The Truth About Climate Change

By Andrew Bernstein

Climate change is real and persistent. Even a brief study of the recent past illustrates this, but it becomes all the more certain when one broadens the scope to take in the vast sweep of geologic time.

Is nature’s inherent dynamism responsible for the climate change of our era? Or are the cause(s) man-made?

Many scientists, environmentalists, journalists, and such politicians as Al Gore claim the latter.

They argue that:

  1. The earth is warming.
  2. Human emission of such greenhouse gases as CO2 is the predominant (perhaps exclusive) cause.
  3. Such warming, in various forms, is pernicious to life on Earth, including human life; for example, increasing temperatures may melt the land-based polar ice caps, thereby causing rising sea levels that will flood low-lying coastal regions.

This is known as the theory of man-made or anthropogenic global warming (the AGW hypothesis). The public policy questions that arise are profound, and the stakes are high; for if the AGW hypothesis is true, then we aren’t doing enough to protect ourselves from baneful consequences.

But if  the AGW hypothesis is mistaken regarding either points two or three—much less both—then a dramatic scale-back of man-made carbon emissions is an insane policy that will severely diminish human living standards while promoting no off-setting gain.

The Intergovernmental Panel on Climate Change (IPCC)—a group of scientists under United Nations jurisdiction—supports the AGW hypothesis. Its proposed solution is a dramatic increase in government power to impose massive scale-backs in the use of carbon based fuels.  Such a policy would affect the price and availability of literally everything we own: our clothes, home, food, medicine, and means of transportation. Energy powers civilization; the less of it produced, the more difficult and poverty-ridden life becomes.

Needlessly diminishing carbon-based energy production without a viable alternative will have drastic consequences in the developed world. But more harrowing, it will mean certain death for millions of people in the undeveloped world. The first point to be established, therefore, is whether, in fact, there is any rational basis for accepting the AGW hypothesis. Doing so requires an understanding of Earth’s climate history viewed in the proper context, meaning in this case, on an appropriate timescale.


Earth’s Climate Over Geologic Time

Charts are a common part of contemporary climate change debate. It is frighteningly common to see charts that graph out as much as the last 150 or so years of climate history. During that time, the Earth, on average, warmed roughly 2.16 degrees Fahrenheit (approximately 1.2 degrees Celsius). Our era, consequently, is known as the Modern Warm Period. This truth is widely acknowledged by scientists.

Those that refuse to evaluate climate change on the proper timescale present this as a fair sample of the Earth’s climate trajectory. Given the human life expectancy, there is even some plausibility to such a narrow time frame. That is, until we are reminded that the Earth is approximately 4.5 billion years old. That puts the sample  examined at a nanoscale percentage of Earth’s climate history. It is like straining to read a billboard when able to view but a single pixel of it.

What AGW theorists fail to mention is that the Earth in our day is significantly colder than it has been through much of its voluminous history. For the past 50 or so million years, the Earth has been gradually cooling. Prior to that, our planet had been substantially warmer. Fossil remains of tropical flora and fauna, for example, have been found north of the Arctic circle, and crocodiles lived in these northern climes.[1] It was around 30 or 35 million years ago that global temperatures dropped sharply, leading first to Antarctic glaciation, then (millions of years later) to Arctic ice sheets, and eventually to the Pleistocene Ice Age, including the most recent wave of Northern Hemisphere glaciation. Before then, Earth’s vast history—although interspersed with severe ice ages—featured climates generally warmer than today’s. Geologist, Dr. Doug Macdougall, notes, “On average, for the past few million years, the Earth has been considerably colder than over most of its four and a half billion years of existence.”[2]

Indeed, the geology professor points out that, “During much of Earth history, except for short, rare intervals, glaciers such as the one on [Mount] Kilimanjaro have been absent.”[3] Does this mean that for much of Earth’s vast history the planet has been too warm for substantial accumulations of ice? Evidently it does.

If ice ages are unusual features of Earth’s history, such rarity does not mitigate their severity. One such extreme episode, nicknamed “Snowball Earth,” occurred between 800 million and 600 million years ago, featuring at least two and possibly four or five recurring waves of ice ages so severe that the entire planet, pole to pole, including the tropics, perhaps even the oceans, were heavily glaciated.[4]

By 540 million years ago, the Earth had transformed from a giant snowball (or slushball, as some scientists prefer) to a warm, humid world propitious for the development of diverse life forms. Such a hospitable climate helped precipitate the “Cambrian Explosion” of living organisms, a period during which the ancestors of most major animal groups appeared in the fossil record for the first time.[5]

The period from about 300 million to 280 million years ago saw the Earth once again in the deep freeze—in the harshest years of the Permo-Carboniferous Ice Age; one whose severity exceeded that of the later Pleistocene glaciation. There was one supercontinent on Earth then, referred to by geologists as Gondwanaland. It was only later that the continents split and drifted apart; and across the Gondwanaland supercontinent the fossil record shows the baneful impact on plant life of the Permo-Carboniferous glaciation; only the hardiest breeds survived.[6]

Around 250 million years ago the Earth was again hot but now so dry that huge salt deposits formed from the evaporation of sea water.[7] Fast forward some 150 million years to approximately 100 million years ago, and the Earth was still uniformly hot but humid again, and dinosaurs roamed its surface as the dominant land vertebrates.[8]

Moving closer to our day, by 55 million years ago the Earth sweltered under the blazing heat of the Eocene Thermal Maximum, when global temperatures increased by approximately 9–10.8 degrees Fahrenheit (roughly 5–6 degrees Celsius), with perhaps even more pronounced warming in the Arctic region.[9] Widespread extinctions were associated with this “heat wave” lasting approximately 100,000 years, but the ancestors of many of Earth’s current life forms survived.[10]

Additionally, throughout geologic time we find numerous examples of non-cyclical but, rather, sudden and catastrophic natural climate change.


Catastrophic Climate Change

The geological record indicates five major mass extinctions during the past 450 million years.

