List of errors and half-truths (half-truths indentified by "HT") (note that correct figures, such as population data, are as of 1997):
"Asteroid belt" is a somewhat confusing term. The main belt is between Mars and Jupiter, but 427 known asteroids pass within the orbit of Mars, 405 orbit in Jupiter's L4 and L5 positions (in Jupiter's orbit), and 57 have an average distance beyond the orbit of Jupiter.
This statement perpetuates student misconceptions about the ozone layer. Ozone is a gas found at all altitudes, but with concentrations peaking in the upper and lower stratosphere. Even in the ozone "layer" ozone makes up a small fraction of total gas (3 parts per million).
The Gaia hypothesis, as stated, may be a meaningful analogy but it is poor science. Lovelock himself describes his "hypothesis" as "postulat[ing] that the physical and chemical condition of the surface of the Earth, of the atmosphere, and of the oceans has been and is actively made fit and comfortable by the presence of life itself." This statement is very different from saying that the Earth is a single organism. Even Lovelock's actual statement is almost universally regarded as unscientific in the mainstream scientific community, although substatements pertaining to environmental feedback mechanisms can be evaluated scientifically. Such feedback mechanisms have been examined by other scientists and are illustrated by Lovelock's simplistic "Daisyworld" model. However, describing the Earth as an organism is given credibility not by scientists but by New Age religious adherents. Therefore, unqualified discussion of the Gaia hypothesis does not belong in a science textbook.
This statement is misleading; Lovelock was part of a large team of scientists who examined ambiguities in the data for months before concluding that Mars was lifeless. Giving Lovelock sole credit is a denial of the way the scientific community actually works.
Data in the graph is incorrect. Per capita grain consumption has increased in Africa.
Tabled data on deforestation is exaggerated. According to data from the UN FAO, area of tropical forest in Brazil in 1990 was 396,000 thousand hectares with a deforestation rate of less than 0.9% per year; deforestation in India is about 0.8% per year and in Ivory Coast about 4.9% per year.
The current scientific consensus is that the early terrestrial atmosphere included significant fractions of nitrogen and water vapor as well as CO2. Carbon dioxide probably never made up a majority of the Earth's atmosphere.
Emperical evidence indicates that population will level off due to socio-economic transformations long before terrestrial resources are depleted. The authors' statement ignores any utilization of as-yet unrecognized resources, which has historical been the normal response to price increases of a specific resource. It also ignores any future contribution of extra-terrestrial resources.
Estimated number of total species is from 8 to 10 million. The World Wildlife Fund claims that widely accepted estimates range from 4.4 to 33.5 million, with some sources going as high as 50 million.
This statement contradicts itself; if studies showed 5,000 species in 1 gram of soil, then 5,000 species would have to be identified.
Only about 1,000 animal and vascular plant species are documented as having become extinct, and about 75% of these species were in isolated island habitats. Even given accepted estimates of undiscovered species, the figures stated in the text are two or three orders of magnitude greater than what can be scientifically defended.
The given parameters lead the student to a false conclusion concerning world population growth and food needs, since the modeled behavior is not remotely linear. World population growth is currently decreasing and the agricultural productivity per unit area of arable land is increasing. Moreover, outside of the Western nations agricultural productivity remains far below attainable levels. Current annual increase in the world's population is 1.6 percent.
At no point in the last 75 years has the U.S. timber industry been consuming trees at an unsustainable rate. Since 1920, both total forested area and total standing timber biomass in the U.S. have been increasing. In the past 40 years, standing timber biomass in the U.S. has increased over 20 percent.
Increased automation is not an issue in the timeframe or location of the spotted owl debate. Increased exports would increase jobs, not cause job losses. The rate of log harvesting in question was in fact sustainable because it remains below the rate of increase in timber biomass. The conflict in Oregon arose not because the timber industry sought permission to clear-cut forests but because environmentalists did not want any logging at all to occur.
Yellowstone was affected by 13 fires over a three-month period, some of which merged.
Tropical rain forests currently cover 13 percent of the Earth's land area, compared with perhaps 17 percent prior to human activity.
This sentence incorrectly implies that there are many individual species unique to a single tree. The figure of 43 ant species seems arbitrary; it is not clear if this is an average or an upper limit or if it represents known or hypothetical species.
The incorrect data from p. 148 is repeated, and the suggestion that rain forests might disappear by 2015 has no factual basis. If current rates of deforestation are unchanged, it would take at least 107 years to wipe out the tropical forests.
