frogs that lay their eggs beneath the leaf litter on the damp floors of tropical forests. The red-eyed Coqui, a national symbol of Puerto Rico (and a recently introduced pest in Hawaii), is a species of Rain Frog. These frogs have evolved the remarkable ability to undergo complete metamorphosis without ever leaving the confines of their eggs. However, they never evolved the waterproof eggshells of reptiles and birds, so the frogs’ eggs can rapidly dry out. Some species lay their eggs in moist sand along streams. Others lay their eggs on dry land beneath the leaf litter. To keep their eggs moist, the thoughtful parents periodically urinate on them. Some childhoods are simply tougher than others.

Golden Toads (Bufo periglenes) had adapted to Costa Rica’s dry season by spending their entire lives sequestered in moist underground burrows. The Golden Toads only emerged from their burrows in late March and April, to mate during the first few weeks of the rainy season laying their eggs in any temporary pools. For the remainder of the year they retreated back to their burrows. First discovered in 1966, and inspiring the formation of Costa Rica’s Monteverde Cloud Forest Reserve, this species was found nowhere else in the world. In 1987 Monteverde’s biologists had counted over 1500 healthy individuals painting their breeding pools with squirming gold. Without warning, they disappeared, and not one carcass was ever found.³

 

Dueling Extinction Theories

Martha Crump and Alan Pounds had been studying Monteverde’s amphibians and were understandably distraught by the rapid disappearance of the Golden Toad and several other local species. That year an El Niño had forced extremely dry conditions, and researchers were not sure if the Golden Toads had died or if they were simply waiting for wetter breeding conditions.⁴ However after years of total absence, it became apparent that just 25 years after their discovery, the Golden Toad had become extinct.^5,6

Pounds and Crump first suspected that extreme drying from a strong El Niño was the likely culprit; however, contradictory evidence evoked doubts. Nearer to the Caribbean Sea where rain had been more abundant, frogs had been equally decimated. Furthermore, Harlequin Frogs usually lay their eggs in streams that had never dried out, yet they too suddenly vanished. In contrast, the number of tiny “tink” frogs increased. Tink frogs (named for their metallic call) develop inside their eggs beneath the leaf litter and were the most vulnerable to extreme drying. Golden Toads were the biggest mystery. How could an El Niño extirpate an entire species that was insulated from the weather inside their burrows?

Later as amphibian biologists shared their research, it was realized that they were facing a global wave of local extinctions. Massive die-offs were not restricted to Monteverde or the effects of El Niño. Massive die-offs were observed in regions of Central and South America, Spain, North America, and Australia. In 1996, Australian researchers detected waves of die-offs that slowly spread across northern Australia. They reported that 14 species of stream-dwelling frogs, including the gastric-brooding frogs, had suddenly disappeared; in some cases in as little as three to six months. 

Contradicting prevailing global warming theory, the Australian researchers reported that the die-offs were happening at higher elevations with cooler temperatures, but not at warmer lower elevations. Die-offs also occurred during the winter but not the summer.⁷ Researchers in Central and South America also found that populations that lived at higher and cooler elevations were extirpated, while populations of the same species living at lower and warmer elevations were still thriving.^8,9 Similarly in the United States, the extirpations were happening at higher elevations in Yosemite, and during the winter in Arizona when cooler temperatures prevailed.⁶

So William Laurance from the National Institute for Research in the Amazon and his Australian colleagues hypothesized that the global population of amphibians was under attack by a rapidly spreading, exotic disease that was dependent on cool, wet conditions. They suggested that human activities such as the pet trade and invasive species had introduced and spread that deadly disease.¹⁰

In 1998, after carefully scrutinizing dead specimens from Australia and Central America, epidemiologists discovered a common killer. It was not a virus as Laurance had first suspected, but an exotic and previously unknown chytrid fungus, now named Batrachochytrium dendrobatidis (“Bd” for short).¹¹ They were then able to isolate Bd in dead frog specimens from across the globe. And when they exposed healthy laboratory frogs to the fungus, the same deadly symptoms rapidly appeared.