The causes are disputed. Renowned geologist, Dr. Tony Hallam, describes several leading theories. One, that of bolide impact—the collision of comet or asteroid with the Earth—is today widely believed to have provided the coup de grace to dinosaurs, life forms already, at that time, dying off after 165 million years as Earth’s dominant land vertebrates.[11] The land impact of a high-speed bolide would inject into the atmosphere an immense dust cloud that could envelop the Earth for perhaps up to a year. As Hallam states regarding this purported cause of the end-Cretacean mass extinction:  “Such a cloud would have blocked out sunlight, thereby stopping photosynthesis and resulting in a collapse of the food chain, with consequent starvation and mass extinction.”[12]

Evidently, the Earth has suffered through perhaps a dozen of these massive collisions in its history, destroying millions of life forms whose existence we know of only via the fossil record. Climate scientist, Dr. Fred Singer, writes of them:  “The Earth’s collisions with massive missiles from outer space explode billions of tons of ash and debris into the Earth’s atmosphere, darken the skies, and virtually eradicate the growing seasons for years at a time.”[13]

Another candidate that could potentially wreak major extinction is volcanic activity. A relatively recent example of the baneful global reach of volcanic activism was the Tambora eruption on the Indonesian island of Sumbawa in April 1815. Gillen D’Arcy Wood, in his study of Tambora’s destructive consequences, writes of “the cascading worldwide weather disasters in its three-year wake.”[14]  Part of the problem, Wood says, is “the sun-blocking dust veil …[which] might linger above the earth for up to three years.”[15]  Perhaps worse is the release of gaseous sulfur compounds that rise into the stratosphere, where they combine with the limited water available to form droplets of sulfuric acid; these droplets reflect a substantial amount of sunlight away from the Earth and back into space—and can cause significant global cooling for up to two years.[16]

The lead candidate for causation of the end-Triassic mass extinction—that expunged approximately twelve percent of the planet’s vertebrate families—is a series of massive volcanic eruptions in Brazil, the east coast of North America, Morocco, and Spain.[17]

Related, paleobiologist , Dr. Douglas Erwin, the leading authority on the end-Permian catastrophe that wiped out approximately ninety-five percent of Earth’s life forms,  credits on-going eruption of Siberian flood basalts as the likeliest cause. The massive quantity of dust spewed into the atmosphere could lower temperatures for years; but worse would be the conversion of sulfate aerosols to sulfuric acid, then to be poured down as acid rain. Combine these and other factors, says Erwin, and the result is horror that only Dante could adequately describe.[18]

Hallam also points out other possible causes of mass extinctions, such as severe climate change, especially pronounced cooling periods.[19]

One conclusion is abundantly clear: The power of nature—whether via bolide impact, massive volcanism, and/or other causal agents—to wreak sudden cataclysms inflicting both widespread climate change and massive devastation of life borders on the indescribable.

But cyclical—not fitfully irregular—climate change is most relevant to understanding the warming of our era.


The Pleistocene Ice Age

Although it is today not widely discussed, the Earth is currently basking in the relatively higher temperatures of an interglacial warm period—known as the Holocene—of the on-going Pleistocene Ice Age. In contrast to modern hysteria regarding global warming, a great deal of geologic evidence points towards the return of thick Northern Hemisphere glaciers within the next 1,000 to 10,000 years.[20] Macdougall writes, “It is often not appreciated that today’s climate is just a geologically short warm spell in this continuing ice age.”[21]

Roughly 30 million years ago, ice sheets formed and expanded in Antarctica. These were followed by extensive glaciation in Greenland approximately 18 million years ago. Then perhaps just under 3 million years ago glaciers moved into North America. Over the past 2-3 million years, the Northern Hemisphere has seen repeated cases of extensive glaciation—and of thick ice sheets extending well into northern portions of what is today the United States.[22] Indeed, the sites of cities such as Montreal and Chicago were buried beneath ice sheets perhaps thousands of feet thick.[23]

Over the past million years, the recurring Northern Hemisphere ice ages have occurred on 100,000 year cycles. These include roughly 80,000 to 90,000 years of colder climate and advancing ice interspersed with roughly 10,000 to 20,000-year interglacial periods of warmer climate and retreating ice.

There are also cycles within climate cycles. About 12,500 years ago, the latest wave of Northern Hemisphere glaciation began, lasting for roughly 1000 years—until about 11,500 years ago, when northern regions warmed suddenly from ice age conditions to almost current temperatures.[24] The past 11,500 years, continuing to our day, make up the Holocene interglacial warm period—a relative warm spell in the midst of what is still one of Earth’s colder periods: the Pleistocene Ice Age. The bad news is that, measured in terms of geologic time, if the Earth’s history is an accurate guide, glaciers will soon return to more southerly latitudes of the Northern Hemisphere.[25]


The Past Millennium

As part of this on-going cycle there have been numerous other periods, leading up to our own day. One, the Medieval Warm Period (roughly 900–1300 AD) saw temperatures in the Northern Hemisphere approximately as warm as they are today,[26] enabling the Norse to colonize both Iceland and Greenland, the English to plant grapes and establish vineyards, the Norwegians to harvest crops at higher elevations than for a millennium and the Scots at elevations higher than today.  Across Europe, higher temperatures contributed to crop yields more robust than in the colder period that ensued.[27] Wine was produced in northern European climes that today are too cold for growing grapes, indicating that northern temperatures might have been 1 to 1.4 degrees Celsius (roughly 1.8 to 2.5 degrees Fahrenheit) warmer than at current times.[28]

Following this was the Little Ice Age (roughly 1300-1800). We know that temperatures in Europe, the North Atlantic, and North America were generally cooler than today. Alpine glaciers advanced, encroaching on farms and human habitations. The Norse were forced by harsher climate to abandon their earlier Greenland settlements. Inuit peoples in the Arctic region began migrating south. In parts of Germany, Holland, and Denmark, the fierce storms associated with colder weather destroyed large swathes of agricultural land, leading to widespread famine.[29]

During the depths of the cold temperatures, in the 1690s, crops were widely devastated. As a result, tens of thousands (of a total population under 2 million) starved to death during the so-called “Lean Years” in Scotland.[30] Even more disastrous, during the same decade, in Finland, famine wiped out twenty-five to thirty-three percent of the country’s entire population. A leading historian terms it “the most terrible event in European history.”[31]   In the past several thousand years, there have been other eras of naturally-cycling climate change, as well. [32]

The above data regarding the Earth’s swings between colder and warmer periods is sufficient to establish an important conclusion: Cyclical natural climate change has been a regularly recurring feature of the Earth across both geologic and more recent times.

Subsequent to these climate eras, from approximately the late-nineteenth century until our day, the Earth warmed slightly—by roughly 2.16 degrees Fahrenheit (approximately 1.2 degrees Celsius). John Houghton, a professor of atmospheric physics at Oxford University, a co-chair of the IPCC’s scientific assessment working group, and lead editor of the first three IPCC reports, writes that, in the past several decades, minimum temperatures over land have increased approximately twice as much as have maximum temperatures. Further, Houghton reports that, because of the warming, global mean sea levels during the twentieth century increased at an average annual rate of 1–2 millimeters, Arctic sea-ice extent and thickness thinned by forty percent in recent decades during months of late summer to early autumn, non-polar glaciers during the twentieth century retreated substantially, and growing seasons in the Northern Hemisphere lengthened by about one to four days.[33]  Our era, consequently, is known as the Modern Warm Period.   

It should be perennially remembered that the various proxies described above indicate that Northern Hemisphere temperatures during the Medieval Warm Period–centuries before initiation of human industrialization–were slightly higher than during our day.