Mandated efforts to provide water to Everglades National Park began in 1970; the Southwest Dade Project, the resulting project to provide water to the park, involved several canals and was not completed until 1978.
Native Americans had neither a single world view nor a spherical Earth model. Native Americans generally considered the Earth to be flat, and they included many different cultures with views widely differing in the details shown. The parallels portrayed between constituent tissue of a personified "earth god" and the structure of the Earth are completely arbitrary and cannot be derived from Native American views. No "similarity" exists between animal structure and Earth structure. The linkage of pagan religion to geology is not scientific and does not belong in a science textbook--particularly a science textbook in a state-sponsored school.
The Earth is 99.99999% inorganic matter and is not an organism; this statement is not science and cannot be a hypothesis. This statement repeats the errors of page 14.
This paragraph implies that the scientific community is coming to accept Lovelock's "hypothesis" as science, which is false. Some scientifically testable hypotheses have been refined from his original contention, but mainstream scientists still consider the Gaia hypothesis unscientific. It is among fringe groups that acceptance has increased.
Inset locator map gives incorrect location of French Guiana.
This model completely misrepresents real-world behavior. In reality, the period of time required to exhaust currently known reserves at current rates of consumption of zinc (and nearly all other non-renewable resources) has consistently increased during this century. Note specifically: (3a) Economically recoverable resources of zinc or any other mineral are increasing because improved technology is making lower grade deposits economic to mine and because new reserves are being discovered. Using this model's scale, economically recoverable resources were 35 paper clips in 1950, 56 paper clips in 1970, 72 paper clips in 1990, and 165 paper clips in 1996. (3b) Natural processes do not create zinc ore in remotely significant amounts over the time frame illustrated; moreover, natural creation of zinc is canceled out by the erosion of zinc ore. Even worse, as outlined, the model suggests that natural processes will create ore for the next 40 years and then stop doing so. This step should be omitted. (5) World production and consumption of zinc are not increasing exponentially, and certainly not at an annual rate of increase of 14% as portrayed. Rate of increase of zinc production is much smaller and is too inconsistent to model exponentially. In fact, U.S. production of zinc has fluctuated up and down considerably in the last 40 years. Using this model's scale, world production of zinc is 15 paper clips per minute of simulation. Analysis question 2 and the questions of the conclusion cannot be addressed at all on the basis of the simulation. If anything here can be modeled by exponential increase, it is proven reserves and not world consumption. The Malthusian prediction of resource exhaustion which students are led to on the basis of this activity has been disproven.
Deaths from World War II numbered between 30 and 60 million.
Scientists do not make this claim because overpopulation is not scientifically defined. The problems attributed here to overpopulation are a result of poverty, not of population density. There is no scientific basis for the assertion that population growth could result in human extinction.
In 1989 Egypt birth rate was 35 per 1,000 people and death rate was 10 per 1,000 people. The correct natural growth rate is 2.5%.
Current population doubling times for the listed nations are 39, 30, 21, 26, and 26 years, respectively. Peru and Kenya should be omitted from this statement.
Health problems are not directly tied to overpopulation (because overpopulation cannot be rigorously defined) but to poverty.
The statement and discussion inappropriately imply that these cultural beliefs should be changed. Changing family size is not scientifically warranted. The preceding statements can be construed as ethnocentric by some cultures. More specifically, the discussion implies that certain Hispanic cultural values are at odds with education and/or science.
This vastly understates the pressure of the PRC's population policy. In many cases, those who have an unapproved pregnancy are forced against their will to submit to abortions with physical force. More frequently they have their jobs or living quarters taken away. In all cases, the government denies benefits to the second child--which is a severe problem for the innocent child where the state controls all benefits. This also ignores the infanticide, mostly of female infants, which has mushroomed because of the PRC's policies.
This ignores the fact that the assessed limits vary by orders of magnitude. Most scientists feel we will not attain such a limit in the foreseeable future.
The activity is inappropriate for public school students, since it asks them to individually model transmission of a sexually transmitted disease (re: "partner", "exchanged fluids").
The Green revolution has increased food supplies in underdeveloped countries. The reasons listed for lack of access are far less important than policies of centralized governments in the Third World.
Figure is exaggerated, may have meant one-quarter of agriculturally useful land.
The statement links agricultural subsidies to the Reagan administration when in fact such policies were previously well established.
The U.S. federal government budgeted $11.25 billion for food stamps in fiscal year 1981, $11.01 billion in fiscal year in FY 1982, and $11.84 in fiscal year 1983. The cut from FY 1981 to FY 1982 was 0.24 billion dollars, not "billions of dollars". (The same applies to other programs: the cut from FY 1981 to FY 1982 for the Child Nutrition Program was $0.42 billion.)