Having successfully isolated the Bd fungus and demonstrating its lethal effects, additional laboratory experiments soon explained why the world’s frogs were killed in locations with cooler temperatures, such as higher elevations. In the laboratory, Bd was virulent between 53° and 81°F (11.6 and 27°C). Its optimum growth occurred between 60° to 77°F (15.5 and 25°C), but the fungus also survived near-freezing temperatures. In contrast, temperatures over 86°F killed the fungus,¹² which explained why populations of the same species living in warmer habitats were surviving, and why outbreaks were more common in winter than in summer. Furthermore they demonstrated that the fungus depended on a moist environment and died after drying. That explained why Monteverde’s stream-dwelling frogs were extirpated, but Tink frogs living in drier habitat thrived.

African clawed frogs were identified as carriers and are immune to the disease. They had been imported around the world for embryological research and pregnancy testing. The mechanisms by which the fungus is spreading have not been fully elucidated, however bull frogs are immune and carry the diseases were being introduced throughout the tropics as a food source. The pet trade and educators often relocate amphibians, and the fungus can cling to the boots of researchers and tourists. Indeed it appeared that the best studied populations were the most devastated. Once the pathogen had been identified, I expected an educational campaign to limit the chytrid’s deadly spread, but top journals like Nature continued to push only the climate hypothesis.

In 2013, infected African clawed frogs were found in the ponds of San Francisco’s Golden Gate Park surrounding the California Academy of Science, and native species had been exterminated. Fifteen years after this devastating disease was first diagnosed and likely carriers identifed, there has yet to be a public education campaign largely due to the competing claims that global warming was the agent of death.

In contrast to the scientific rigor of the epidemiologists, Alan Pounds and the journal Nature actively campaigned to down-play the disease hypothesis and blame CO₂-caused warming to incite public fears of climate change. Pounds’ earliest research had correctly warned that the disappearance of amphibians at Monteverde was not just a natural cycle of boom and busts. However in 1999, despite the discovery of Bd and despite contradictory climate evidence, Pounds began pushing global climate change as Monteverde’s great amphibian killer. Publishing in the journal Nature he argued, “The changes are all associated with patterns of dry-season mist frequency, which is negatively correlated with sea surface temperatures in the equatorial Pacific.” He continued, “This hypothesis builds on evidence that rising sea surface temperatures have altered the climates of tropical mountains.” He supported his climate argument by referring to Parmesan’s faulty Edith’s checkerspot butterfly studies and argued that increased evaporation from the oceans was “amplifying the warming in the highlands relative to the lowlands.”⁴ Unlike the scientific rigor demanded by Koch’s postulates the simple coincidence of an El Nino and an extinction readily elevated climate change as the causal front-runner for spreading disease. Thus began the battle of dueling extinction theories.

Flip Flops of Global Warming Advocates

“There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.”  Mark Twain- Life on the Mississippi

Pounds was not deterred by the fact that there was no drying trend in Monteverde’s annual, seasonal, or monthly rainfall. Nor was there any trend in the variability of day?to?day rainfall. However, after dissecting Monteverde’s weather data, he extracted a single statistic that correlated with increasing CO₂ levels. He calculated that during the normal dry season, from January to April, the number of “dry days” with only zero to 0.1 mm of mist had increased from about 12 to about 40 days. Pounds was splitting climate hairs. In fact, 0.1 mm is literally the width of a human hair, and a slight change in a summer breeze could easily alter any mist measurements. But such a simplistic correlation was all he needed to get published in the most rigorously peer reviewed journal Nature. Nature also published a supporting companion article by the late Dr. Stephen Schneider, who used a global climate model to create a futuristic scenario that if CO₂ doubled it “could” raise the clouds and “perhaps” cause a harmful drying effect.

But the mist argument was rapidly becoming irrelevant. Evidence from around the world was mounting that Bd was the worldwide killer, and Bd preferred cooler wet habitats. In grave contrast to Pounds’ emphasis on dry days and amplified heat, in reality, dryness and heat was protecting the frogs from the deadly disease.

So Pounds then argued that that those few extra dry days had weakened the frog’s immune system and set the stage for Bd infection. He argued that if his theory was correct then “widespread amphibian extinctions in seemingly undisturbed highland forests may attest to how profound and unpredictable the outcome can be when climate change alters ecological interactions.”⁴ But unlike the rigorous process demanded by Koch’s postulates, Pounds did not need to demonstrate how a few days of subtle changes in mist had exterminated a species inside a burrow. He did not need to prove how a species adapted to millennia of periodic El Niños was suddenly weakened by just 20 scattered days without 0.1 mm of mist. Yet CO₂ advocates uncritically embraced the climate change connection, and over 900 papers cited Pounds’ work, compared to the little more than 200 scientists who cited Laurance’s well-tested novel disease hypothesis.