The Necessity to Affirm, Not Deny Climate Change

Notice further that there are cycles within climate cycles. For example, as Dr. Macdougall points out, for approximately the past 50 million years the Earth has been gradually cooling. But, during the Roman Warm Period, the Medieval Warm Period, and the Modern Warm Period, the Earth warmed. Further, even within the Modern Warm Period there have been cycles; for example, although the Earth generally warmed from the late-19th century to today, there was, in the midst of this warming, a cooling trend from approximately 1940 to 1975,[34] resulting in Newsweek’s now-infamous 1975 article fretting about a possible looming ice age.[35] Amidst all of this is the on-going 2-million-year Pleistocene Ice Age, with its recurring cycle of glaciations followed by milder inter-glacial warm periods.

Any rational human being, examining the above facts, must affirm the reality of climate change. Indeed, we must so strenuously affirm its reality that we feel compelled to raise the eminently logical and too-infrequently asked questions:  Is the Earth’s climate always changing?

Is there ever a time when Earth’s climate is not changing?

Is climate but one more instance of the incessantly dynamic nature of the physical world? From the instant a living being is born, for example, is there ever a moment when it is not aging? Does the Earth stop momentarily in its rotation—so that there is a break in the day/night cycle—or does it whirl relentlessly on? Does our planet ever cease revolving around the sun, thereby disrupting the pattern of the seasons, or does it forge ceaselessly forward? The erosion of mountains to molehills, as a final example, is a process so agonizingly slow that the resulting disparity in stature reveals the inexorability of wind, rain, and storm, forces never granting the exposed peaks a moment’s respite.

Two millennia ago, the Greek philosopher, Heraclitus, observing the ubiquity of process in the natural order, theorized that change itself—activity or dynamism—is the fundamental reality, rather than entities that, in various forms, undergo change; a logical error brilliantly corrected by Aristotle. Both thinkers, however, were deeply impressed by the robust dynamism of the empirical world.

Is climate any less dynamic than these other processes of nature? There is no logical reason that it should be—and a great deal of empirical data suggests that it is not. Indeed, the IPCC itself, in its 2001 report, acknowledged: “Climate has always varied on all time scales…”[36]

This point can be summarized succinctly: Climate is often changing; probably generally changing; perhaps always changing.

It is precisely this context, an appropriate timescale, that many (if not all) AGW theorists ignore. A stockbroker, who tried to convince investors to buy a stock based on its performance in the last sixty seconds, while blanking out decades of data, would be ignoring vastly less relevant information than do the majority of today’s supporters of man-made global warming.

The accusation of “climate change denier” is, consequently, egregiously inaccurate when hurled at persons who examine this context and recognize the reality of natural, cyclical, and likely incessant climate change.

The accusation is accurate, however, when leveled against some leading supporters of the AGW hypothesis. Dr. Michael Mann, for example,  a respected climate scientist and lead author for the IPCC, developed the infamous “hockey stick” graph, purporting to show that, for roughly 1,000 years prior to the 20th century, Northern Hemisphere temperatures had been relatively stable, perhaps even declining slightly, then sharply rising after 1900 (hence the hockey stick shape of the graph). In effect, Mann’s methodology “air-brushed” out of existence the Medieval Warm Period; if accurate, Mann’s findings would show a strong and unique correlation between human emissions of carbon dioxide and rising temperatures. However, Mann’s methodology was seriously flawed and exposed as such by Dr. Edward Wegman, a leading statistician. The hockey stick graph, a featured aspect of the IPCC’s 2001 report, was subsequently dropped by the IPCC. The Medieval Warm Period had to be acknowledged as real.[37]

But Mann, some of his IPCC colleagues, and the environmentalist movement more broadly continue to support the hockey stick hypothesis.

According to Mann and his supporters, Northern Hemisphere temperatures were relatively flat for roughly 1,000 years, and the natural climate cycles from the Dark Age Cold Period to the Medieval Warm Period to the Little Ice Age were non-existent (or, at most, greatly over-exaggerated).

Who, then, is actually guilty of denying climate change?[38]

Nevertheless, even when recurring natural climate cycles are recognized, an important question can and must be raised: What is the relationship between ongoing climate change and human activity?



The AGW Hypothesis—And Its Flaws

There is, in truth, a greenhouse effect, for which we all should be grateful; for without it, the Earth would be too cold to support life. Carbon dioxide is indeed a greenhouse gas, serving to trap heat near the Earth’s surface, contributing to rising temperatures. The late paleontologist, Dr. Robert Carter, stated the facts simply: It is, he says, an established physical property of carbon dioxide that it “absorbs space-bound infrared radiation, thereby increasing the energy available at the Earth’s surface for warming or increased evaporation.”[39]

Since the Industrial Revolution, human beings have pumped increasing amounts of carbon dioxide into the atmosphere. At the beginning of the Industrial Revolution, for example, scientists believe that the atmospheric concentration of CO2 was around 280 parts per million (ppm). By 1958, it stood at approximately 315 ppm. Today, it stands at just over 400 ppm.[40] Since the mid-nineteenth century, Earth’s temperature has also risen. Therefore, there is both an established physical mechanism by means of which CO2 contributes to increased warming—and a very rough correlation over the past 150 years between rising atmospheric accumulation of CO2 and rising temperatures.

Does all this support the conclusion that man-made CO2 is the predominant, perhaps exclusive cause of modern warming?  

There is, among several others, one very inconvenient truth for AGW theorists. For at least the past 240,000 years, Earth’s warming has preceded rising CO2 levels, not vice versa. Analyses of ice cores from Antarctica’s Vostok Glacier, for example, reveal that over the Earth’s past three glaciations and ensuing warmer periods, rising CO2 levels lag behind rising temperatures by several centuries.  Oregon State Climatologist, George Taylor, stated, “In other words, CO2 changes are caused by temperature changes.”[41]

Israeli astrophysicist, Dr. Nir Shaviv, commented: “In all cases where there is a good enough resolution, one finds that the CO2 lags behind the temperature by typically several hundred to a thousand years. Thus, the basic climate driver that controls the temperature cannot be that of CO2.”[42] Dr. Robert Carter concurred: “The ice core data show conclusively that, during natural climate cycling, changes in temperature precede changes in carbon dioxide by an average 800 years or so.”[43] Climate scientist, Dr. Fred Singer agrees: “Global warming has produced more CO2 rather than more CO2 producing global warming.”[44]

Notice further that, during the Modern Warm Period, the correlation between atmospheric build-up of CO2 and rising temperatures is inexact.  Dr. Singer points out: “Most of the current warming occurred before 1940,” prior to a large accumulation of man-made CO2 in the atmosphere.[45] Then, between 1940 and 1975, in the post-World War II period, booming industrialization injected large amounts of CO2 into the atmosphere while the Earth cooled.[46] Finally, early in the twenty-first century, CO2 concentrations have shot up to 400 ppm but, when naturally-occurring El Nino effects are subtracted from the data set, there has been no measurable warming since 1998. Dr. Richard Lindzen, professor of atmospheric physics at MIT, a former lead author for the IPCC, and one of the world’s most eminent climate scientists, is but one of many scientists who point out this pause in warming.[47]

The full truth is that increasing accumulations of atmospheric CO2 is a cause of warming, but is merely one factor of many inducing climate changes—and is often overwhelmed by other, more powerful causes.[48] One example of this occurred about 440 million years ago, during the Ordovician Ice Age, when atmospheric accumulations of CO2 were 10-17 times higher than today’s and yet the Earth was in the depths of a severe glaciation.[49]

Part of the reason that CO2 is a weak cause of warming is that it is a trace gas in Earth’s atmosphere. Today, CO2 stands at 400 parts per million, meaning that 999,600 parts per million of the atmosphere are composed of other gases—78 percent nitrogen, 21 percent oxygen, and 1 percent trace gases, one of which is CO2. CO2 constitutes but four one-hundredths of one percent of Earth’s atmosphere. Expressed as a percent, CO2 constitutes merely 0.04 percent of the atmosphere; meaning that 99.96 percent of Earth’s atmosphere is constituted by gases other than CO2. Such a minute component of our atmosphere possesses neither the presence nor the power to cause substantial, much less catastrophic warming.