The poverty level is the federally defined level of income below which persons are considered to be in poverty; this is always increasing because it is adjusted for inflation. The poverty rate (what the authors are trying to say) was 15.0% in 1982 and was 17.3% in 1965, only 17 years previously. Twenty years previously the poverty rate was 20.1%. Once Reagan's economic policies went into effect, the poverty rate dropped to 12.8%.
This is not the whole truth. Nuclear energy production, despite overregulation, remains cheaper than fossil fuel energy production; questions of safety and waste disposal have been adequately addressed.
This total incorrectly combines the isotopic averages of naturally occurring barium and krypton and does not represent atoms which could result from a uranium fission.
While U-238 does not chain react, it does contribute to nuclear reactions and is thereby the source of plutonium.
The statement uses incorrect terminology. U-238 is fissionable (can be induced to fission); U-235 is fissile (can chain react).
U-235 splits from fast or slow neutrons, otherwise an atomic bomb wouldn't work.
Mass of the fission products without neutrons is 0.988 kg on average and with neutrons is 0.9992 kg on average. To "Ignore the mass released as free neutrons" is procedurally incorrect, since this mass is not negligible; the result is an answer too large by a factor of 70.
Correct breakdown of this three percent is: 3% consumer products (primarily televisions), 0.3% workplace, 0.2% nuclear tests, 0.1% nuclear fuel cycle, 0.01% nuclear power plants. The result misrepresents contribution of nuclear testing and power by a factor of 30.
The discussion is incorrect to directly link hazards of radioisotopes to half-life. Longer half-life means lower levels of radioactivity. The discussion implies that natural uranium with longer half-life is more dangerous than high-level wastes, and implies that stable oxygen, with infinite half-life, is dangerous forever. In reality, high-level waste disposed in glass is less radioactive than natural uranium in 400 years and transuranic waste (including plutonium) disposed in glass in 2,000 years.
Plutonium only poses a deadly threat if deposited in the lungs as microscopic particles. Solid plutonium can be safely touched and has even been ingested with no short-term effects.
The statement is totally meaningless without defining "safe level". This uses same flawed understanding from page 257.
The only accidental radiation releases from the TMI accident were of krypton, lesser amounts of other noble gases, and a relatively small amount of iodine. "Radioactive steam and water" was released in an intentional, controlled manner and was water containing dissolved noble gases, particularly krypton and xenon.
The discussion incorrectly confuses RBMK reactors like Chernobyl and LWR reactors like U.S. commercial reactors (including TMI). Chernobyl did not have a containment vessel. RBMK reactors have a totally different design from LWR reactors, creating failure modes which are completely impossible in an LWR. These potential failure modes (such as the one at Chernobyl) are more a reflection of physics of construction rather than specific safety features. The different between Soviet RBMK reactors and U.S. LWR reactors is not between old and new but in design--U.S. LWR reactors are designed to be inherently safe. The Chernobyl reactor was less than three years complete at the time of the accident, having begun operation in 1983; the U.S. has operated LWR reactors since 1957.
Graphite is a moderator, not a neutron absorber and thence not a material for control rods. The control rods were made of boron carbide and other compounds.
Only 2 people were killed immediately. A third person died the next day, and a total of 31 people have died to date, all within a few months of the accident.
Human error is eliminated by designing plants incapable of an accident such as Chernobyl experienced. This is the case for U.S. commercial reactors. TMI did not result in harm beyond property damage to the operating company because built-in safeguards mitigated the effect of repeated human operator error.
A breeder reactor uses U-238, U-235, and Pu-239 (b, c, and d).
All matter in the environment contains radioisotopes and therefore gives off radiation. (Using this criterion the human body, containing K-40, is always dangerous.) The intensity of emitted radiation is directly dependent on (1) the derivative of the radioactive decay curve with respect to time and (2) the quantity of radioisotope present. Because of the former, isotopes with shorter half-lives are initially far more radioactive but reach levels comparable to background rates much sooner. High-level radioactive wastes from reactor cores are so dangerous not because of plutonium they contain but because of large quantities of fission fragments which include isotopes with half-lives ranging from days to a few decades.