Because there was no long-term instrumental climate data at Monteverde, a few scientists questioned if those underscored dry days were perhaps just part of a longer natural cycle. Experts from Columbia University’s Lamont-Doherty Earth Observatory analyzed tree cores around Monteverde and reconstructed the long-term temperature and moisture trends. They concluded, “There was no evidence of a trend associated with global warming.”¹⁴

Still Michael Mann heralded Pounds’ explanation in his book Dire Predictions, where he highlighted both the Polar Bears and the Golden Toad as his two biological examples of global warming’s catastrophic consequences. Nature and C.D. Thomas teamed up again to publish Extinction Risk From Climate Change¹⁶ writing “Climate change over the past 30 years has produced numerous shifts in the distributions and abundances of species and has been implicated in one species-level extinction,” referring to the Golden Toad. With nothing more than untested speculation, the Golden Toad became the poster child for extinction by CO₂–caused global warming, and Alan Pounds joined Camille Parmesan among a very small select group of biologists invited to serve on the Nobel-prize winning Intergovernmental Panel on Climate Change. Pounds’ “CO₂-caused-warming-caused-extinction” theory exemplified what Wunsch had warned against. Without a shred of supporting evidence, Pounds’ hypothesis dominated research and the media, based simply on forceful storytelling and a powerful advocacy journal.

Around the world, rapid amphibian die-offs continued and each extirpation consistently coincided with the sudden arrival of the Bd fungus. As the evidence for Bd mounted, evidence for Pounds’ link to global warming continued to weaken because high temperatures and dryness killed the fungus, and protected the frogs. So CO₂ advocates simply dubbed this the climate-chytrid paradox, and faced with ever-mounting contradictory evidence, Pounds changed the specifics of his global warming theory. No longer was the increased “number of dry days” or “amplified warming” the killer. Pounds now reported that Monteverde’s 25 year historical temperature record revealed an approximate 2°F decline in maximum temperature along with an approximate 2°F rise in minimums. So he proposed the chytrid-thermal-optimum hypothesis, in which daytime cooling and night time warming accelerated disease development.¹⁷

He now argued that a combination of declining maximum temperatures and an increase in cloud cover had shielded the infected frogs from the healing heat of the sun and was “fostering moist conditions.” He argued that sunlit mats of mosses can sometimes reach the 86°F (30°C) that was known to be lethal to Bd, and those sunlit mats would have served as healing zones to naturally kill the fungus if not for CO₂.¹⁷ However Pounds knew that the Golden Toads retreated to their dark burrows immediately after breeding and would never have visited those hypothetical “healing patches.”

Furthermore most of his published temperature trend occurred after the Monteverde extinctions. He also ignored earlier research documenting that the Golden Toads had always emerged from their burrows when their breeding pool temperatures were in Bd’s optimal range.¹⁵ If an optimal temperature was required to trigger the deadly disease, the frogs should have died decades earlier. Clearly, Pounds was manufacturing any possible link to rising CO₂ levels.

So Nature published Pounds’ more adamant connection to CO2 in “Widespread amphibian extinctions from epidemic disease driven by global warming”.¹⁷ Embodying the forceful storyteller Pounds boldly stated, “we conclude with ‘very high confidence’ (>99%, following the Intergovernmental Panel on Climate Change, IPCC) that large-scale warming is a key factor in the disappearances. We propose that temperatures at many highland localities are shifting towards the growth optimum of Batrachochytrium, thus encouraging outbreaks. With climate change promoting infectious disease and eroding biodiversity, the urgency of reducing greenhouse-gas concentrations is now undeniable.”¹⁷ To further promote this “new” climate optimum hypothesis, Nature added anther companion opinion piece singing the praises of Pounds’ “elegant idea”. Yet Pounds was absolutely wrong.