So, if over the past several hundred thousand years increasing CO2 levels have not driven rising temperatures, then what has?

A clue is that, in recent years, Mars has also warmed.[50] Eminent Russian astrophysicist, Dr. Habibullo Abdussamatov, head of the Space Research Laboratory at St. Petersburg’s Pulkovo Astronomical Observatory, says simply, “Mars has global warming, but without a greenhouse and without the participation of Martians.”[51]

Is there a positive relationship between the warming of two different planets in our solar system? Do these two warmings share a common cause?



The Sun-Climate Connection

Dr. Abdussamatov believes the warming of both planets is caused in part by cycles in the Sun’s overall power. Long-term increases in total solar irradiance (TSI) are a primary cause in a complex system that leads to global warming, here and elsewhere. He says: “The predominating factor influencing climate changes (geophysical effects lasting for decades) is alterations in a general two-century-long cycle of solar activity defined primarily by corresponding changes in TSI.”[52]

Between 1978 and 2003, the Sun’s radiation increased by nearly 0.05 percent per decade.[53] The Sun’s output is so immense that even such a small increase is equal to the full amount of human energy use.[54] Unsurprisingly, this was a period of general global warming.

However, such small differences in TSI are, in themselves, insufficient to account for either Earth’s most recent warming or for its repeated warming and cooling cycles. The Sun’s cycles may trigger the recurring changes in climate but some terrestrial process(es) must amplify the effect. Which process(es)?

Before answering this question, it is necessary to make a cognate point: Regarding one important relationship, there is little mystery. Scientists have long known that the oceans store vast quantities of CO2; indeed, the oceans contain roughly 50 times as much CO2 as does the atmosphere.[55] When the Earth warms, the oceans release greater amounts of CO2 into the atmosphere. States Dr. Abdussamatov: “If the temperature of the ocean rises even a little, gigantic amounts of CO2 are released into the atmosphere through the evaporation of water…. It is no secret that increased solar irradiance warms Earth’s oceans, which then triggers the emission of large amounts of carbon dioxide into the atmosphere.”[56]

But what are the terrestrial processes that amplify the effects of increased TSI, leading to global warming? One, discovered by leading Danish astrophysicists, Dr. Eigil Friis-Christensen and Dr. Henrik Svensmark, involves cosmic rays and the previously-little-understood process by which clouds are formed.[57] Meteorologists have long known that low-lying cloud cover helps keep the Earth cool, but they did not understand the causes of clouds. In 2006, Svensmark and his team permitted naturally occurring cosmic rays to filter in through their laboratory ceiling and interact with the chemistry of the lower atmosphere they’d replicated in the lab. “What they found left them agape: A vast number of floating microscopic droplets soon filled the reaction chamber. These were ultra-small clusters of sulfuric acid and water molecules—the building blocks for cloud condensation nuclei—that had been catalyzed by the electrons released by the cosmic rays.”[58]

They established that cosmic rays (energy released by exploding stars, i.e., super-novae) enter Earth’s atmosphere and release electrons in the air. These electrons encourage “the clumping of molecules to make micro-specks, capable of gathering into the larger specks needed for cloud formation.”[59] Svensmark’s team had identified a physical mechanism by means of which cosmic rays effectuate Earth’s cloud cover.

Dr. Eugene Parker, one of the world’s most accomplished astrophysicists, discoverer of the solar wind, wrote about Svensmark’s breakthrough: “It is our good fortune that, some years ago, Henrik Svensmark recognized the importance of cloud cover in the temperature control of planet Earth. Clouds are highly reflective to incoming sunlight. Svensmark also recognized that the individual water droplets that make up a cloud form mostly where ions have been created by passing cosmic ray particles, thereby tying cloud formation to the varying cosmic ray intensity. That is to say, cosmic rays control the powerful ‘cloud valve’ that regulates the heating of the earth.”[60]

When the Sun emits greater amounts of radiation, its magnetic field is strongest. This bolstered magnetic field protects Earth from cosmic ray bombardment. Fewer cosmic rays mean less clumping of molecules, which means formation of fewer low-lying clouds. The Sun’s increasing TSI directly accounts for only a small percentage of Earth’s rising temperatures. But the inhibiting of cooling cloud cover accounts for a good deal more.[61]

Celestial events and relationships can also explain the Earth’s cooling. The Earth’s elliptical orbit around the Sun is eccentric; the shape of the orbit at times is more elliptic, at times less. Therefore, the Earth’s farthest remove from the Sun is not uniform. Sometimes its greatest orbital extent from the Sun is more distant than at other times. Additionally, the Earth’s tilt on its axis varies between roughly one degree less than its current 23.5 and one degree more.  Finally, the Earth wobbles on its axis so that the direction of the Earth’s tilt varies over time; at times the Northern Hemisphere will, in effect, “lean” toward the Sun and at other times away  from it.[62]

All of these factors are cyclical, known today as “Milankovitch Cycles,” after Serbian mathematician, Milutin Milankovitch, who put the theory on its modern footing.[63]  When: 1. The Earth is at its farthest remove from the Sun at the same time that 2. The Northern Hemisphere “leans” away from, rather than toward, the Sun and 3. The Earth’s angle of tilt on its axis causes the Northern Hemisphere “lean” to be at its maximal point, at these times the Northern Hemisphere will receive its least amount of solar radiation and suffer through its coldest winters and coolest summers.[64]

These three astronomical factors align roughly every 100,000 years—which corresponds almost exactly to the Northern Hemisphere glaciations of the past two million years. Geologists consider such correspondence unlikely in the extreme to be coincidence.