The statement in question 2 is incorrect and answer in TE to this question on p. T89 is also incorrect. Fission bombs do not use isotopically pure fissile material, U-235 or otherwise; the Mk-I Little Boy used in 1945 used 80% U-235, 20% U-238. The assembled critical mass is induced by a separate neutron source to begin chain reacting; if it were allowed to spontaneously begin a chain reaction as the question states then negligible nuclear yield would result. The TE's answer is completely incorrect: the energy release in the Chernobyl accident was from a steam explosion and a chemical explosion involving liberated hydrogen. The Chernobyl reactor, even without control rods, is incapable of exploding like a fission bomb because the fissile isotopes present are diluted with much larger quantities of U-238, fission products, graphite, water pipes, and other structural material. The meltdown did not necessarily slow down the reaction; the melted reactor core continued to generate sufficient heat to burn graphite for about a week.
Earth receives 2 billionths of the energy produced by the Sun, not 0.5 billionths as the statement indicates.
Any form of converting solar energy to electrical or mechanical energy involves industrial production of energy collection devices and continuous energy storage; both processes involve chemical wastes.
These wind farms produce an average of about 250 MWe. The statement implies a large nuclear reactor produces 500 MWe; the correct figure is 1,100 MWe. Thus, together, these five wind farms produce about one-fourth of the electricity of a large nuclear reactor.
This statement perpetuates a common misconception about risk assessment and should be avoided in the context of science education. Risk assessment involves examining dispersion, not just toxicity and quantity. (The lake also contains enough water to drown every person in Europe.)
This statement is questionable. If it were true, then those 1250 sq. km are covered by an average thickness of 2.0 cm of toxic waste. If the 4.5 x 108 metric ton figure is correct, then the mode and density of dispersion is highly variable. Moreover, "radioactive waste" here refers to uranium tailings, which are less radioactive than natural uranium, and constitutes a small fraction of the relevant material.
This statement should be qualified in that the radon contribution is highly variable. Along the Texas coast, for example, the contribution from radon is less than 1 percent.
First, only 0.0000002% of the UV radiation given off by the Sun is intercepted by the Earth at all. Second, ozone absorbs only UV-B, which is a fraction of the UV spectrum. Failure to make this distinction develops a misconception associated with cancer risk.
Use of the term "hole" (nine times in this section) perpetuates a common student misconception about the ozone situation. At issue is a depletion in ozone concentrations which is both regional and seasonal, lasting for only a few weeks each year; depletions range from 20 to 50%, not the total absence implied by the term "hole". While "ozone hole" is the term in popular usage and therefore must be used in the discussion, it is essential to accurately characterize the phenomena not as a hole but as a transient depletion. To do otherwise (as this section does) develops a significant misunderstanding with many students.
The debate is not quieter due to a scientific consensus on the topic (because there is none); the debate is quieter because political activists have largely succeeded in their goals of outlawing the pertinent chemicals and have turned their campaigning to other issues. If anything, mainstream scientists have somewhat downgraded the severity of predictions of ozone depletion.
This ozone loss progresses during the Antarctic winter with depletion peaking in the spring. The statement that half is lost each spring ignores the fact that the ozone is restored each summer.
This cited depletion is a result of selective data interpretation: for the time period in question (1978-1990), total ozone decreased by 2 percent over 8 years, then increased by 1 percent in the next 4 years.
Ozone only absorbs UV-B radiation, not UV-A. Medical studies indicate that malignant melanoma, the type of skin cancer with a significant mortality rate, is caused by UV-A radiation which is not affected by ozone levels.
Observationally, photoplankton populations in the Antarctic have not been affected by the presence of the ozone "hole". This indicates either that photoplankton is not as sensitive to UV as feared, or that UV levels in the Antarctic have not increased.
This statement is hardly a confirmed fact and flies in the face of quite a bit of scientific evidence. The causal link between surface CFC emissions and stratospheric ozone depletion is not experimentally demonstrated. Ozone depletion has been correlated with chlorine abundance, but the source of chlorine is not definitively linked to CFCs. Additionally, ozone depletion does not correlate observationally with cumulative CFC emissions. Ozone depletion does, however, correlate strongly with solar activity, both observationally and theoretically, suggesting that variable high energy solar radiation is the main cause of ozone depletion.
The chlorine atom is present throughout the reaction, so it cannot be regenerated; "liberated" would be a better word.
The most abundant CFCs have atmospheric lifetimes of 50-100 years. Some have lifetimes as low as 5 years; some types produced in very small quantities have longer lifetimes. Additionally, CFCs do not affect ozone until they are broken down into constituent atoms.
These experiments have not established what is claimed, given the limited geographical domain involved. Volcanoes far from the Alps do periodically inject chlorine directly into the stratosphere.
Many scientists have downgraded the earlier, more severe predictions of ozone depletion.