Other scientists suspected Pounds’ correlations with climate change were simply due to a lack of statistical rigor. In a 2008 paper, “Evaluating the links between climate, disease spread, and amphibian declines” the researchers demonstrated just how easy it is to generate meaningless statistical correlations. In response to Pounds’ link to global warming they wrote, “Numerous other variables, including regional banana and beer production, were better predictors of these extinctions. Almost all of our findings were opposite to the predictions of the chytrid-thermal-optimum hypothesis.”¹⁸

Clearly changing our carbon footprint will never, ever remove Bd’s preferred range of temperatures from the world. Some locations may be more optimal than others, but the world will always abound with regions experiencing 53° to 81°F (12-27°C), and wherever and whenever that range occurs, the fungus will grow and spread. Whether man-made or natural, the very most that climate change could ever do is shift the the season when Bd does it’s killing. It was the ease of modern day transportation, and uneducated people who assisted the global spread of disease carriers that allowed Bd to rapidly find new locations with acceptable climates. The best solution for conservationists was to use captive breeding wherever vulnerable species faced imminent extinction. But to protect the CO2 theory, Pounds and Nature unconscionably attacked this life-saving solution promoted to save the frogs.

Denigrating Conservationists

Fortunately, biologists trying to save the frogs understood the real danger and published elsewhere in journals not dominated by climate change advocacy. Seventy?six amphibian experts eventually agreed on an amphibian recovery plan, and set out to rescue species most likely to be endangered by the spreading wave of Bd fungus. They targeted regions where the climate suited Bd’s growth, and sought out regions nearest the latest wave of the disease’s advance (see map below). Their efforts have been overlooked by the media and advocacy journals, but their success is a tribute to the power of good science.

Reminiscent of the wave of introduced diseases brought by Conquistadors that extirpated millions of native Incas and Aztecs, Central and South American amphibians were under the attack of a rapidly spreading fungus. Karen Lips had been surveying amphibians in Central and South America and had tirelessly warned of the impending dangers of spreading Bd. In 2008 she reported, “Available data support the hypothesis of multiple introductions of this invasive pathogen into South America and subsequent spread along the primary Andean cordilleras. Additional analyses found no evidence to support the hypothesis that climate change has been driving outbreaks of amphibian chytridiomycosis”.¹⁹ Martha Crump, who had originally worked with Pounds analyzing the demise of the Golden Toad, now fully grasped the disease’s devastating potential. After the sudden appearance of Bd in Panama and the onset of mass die-offs, these biologists estimated the rate and direction in which the disease would spread. They predicted that the next wave of extinctions would soon strike El Valle, Panama and assembled a team of volunteers from Zoo Atlanta. They flew to Panama and airlifted 600 live frogs of potentially threatened species to safety just before Bd’s predicted arrival ravaged amphibian populations months later.

 

The hope now is that captive breeding will provide those species with the opportunity to evolve natural immunity, so eventually they can be released back into the wild. Fortunately, natural selection typically causes new virulent diseases to evolve into less deadly forms. If a strain of the chytrid fungus kills its hosts too quickly before the fungus can reproduce, it eliminates its most deadly genomes. On the other hand, because the disease kills the frogs that are the most vulnerable, any surviving frogs with more resistant genetics slowly repopulate their old habitat. Eventually, a balance evolves where more resistant amphibians and a less virulent disease coexist. Before the age of modern transportation, this evolutionary process happened within a limited area. However if a disease is spread around the world before a balance evolves, the most virulent forms spread a trail of tragic consequences. Species with small populations in a restricted habitat, like the Golden Toad and relatives of the Harlequin Frog, are most vulnerable. A single introduction of the disease can rapidly wipe out an entire species.

In 2012 researchers in the Sierra Nevada also documented a wave of extinction as the fungus’ spread through three lake basins around Sequoia National Park. Only after the fungus suddenly appeared did the local frogs go extinct. These experts again found no support for the Pounds’ global warming hypothesis.²² So much for Pounds’ forceful storytelling and his “very high confidence” (>99%, following the Intergovernmental Panel on Climate Change) that global warming was the driver of amphibian extinctions.