But again, the change in solar radiation reaching the Earth is too slight in itself to cause significant change in terrestrial temperatures; amplifying factors are necessary to cause the plunge into an ice age. Scientists believe there are several. One is that decreased solar irradiance means colder winters and the likelihood of increased snowfall, including at more southerly latitudes—and cooler summers during which will occur diminished melt. Increased surface snow and ice reflect away more sunlight from the Earth’s surface, contributing to a downward temperature spiral. Scientists believe there are other contributing factors, as well. One is that greater disparity of temperatures between the polar region and the equator will increase winds, which would affect ocean currents, resulting in diminished heat carried northward by the Gulf Stream. It is also possible that increased wind intensity will carry more moisture northward from the tropics, causing increased precipitation, which, in those temperatures, will mean more snow fall.[65]

The specific terrestrial processes by means of which diminished solar radiance gets translated into conditions sufficiently cold for an ice age are not yet fully understood. But two important points are clear: 1. The underlying cause of the Pleistocene’s recurring waves of glaciation is the complex relationship between the Earth and the Sun 2. Diminished solar irradiance triggers a series of terrestrial processes that, taken in concert, substantially drive down temperatures.

No doubt there are further complexities regarding the Sun’s various recurring cycles and the processes by which greater and lesser amounts of solar radiation similarly get amplified into earthly climatic effect. But, as Dr. Singer argues, there is a striking long-term correlation between the Sun’s emission of radiation and Earth’s climate that simply cannot be overlooked.[66] Dr. Singer displays a graph charted by astrophysicists, Dr. Sallie Baliunas and Dr. Willie Soon, showing the correlation between solar irradiance and Earth’s Northern Hemisphere temperatures during the period between 1750 and 2000, a full 250 years. The temperatures, through wide and dramatic variations, track closely to the Sun’s emission of radiation. As Dr. Singer notes, “Given the variability of the temperatures, the close relationship between the two is startling.”[67]

Unfortunately, if the Sun-based climate theory is accurate, the Earth is heading toward a cooling period. Dr. Abdussamatov maintains that, “Solar irradiance has begun to fall, ushering in a protracted cooling period beginning in 2012-2015. The depth of the decline in solar irradiance reaching Earth will occur around 2041. . . . and will inevitably lead to a deep freeze around 2055-60.”[68]

Indeed, given the absence of (non-El Nino-induced) measurable warming over the past 15-18 years, the Earth’s cycle from warmer to cooler periods may have already begun.


Important Final Points

Man’s earliest ancestors evolved approximately 6 million years ago; the Homo group, including sapiens, arose perhaps 2 million years ago; and our species was distinguished roughly 200,000 years ago.[69] Therefore, cyclical climate change pre-dates man by, at minimum, hundreds of millions of years. 

Forces of nature are vastly more powerful than the forces of man. Can we retard a hurricane, for example, bearing down on our shores?  Smother massive volcanism from spewing millions of tons of ash, grit, and dust into the atmosphere, blackening the skies and blocking the sun? Impede an advance of northern glaciers poised to scrape human habitations from their current locales and deposit them, as twisted wreckage, hundreds of miles to the south?  We cannot.

Forces of nature have long—perhaps always—caused cyclical climate change. These changes—such as ice ages and their cessation—involve temperature swings vastly more dramatic than the mild warming of our era.

Astronomical factors are responsible for the cycles of the Pleistocene Ice Age. Are we to suppose that human emission of carbon dioxide is sufficiently powerful to bring down upon the Earth an equivalent ice age—or its melt? The Sun can do this. Man cannot.

Additionally, the best proxy data we have indicates that over geologic time Earth’s temperature  range has varied from roughly 50 degrees to 72 or 73 degrees Fahrenheit (10 degrees to 22 or 23 degrees Celsius). The best estimate we have today is that the Earth’s temperature is currently in the range of 59-60 degrees Fahrenheit (roughly 15 degrees Celsius).[70] The Earth’s temperature is, by several degrees, currently nearer the cooler rather than the warmer end of its historic spectrum.

The Earth’s range over geologic time is one more data point showing nature’s power to cause temperature swings substantially greater than that of the Modern Warm Period.

Finally, we have seen some of the primary causal agents inducing Earthly change of climate:

  1. the Sun’s spatial alignment relative to the Earth
  2. the Sun’s cycling in its emission of radiation
  3. cosmic ray bombardment of Earth’s atmosphere, actuating cooling cloud cover
  4. the natural oscillations of Earth’s ocean currents, such as El Nino, La Nina, and others.[71]

The Earth is an immense meet-up of inter-locking, diverse, and dynamic causal factors promoting climate change; related, the planet itself is, relatively, but one dust point in a vastly more immense solar system and galaxy, which unleash yet more diverse natural forces contributing to terrestrial climate change.

Carbon dioxide, whether from natural or man-made sources, is merely one agent in this vast network of causal forces–and, existing in but minute doses in our atmosphere, necessarily a secondary one.




One: Natural-caused, cyclical, and perhaps incessant climate change has occurred for hundreds of millions of years, perhaps longer. The temperature swings caused thereby were, at times, vastly more extensive than the mild warming of our era. For at minimum the past several hundred thousand years atmospheric CO2 buildup lags behind temperature increase. The logical conclusion? Natural forces, not man-made ones, are the overwhelming factor driving modern climate change.

Two: The small warming that we do have is something to be welcomed and celebrated—not something to be feared or curtailed. It is the colder, not the warmer periods of our planet’s history that have been baneful to life. Extensive glaciation killed plant life and drove animals to warmer climes. It was during the warmer interglacial periods that life rebounded. The “Cambrian Explosion” of emerging life forms occurred during a warm, humid period of Earth’s history, not during one of its colder ones.  Human beings flourished throughout the Medieval Warm Period and suffered during the ensuing Little Ice Age.  The Modern Warm Period, like its medieval predecessor, is therefore a boon to be savored prior to the Earth’s next extended cold snap. Dr. Singer states:  “History, science, and our own instincts tell us that cold is more frightening than warmth. . . . The climate event that deserves real concern is the next Big Ice Age. . . . though it may still be thousands of years away.”[72]

Three: By what means can human beings adapt to pernicious, even lethal climate changes?  To protect human life from ice ages, massive volcanism, bolide impact, or whatever other scourges nature has in its arsenal, we must immensely increase our knowledge. How do we do that?

Here, history, economics, and rational philosophy combine to teach us an invaluable lesson.  Human beings must uphold two principles: 1. We must support a culture of reason, a commitment to observation-based rationality as our means of gaining knowledge—and not subordinate reason to feelings or faith 2. We must adopt a politics of individual rights and of capitalism, and put a definitive halt to Western Civilization’s regress into socialism.

When we do this, we can make advances in every field of cognition, as in late-19th and turn-of-the-20th centuries America, when such geniuses as Thomas Edison, Alexander Graham Bell, the Wright brothers, George Washington Carver, William James, Mark Twain (and many others) were free to advance the fields of electrical engineering, telecommunications, aeronautical engineering, agricultural science, experimental psychology, and literature respectively.