This discussion teaches an incorrect understanding of the process which will have to be untaught when the student comes to thermodynamics. Electromagnetic energy (visible and otherwise) from the Sun is partially absorbed by the Earth and atmosphere, heating both. Both the Earth and atmosphere radiate infrared EM energy as a result. Some infrared energy is selectively absorbed by greenhouse gases, warming the atmosphere. This results in a higher equilibrium temperature for the Earth. A pane of glass traps warm air and prevents convection while greenhouse gases alter the radiative balance. The atmospheric phenomena referred to as the greenhouse effect is fundamentally different from what heats a greenhouse.
"Greenhouse gas pollution" is a misnomer because the primary anthropogenic emission of concern is carbon dioxide, which is indistinguishable from the natural carbon dioxide essential to survival of life on Earth. The diagram also implies infrared radiation is reflected by greenhouse gases, which is not the case.
Greenhouse gases do not trap heat; they selectively absorb electromagnetic energy.
The most important natural greenhouse gas is water vapor. Water vapor constitutes an average of 0.4% of the atmosphere, compared to 0.037% for carbon dioxide.
It is inaccurate to depict the debate in this manner. Given their policy successes, environmentalists are arguably as powerful as the "fossil fuel industry". Moreover, these are not the only participants in the debate: economists, mainstream scientists (on both sides), politicians (for various reasons on both sides), anti-technologists, socialists, etc.
The primary greenhouse gas emitted is carbon dioxide, which is not a pollutant.
The data represented in this figure is characterized by such uncertainty as to be largely speculative. Current computer models produce no consensus on predicted regional results of presumed global warming. The data depicted is generalized to the point of being nearly useless. In particular, "regions of potentially large population displacement" involve too many other factors to be predicted on the basis of computer temperature modeling, and "areas vulnerable to sea level rise" are depicted in a manner which exaggerates the land area involved by several orders of magnitude.
The United Nations IPCC estimates a temperature increase of 1 C to 3.5 C by the year 2100; the statement in the text inflates predictions by a factor of 2 to 4. Computer models are not consistent in their predictions, and many flaws in the models remain uncorrected, making it inappropriate to treat them as fact.
This final paragraph inappropriately treats global warming as a certainty, which it is not.
The current predictions of the U.N. IPCC (which remain more extreme than those of many mainstream climatologists) are for a sea level rise of 0.15 to 0.95 m by 2100. Were this to occur, few areas would be dramatically impacted beyond Bangladesh and small island nations. A sea level rise of 3 m to 30 m would be required to flood New York and Los Angeles.
Students have been given absolutely no basis with which to evaluate the computer models. The computer models have been misrepresented as faithful models of the atmosphere, and no information at all is provided on the discrepancies among computer models and between computer models and the real atmosphere.
Additional reasons include the lack of conclusive scientific evidence, the fact that immediate action is not necessitated by model predictions, the potential human mortality that would result from proposed limits, and the failure of proponents of such limits to consider workable alternatives.
The computer model outlined has no relation to actual stratospheric chemistry. In reality, ozone is created from stratospheric oxygen by solar ultraviolet, replacing lost ozone.
There is minimal scientific basis for the scenario depicted in this exercise, given the natural processes that over time replace ozone.
The correct figure is 185,000 hectares annually, although this may include areas mislabeled by the current EPA interpretation of "wetlands". This statement also omits reference to the fact that 400,000 hectares of wetlands are being restored annually.
Recycling paper uses more energy than producing paper from trees, when the energy cost of gathering the paper for recycling is included. This is the explanation for the relatively low rate of recycling for paper.
The usefulness of this statistic is limited without an indication of the criterion for contamination; what level of impurity may be far more or far less than 1 ppm depending on the proposed use. Moreover, the authors have converted the EPA figures from gallons to liters apparently without realizing that they merely represent a ratio.
The energy savings of recycling varies from material to material and in many cases does not save energy, paper and plastic being prime examples.
Conversion error: 100,000 hectares is 386 square miles.
The caption incorrectly connects "environmental disaster is almost certain" with "a residential area...next to ... a nuclear power plant." This innuendo is groundless.
Deaths per million hours of exposure to "Living near a nuclear power plant" is not 0.5 but approximately 5 x 10-7 for U.S. nuclear power plants (or 10-5 for Russian RBMK reactors). The statement "The only time to be certain of a risk is after problems occur." is an incorrect understanding of risk analysis.
Glossary: (the following definitions are erroneous)
© 1997, 2002 by Wm. Robert Johnston.
Last modified 24 May 2002.
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