Lips’ valiant attempts to prevent extinction threatened Pounds and his followers and he published articles attacking those conservation efforts. In the journal Science, Pounds denigrated the airlift efforts, “To suggest that this alone can halt the extinctions undermines scientific credibility and engenders false hope and complacency among voters and consumers. Biodiversity loss warns that humanity’s life-support system is crumbling. Those who realize this may become responsible global citizens, demanding sound governance and accountability.”²⁰ Pounds and his fellow advocates appeared less worried about saving frogs and more concerned about maintaining a climate of fear and its political leverage.

For those interested in the scientific detective work that unraveled the Bd epidemic, I highly recommend the 2009 book Extinction in Our Times: Global Amphibian Decline, coauthored by Pounds’ old colleague from Monteverde, Martha Crump. Because Crump sang the praises of the researchers whose tireless efforts identified the spreading disease, the journal Nature and Pounds now teamed up to discredit the book and discourage readers.

Pounds wrote, “James Collins and Martha Crump try to reassure us that these vanishing creatures are not warning of large?scale environmental deterioration like canaries in a coal mine, but are simply telling us that they themselves are in trouble. A book blaming a fungus for the disappearance of amphibians from wild places wrongly downplays the role of environmental change.”²¹ But Collins and Crump had most definitely stated that in addition to the fungus-caused deaths, scientists must counteract the other factors threatening the environment. They wrote, “We now recognize commercial exploitation, introduction of exotic species, and land use as ongoing causes of amphibian declines”. But that was not the “environmental change” that Pounds and Nature were trying to exploit. They hijacked a disease transmission issue to wanting us to believe “humanity’s life-support system is crumbling” solely due to rising levels of CO₂.

The rapid spread of the chytrid disease still continues worldwide. Although powerful journals like Nature and Science advocated Pounds’ climate hypothesis and persistently maligned the disease hypotheses, and funds were continuously diverted to test Pounds’ ever-changing climate hypotheses, only Laurance’s 1996 hypothesis of a rapidly spreading novel disease has stood the test of time, simply because it was based on rigorous science. Although no carcass of a Golden Toad was ever found and examined, all evidence pointed to Bd, as the first arrival of the fungus correlated with their sudden disappearance.

Nonetheless in 2011, Nature published another article by Camille Parmesan who urged we end the climate debate, “By over-emphasizing the need for rigorous assessment of the specific role of greenhouse-gas forcing in driving observed biological changes, the IPCC effectively yields to the contrarians’ inexhaustible demands for more ‘proof’, rather than advancing the most pressing and practical scientific questions.” Then, as if science had ever proven that CO₂ had killed the Golden Toad she wrote, “Species’ extinctions have already been linked to recent climate change; the golden toad is iconic.”²³

Indeed, the Golden Toad is iconic. It is iconic of repeated attempts to link rising CO₂ to spreading diseases and extinctions based on unsupported correlation and non?existent evidence. It is iconic of repeated attempts to evoke a climate of fear at the grave expense of sincere conservation efforts. Understanding how modern transportation enhances the transmission of this deadly fungus and other diseases like SARS and influenza is “the most pressing and practical scientific question,” and blaming CO₂ warming has been the biggest distraction.

To push a political agenda politicians eagerly capitalize on every tragic event and the Golden Toad demonstrates why public debate about climate change and “demands for proof” are more important now than ever. That is the real scientific process. The case of the Golden Toad exemplifies the methods of Parmesan and Pounds and Mann who represent the illusory “97% consensus” whose authority we are repeatedly told we must never question.

The giants of history like Darwin’s “bulldog” Thomas Huxley relentlessly urged greater critical thinking arguing, “Every great advance in natural knowledge has involved the absolute rejection of authority.” And Benjamin Franklin rallied, “It is the first responsibility of every citizen to question authority.” In contrast advocate scientists and their followers like David Suzuki and Mark Hertsgaard try to bully the media if the media presents any views skeptical of the consensus’ manufactured authority. Their insistence on “denying the deniers the right to deny” uses fear mongering like the Golden Toad’s extinction and every human tragedy to promote an intellectual tyranny. Such tactics are far more dangerous to our way of life than the current levels of CO2. We must demand more public debates between skeptics and advocates that are honestly moderated, so the world can separate good science from the bad.

Adapted from the chapter "Beating Dead Frogs with CO2"  in Landscapes & Cycles: An Environmentalist’s Journey to Climate Skepticism by Jim Steele

Literature Cited

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