When human beings uphold a reverence for reason and a respect for each individual’s inalienable right to his own life and his own mind—and only then—can we develop the science and technology to adapt to such climate calamities as ice ages or the extended “heat wave” of the Eocene Thermal Maximum. By developing central air providing heat and air conditioning, insulated homes, thermal clothing, sun screen, advances in medicine, nuclear fusion reactors, geothermal energy, modern methods of transportation and hence of evacuation, and other forms of progress as unimaginable to us as were airplanes, computers, and the Internet to our ancestors just two centuries ago, we will learn to adapt to severe climate change, whether caused by human forces or, far more likely, the awesome power of nature.

But to do this, we need reason, individual rights, and capitalism. Nothing less—and nothing else—will enable us to flourish—or even to survive.

Four: The AGW hypothesis is mistaken regarding both points two and three delineated at the outset: Modern warming is neither man-made nor pernicious. Rather, it is natural and beneficial.    Additionally, supporters of the AGW hypothesis generally propose, as a panacea, massive government controls of industry and a steep plunge into statism—policies that would strangle the innovativeness and entrepreneurship necessary to combat the climate dangers regarding which they purportedly warn.

Supporters of the AGW hypothesis drop the extended historic context within which modern warming must be understood, they fail to recognize that warm periods in contrast to cold ones are beneficial to life, they ignore the inconvenient truth that atmospheric CO2 buildups follow rather than precede global warming, they are heedless of leading astrophysicists who study the sun-climate connection, and they are profoundly mistaken regarding their proposed solution to “dangerous” climate change.

For all of these reasons, the AGW hypothesis must be rejected.


Andrew Bernstein holds a Ph.D. in Philosophy from the City University of New York. He lectures all over the world. He is a senior writer for the Ayn Rand Institute. He has written numerous books, including his novel, A Dearth of Eagles, recently published and available from Amazon.



[1]  Doug Macdougall, Frozen Earth: The Once and Future Story of Ice Ages (Berkeley, California: University of California Press, 2006), 8

[2] Macdougall, Frozen Earth, 8.

[3] Macdougall, Frozen Earth, 8.

[4] Macdougall, Frozen Earth, 150–160, 209–211. Gabrielle Walker, Snowball Earth: The Story Of The Great Global Catastrophe That Spawned Life As We Know It (New York: Crown Publishers, 2003), 122–28 and passim. Walker recounts the lively story of the “Snowball” theory, of the struggles of its leading proponent, geologist Paul Hoffman, to refine and promote the theory, and of the scientists who critique it.

[5] Fred Singer and Dennis Avery, Unstoppable Global Warming Every 1500 Years (Lanham, Md.: Rowman & Littlefield, 2007), xiii, <http://>, retrieved December 31, 2016.

[6] Macdougall, Frozen Earth, 146–150.

[7] Singer, Unstoppable Gobal Warming Every 1500 Years, xiii.

[8] Singer, Unstoppable Global Warming Every 1500 Years, xiii.

[9]  “Paleocene/Eocene Thermal Maximum,” <http://>, retrieved on May 21, 2017.

[10] “Paleocene-Eocene Thermal Maximum,” <>, retrieved on January 1, 2017.

[11] Tony Hallam, Catastrophes and Mass Calamities: The Causes of Mass Extinctions, (New York: Oxford University Press, 2005), 1–2.

[12] Hallam, Catastrophes and Mass Extinctions, 39–49, quotation on 44.

[13] Singer, Unstoppable Global Warming Every 1500 Years, 77.

[14] Gillen D’Arcy Wood, Tambora: The Eruption That Changed The World (Princeton, NJ: Princeton University Press, 2014), 2.

[15] Wood, Tambora, 3–5.

[16] <>, retrieved on January 2, 2017.

[17] Douglas Erwin, Extinction: How Life On Earth Nearly Ended 250 Million Years Ago (Princeton, NJ: Princeton University Press, 2006), 26.

[18] Erwin, Extinction, 190–194. Basaltic eruptions generally ooze rather than explode, so few of the released gases ever reach the stratosphere; but 10–20 percent of the volcanic material from the Siberian basalt eruptions came from powerful explosions. (Erwin, Extinction, 194.)

[19] Hallam, Catastrophes and Lesser Calamities, 108-29.

[20] Macdougall, Frozen Earth, 1–14. Regarding the ice’s return, the geologist amends his prediction with the qualification “if human activities don’t warm the Earth too severely.” Frozen Earth, 8. But whether human activities play much of a role in warming the Earth is the point in question. We will examine the evidence and we shall see.

[21] Macdougall, Frozen Earth, 7.

[22] Singer, Unstoppable Global Warming Every 1500 Years, xiii–xiv. <>, retrieved on December 30, 2016.

[23] Macdougall, Frozen Earth, 8.

[24] Singer, Unstoppable Global Warming Every 1500 Years, xiv.

[25] Macdougall, 7–8.

[26] Macdougall, Frozen Earth, 215-16. Brian Fagan, The Little Ice Age: How Climate Made History, 1300–1850 (New York: Basic Books, 2000), xv–xvi.  Macdougall, a geologist, provides a graph  (217) indicating temperatures then might have been slightly higher than those of today; Fagan, an archaeologist, says perhaps slightly lower (xvi). However, Fagan also says that on Iceland, “both winter and summer temperatures were usually higher than today” (9); that across the European continent, summer temperatures averaged between 0.7 and 1 degree Celsius (roughly 1.2 to 1.8 degrees Fahrenheit) “above twentieth century averages” (17); and that “Central European summers were even warmer, as much as 1.4 degrees C [approximately 2.5 degrees Fahrenheit] higher than their modern averages” (17).

[27] Macdougall, Frozen Earth, 215–16. Fagan, The Little Ice Age, 3–21.

[28] Singer, Unstoppable Global Warming Every 1500 Years, 102-04.

[29] Doug Macdougall, Frozen Earth, 221.

[30] Arthur Herman, How The Scots Invented the Modern World (New York: Crown Publishers, 2001), 9.

[31] Fernand Braudel, The Structures of Everyday Life: The Limits of the Possible (New York: Harper & Row, 1981), 77.  

[32] These are merely two of the naturally-cycling climate eras of relatively recent history. Preceding the Medieval Warm Period was the Dark Age Cold Period (roughly 8th and 9th centuries AD), during which Northern Hemisphere temperatures were generally lower than in the warmer era that followed. Prior to that was the Roman Warm Period (approximately 200 BC to 500 AD). Before that occurred an unnamed cold period preceding the Roman Warming (roughly 700 to 200 BC). Singer, Unstoppable Global Warming Every 1500 Years, 99–102.

[33] John Houghton, Global Warming: The Complete Briefing, Fourth Edition (Cambridge, England: Cambridge University Press, 2009), 75, 76–77.

[34] Singer, Unstoppable Global Warming Every 1500 Years, xv. Lawrence Solomon, The Deniers: The World-Renowned Scientists Who Stood Up Against Global Warming Hysteria, Political Persecution, and Fraud (Minneapolis, Minn.: Richard Vigilante Books, 2008), 76–78, 140, 167–171.

[35] Peter Gwynne, “The Cooling World,” Newsweek, April 28, 1975, republished on Denis Dutton’s website, <>, retrieved on January 2, 2017.

[36] Quoted in Solomon, The Deniers, 74.

[37] Solomon, The Deniers, 9-21.

[38] Solomon, The Deniers, 13-15. The most disturbing features of this case are not that Mann was profoundly mistaken; we are human beings, after all, we make errors. It was that he was extremely reluctant to share his data, his methods, and his algorithm, making it difficult to independently verify or refute his findings; it is that today, in the face of enormous contrary evidence, he and his supporters continue to uphold the hockey stick graph, and that he verbally assails his critics. Mann and his supporters do not merely deny historical periods of natural climate change; they do so dogmatically.

[39] Quoted in Solomon, The Deniers, 75. See also Houghton, Global Warming: The Complete Briefing, 20–27.

[40] CO2.Earth:  Are We Stabilizing Yet?, 2007–2017, <>, retrieved on January 5, 2017. Breitbart London,  “Greenpeace Founder: Let’s Celebrate CO2,” October 15, 2015, <>, retrieved on December 14, 2016.

[41] Singer, Unstoppable Global Warming Every 1500 Years, 36–37, quote on 37.

[42] Quoted in Solomon, The Deniers, 95.

[43] Quoted in Solomon, The Deniers, 93.

[44] Singer, Unstoppable Global Warming Every 1500 Years, 11.

[45] Singer, Unstoppable Global Warming Every 1500 Years, 10.

[46] Singer, Unstoppable Global Warming Every 1500 Years, 10.

[47] Richard Lindzen, “Thoughts on the Public Discourse over Climate Change,”, retrieved on June 4, 2017. See also: Paul Homewood, “RSS Confirm 2016 Is Tied With 1998 As Warmest Year,” Not a Lot of People Know That, January 5, 2017, <>, retrieved January 8, 2017.  See further: Christopher Monckton, “Global Temperature Standstill Lengthens: No Global Warming For 17 Years 10 Months—Since September 1996 (214 Months),” <>, retrieved on January 6, 2017. See finally: Roy W. Spencer, “UAH V6 Global Temperature Update for April, 2016 +0.71 Deg. C,” Roy Spencer, Ph.D., May 2, 2016, <>, retrieved on January 8, 2017.

[48] Solomon, The Deniers, 142.

[49] Solomon, The Deniers, 93. Singer, Unstoppable Global Warming Every 1500 Years, 241.

[50] Kate Ravilious, “Mars Melt Hints at Solar, Not Human, Cause for Warming,  Scientist Says,” National Geographic News, February 28, 2007, <>,  retrieved on April 14, 2017.

[51] Quoted in Solomon, The Deniers, 161. Abdussamatov believes  there may be evidence for warming in other parts of the solar system, as well, although he does not specify what it is. See Marc Morano, “New Paper Predicts Another Little Ice Age Within the Next 30 Years,” The Hockey Schtick, December 4, 2013, <>, retrieved May 21, 2017.

[52] Quoted in Solomon, The Deniers, 162.

[53] Singer, Unstoppable Global Warming Every 1500 Years, 192.

[54] Singer, Unstoppable Global Warming Every 1500 Years, 192.

[55] Solomon, The Deniers, 84.

[56] Quoted in Solomon, The Deniers, 163.

[57] Henrik Svensmark and Nigel Calder,  The Chilling Stars: A New Theory of Climate Change (Cambridge, England: Icon Books, 2007), 5–7 and passim. Singer, Unstoppable Global Warming Every 1500 Years, 9. Solomon, The Deniers, 143–160.

[58] Solomon, The Deniers, 155–156.

[59] Svensmark, The Chilling Stars, 7.

[60] Eugene Parker, “Foreword” to Svensmark, The Chilling Stars, vii-viii.

[61] Singer, Unstoppable Global Warming Every 1500 Years, 193-94. Solomon, The Deniers, 143.

[62] Macdougall, Frozen Earth, 75–80.

[63] Macdougall, Frozen Earth, 129–140.

[64] Macdougall, Frozen Earth, 124–125. Singer, Unstoppable Global Warming Every 1500 Years, 23.

[65] Macdougall, Frozen Earth, 83–84.

[66] Singer, Unstoppable Global Warming Every 1500 Years, 5, 10, 24, 191–92, and passim.

[67] Singer, Unstoppable Global Warming Every 1500 Years, 192. S. Baliunas and W. Soon, “Solar Variability and Climate Change,” Astrophysical Journal 450 (1995): 896, cited in Singer, 192.

[68] Solomon, The Deniers, 163.

[69]Elizabeth Howell, “How Long Have Humans Been on Earth?”, Universe Today, December 23, 2015, <>, retrieved on December 30, 2016.

[70] Michon Scott and Rebecca Lindsay, “What’s the hottest Earth’s ever been?” Retrieved on June 2, 2017.

[71] “El Nino and Other Oscillations,”, retrieved on June 4, 2017.

[72] Singer, Unstoppable Global Warming Every 1500 Years, 15, 17.

Eight Years Later…

From UN scientists warn time is running out to tackle global warming | Environment | The Guardian: (Published in May 2007)

Governments are running out of time to address climate change and to avoid the worst effects of rising temperatures, an influential UN panel warned yesterday.

Greater energy efficiency, renewable electricity sources and new technology to dump carbon dioxide underground can all help to reduce greenhouse gas emissions, the experts said. But there could be as little as eight years left to avoid a dangerous global average rise of 2C or more.

The warning came in a report from the Intergovernmental Panel on Climate Change (IPCC) published yesterday in Bangkok. It says most of the technology needed to stop climate change in its tracks already exists, but that governments must act quickly to force through changes across all sectors of society. Delays will make the problem more difficult, and more expensive.

Rajendra Pachauri, who chairs the IPCC, said the report would underpin negotiations to develop a new international treaty to regulate emissions to replace the Kyoto protocol when it expires in 2012.

The report said little on the best way to encourage greater take-up of cleaner technologies. A delegate present at the negotiations said the passages on international policy options had been watered down by the US, which is opposed to Kyoto-style agreements that rely on binding targets.

Harlan Watson, head of the US delegation, said the report “highlights the importance of a portfolio of clean energy technologies, consistent with our approach”.

There were also rows about the role of nuclear power, with countries including Spain and Austria opposed to any form of words that endorsed an increase in electricity from nuclear technology.


Yesterday’s report follows two studies by the IPCC this year, which said unrestrained greenhouse gas emissions could drive global temperatures up as much as 6C by 2100, triggering a surge in ocean levels, destruction of vast numbers of species, economic devastation in tropical zones and mass human migrations.

The report said global emissions must peak by 2015 for the world to have any chance of limiting the expected temperature rise to 2C, which would still leave billions of people short of water by 2050.

Quoting energy expert Alex Epstein “8 years ago, they said we had only 8 years to avoid a climate catastrophe. Climate danger is now at an all-time low.”

Climate Has Been Changing Since The Earth Was Formed

From Richard S. Lindzen: The Political Assault on Climate Skeptics – WSJ:

Research in recent years has encouraged those of us who question the popular alarm over allegedly man-made global warming. Actually, the move from “global warming” to “climate change” indicated the silliness of this issue. The climate has been changing since the Earth was formed. This normal course is now taken to be evidence of doom.

Individuals and organizations highly vested in disaster scenarios have relentlessly attacked scientists and others who do not share their beliefs. The attacks have taken a threatening turn.

As to the science itself, it’s worth noting that all predictions of warming since the onset of the last warming episode of 1978-98—which is the only period that the United Nations Intergovernmental Panel on Climate Change (IPCC) attempts to attribute to carbon-dioxide emissions—have greatly exceeded what has been observed. These observations support a much reduced and essentially harmless climate response to increased atmospheric carbon dioxide.

In addition, there is experimental support for the increased importance of variations in solar radiation on climate and a renewed awareness of the importance of natural unforced climate variability that is largely absent in current climate models. There also is observational evidence from several independent studies that the so-called “water vapor feedback,” essential to amplifying the relatively weak impact of carbon dioxide alone on Earth temperatures, is canceled by cloud processes.

There are also claims that extreme weather—hurricanes, tornadoes, droughts, floods, you name it—may be due to global warming. The data show no increase in the number or intensity of such events. The IPCC itself acknowledges [1]the lack of any evident relation between extreme weather and climate, though allowing that with sufficient effort some relation might be uncovered.

World leaders proclaim that climate change is our greatest problem, demonizing carbon dioxide. Yet atmospheric levels of carbon dioxide have been vastly higher through most of Earth’s history. Climates both warmer and colder than the present have coexisted with these higher levels.

Currently elevated levels of carbon dioxide have contributed to increases in agricultural productivity. Indeed, climatologists before the recent global warming hysteria referred to warm periods as “climate optima.” Yet world leaders are embarking on costly policies that have no capacity to replace fossil fuels but enrich crony capitalists at public expense, increasing costs for all, and restricting access to energy to the world’s poorest populations that still lack access to electricity’s immense benefits.

The 97% Consensus on a Dangerous Global Warming Catastophe is Really 1%

From Joseph Bast and Roy Spencer: The Myth of the Climate Change ‘97%’ – WSJ:

Last week Secretary of State John Kerry warned graduating students at Boston College of the “crippling consequences” of climate change. “Ninety-seven percent of the world’s scientists,” he added, “tell us this is urgent.”

Where did Mr. Kerry get the 97% figure? Perhaps from his boss, President Obama, who tweeted on May 16 that “Ninety-seven percent of scientists agree: #climate change is real, man-made and dangerous.” Or maybe from NASA, which posted (in more measured language) on its website, “Ninety-seven percent of climate scientists agree that climate-warming trends over the past century are very likely due to human activities.”

Yet the assertion that 97% of scientists believe that climate change is a man-made, urgent problem is a fiction. The so-called consensus comes from a handful of surveys and abstract-counting exercises that have been contradicted by more reliable research.

One frequently cited source for the consensus is a 2004 opinion essay published in Science magazine by Naomi Oreskes, a science historian now at Harvard. She claimed to have examined abstracts of 928 articles published in scientific journals between 1993 and 2003, and found that 75% supported the view that human activities are responsible for most of the observed warming over the previous 50 years while none directly dissented.

Ms. Oreskes’s definition of consensus covered “man-made” but left out “dangerous”—and scores of articles by prominent scientists such as Richard Lindzen, John Christy, Sherwood Idso and Patrick Michaels, who question the consensus, were excluded. The methodology is also flawed. A study published earlier this year in Nature noted that abstracts of academic papers often contain claims that aren’t substantiated in the papers.


In 2013, John Cook, an Australia-based blogger, and some of his friends reviewed abstracts of peer-reviewed papers published from 1991 to 2011. Mr. Cook reported [7]that 97% of those who stated a position explicitly or implicitly suggest that human activity is responsible for some warming. His findings were published in Environmental Research Letters.

Mr. Cook’s work was quickly debunked. In Science and Education in August 2013, for example, David R. Legates (a professor of geography at the University of Delaware and former director of its Center for Climatic Research) and three coauthors reviewed the same papers as did Mr. Cook and found “only 41 papers—0.3 percent of all 11,944 abstracts or 1.0 percent of the 4,014 expressing an opinion, and not 97.1 percent—had been found to endorse” the claim that human activity is causing most of the current warming. Elsewhere, climate scientists including Craig Idso, Nicola Scafetta, Nir J. Shaviv and Nils- Axel Morner, whose research questions the alleged consensus, protested that Mr. Cook ignored or misrepresented their work.


There is no basis for the claim that 97% of scientists believe that man-made climate change is a dangerous problem.

The Myth of the Climate Change ‘97%’

Write Joseph Bast and Roy Spencer in

[T]he assertion that 97% of scientists believe that climate change is a man-made, urgent problem is a fiction. The so-called consensus comes from a handful of surveys and abstract-counting exercises that have been contradicted by more reliable research.

[…] Another widely cited source for the consensus view is a 2009 article in “Eos, Transactions American Geophysical Union” by Maggie Kendall Zimmerman, a student at the University of Illinois, and her master’s thesis adviser Peter Doran.

It reported the results of a two-question online survey of selected scientists. Mr. Doran and Ms. Zimmerman claimed “97 percent of climate scientists agree” that global temperatures have risen and that humans are a significant contributing factor.

The survey’s questions don’t reveal much of interest. Most scientists who are skeptical of catastrophic global warming nevertheless would answer “yes” to both questions. The survey was silent on whether the human impact is large enough to constitute a problem. Nor did it include solar scientists, space scientists, cosmologists, physicists, meteorologists or astronomers, who are the scientists most likely to be aware of natural causes of climate change.

[…] In 2013, John Cook, an Australia-based blogger, and some of his friends reviewed abstracts of peer-reviewed papers published from 1991 to 2011. Mr. Cook reported that 97% of those who stated a position explicitly or implicitly suggest that human activity is responsible for some warming. His findings were published in Environmental Research Letters.

Mr. Cook’s work was quickly debunked. In Science and Education in August 2013, for example, David R. Legates (a professor of geography at the University of Delaware and former director of its Center for Climatic Research) and three coauthors reviewed the same papers as did Mr. Cook and found “only 41 papers—0.3 percent of all 11,944 abstracts or 1.0 percent of the 4,014 expressing an opinion, and not 97.1 percent—had been found to endorse” the claim that human activity is causing most of the current warming. Elsewhere, climate scientists including Craig Idso, Nicola Scafetta, Nir J. Shaviv and Nils-Axel Morner, whose research questions the alleged consensus, protested that Mr. Cook ignored or misrepresented their work.

[…] Surveys of meteorologists repeatedly find a majority oppose the alleged consensus. Only 39.5% of 1,854 American Meteorological Society members who responded to a survey in 2012 said man-made global warming is dangerous.

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