Despite the editors' meticulous avoidance of favoring one view over another, it is impossible not to conclude from the papers selected that the present warming trend is caused predominantly, if not entirely, by natural phenomena.  Anthropogenic effects on temperature cannot be distinguished in the present warming, as the planet recovers from the Little Ice Age with resulting temperature changes within the expected range.  The comparison with past climate changes and the analysis of all known climate change drivers effectively deflate the politically-driven sense of urgency to act in order to avoid a man-made climate calamity.  Indeed, the book's collection of insight seriously questions whether the concept of man-induced climate change reversal is feasible at all.

The politically-driven perception that action is urgently needed to stop global warming arises from the prevalent notion that Earth's climate has been stable and benign for the longest time and is only now suddenly beginning to undergo ominous change as a result of mankind's interference with nature.  This concept is in conflict with the reasoned approach of scientists questioning the need and efficacy of such action.  It is not widely understood that climate is never stable; it changes constantly.  Politicians are upset about the possibility of a very minor sea level change, and are unaware that only 14,000 years ago the sea level was over 500 feet below what we consider 'normal'.

Since political movements aspire to interpret scientific arguments by majority rule, it may be impossible to stop a nonsensical waste of resources in a futile attempt to alter what in all likelihood is nothing more than a natural change in climate.  Scientists are at a loss to explain sophisticated and complex issues to a lay public, as well as governments, who prefer simplicity to reality.  This situation, note the editors of this remarkable and very timely volume, may force science to abandon its efforts to explain and instead focus on introducing the least expensive methods of CO2 emission abatement (to the delight of a hopeful CO2 sequestration industry).

This unusually lengthy review highlights some of the most essential observations and conclusions of the papers presented as they relate to the current debate on climate change.  The intent has been to present a cohesive view of the purported warming phenomenon afforded by the generous amount of relevant, factual and refreshingly new information provided in this single volume.

THE CLIMATE DRIVERS
[Introduction and Overview, Chapters 2 and 4]

The book organizes the drivers of climate change into four categories.

First order controls include solar system geometry, solar luminosity and Earth's atmosphere, which evolved over the past 4.5 billion years and makes Earth's climate some 20 to 40°C warmer than it would otherwise be.

Second order controls are given by the distribution of oceans and continents, which determines the heat-distributing characteristics of ocean currents.  These controls explain the 15 to 20°C variations over periods of up to hundreds of millions of years.  Massive climate changes occurred in the distant past when continental drift obstructed equatorial currents, forcing warm surface water to be diverted to low latitudes and triggering an icehouse state such as the one we are in now. In late Cretaceous, some 90 million years ago, there was no land obstacle to fully developed equatorial currents and the planet was in a greenhouse state with atmospheric CO2 concentrations some three times higher than now.

At present, ocean currents provide a 'conveyor belt' of heat from equatorial regions to high latitudes where the saline water cools, builds density and finally descends into the deep ocean, forming a circumpolar deep current.  Any sudden change in the 'conveyor belt' configuration would likely have a drastic effect on climate.  Somewhat paradoxically, it is postulated that the onslaught of a new ice age will require further warming to melt more of the Arctic sea ice, allowing for more evaporation cooling and precipitation at high latitudes.  Such enhanced precipitation may interfere with the conveyor belt by diluting the salinity and density of the cold surface water layer and reversing its flow to provide cold surface currents in the direction of equatorial regions.  Such changes have massive and drastic effects on the planet's climate during periods of glaciation, as the falling temperatures allow for a quick build-up of sea ice, spreading to lower altitudes from polar regions over only several decades, quickly affecting the planet's albedo.  The steep temperature gradients between equatorial and polar regions make for storminess and additional aerosol cooling.  The effect of stopping the conveyor belt during an interglacial is more gradual, but nevertheless represents a real threat of drastic climate change.

Third order controls include Earth's orbital changes, solar variability, large-scale oceanographic oscillations and long ocean tide cycles, capable of causing temperature changes on the order of 5 to 15°C over centuries to hundreds of thousands of years, such as the roughly 100,000-year-long ice ages predictably occurring in concert with Earth's rythmic orbital changes, its changes in angle of rotation and its precessive movement.

Fourth order controls comprise a number of drivers affecting minor temperature changes of as much as 5°C over periods of several centuries or less.  El Niño/La Niña, volcanic eruptions, meteorite impacts and changes in solar activity are the natural drivers in this category; arguably, one might also list anthropogenic emissions of greenhouse gases (CH4 and CO2) here as well.

The fourth order controls are the ones of relevance to the present brief warming trend, and the two culprits thought most likely to be at work in this regard are variations in solar irradiance (solar forcing) and anthropogenic emissions (CO2 forcing).

ANCIENT CLIMATE AND RECENT CLIMATE
[Chapters 5, 10, 11 and 18]

Anyone suffering from the notion that Earth's climate was always stable and benign in the past would do well to study ancient global temperatures and their variations over the past millennium.

The environmentalist movement and advocacy groups along with the IPCC have convinced the public and politicians that Earth's temperature is on the rise, which is entirely correct if 1860 is chosen as the starting point.  The trend since 1300 AD, and more so since 3000 BC, is one of declining temperature.  Climate changes all the time.  Adapting to a slow rise in temperature is a more attractive alternative than having to deal with a cooling trend, stability not being an option.  Misconceptions of past conditions have influenced environmental language; terms such as 'sustainability', 'balance' and 'optimum' all refer to a biogeographical situation in equilibrium.  As no such equilibrium has ever existed, terms such as 'adaption', 'opportunism', 'flexibility' and 'resilience' would be more useful in describing human activities in an ever-changing environment.  Attempts to preserve an assumed equilibrium are by definition doomed to fail.

Three particularly illuminating time windows are presented to provide a perspective on the IPCC's climate predictions; the past 150,000, 10,000 and 1,000 years.  The longest period indicates that the planet is soon due for a substantial temperature drop with a return to near-current temperatures likely to occur more than 100,000 years into the future.  The shorter time windows presented provide evidence of a frequent series of temperature maxima and minima of smaller amplitude, with a substantial peak roughly 4000 - 3000 BC, a smaller one 1000 to1300 AD and a significant minimum around 1700 AD from which the planet has been recovering since the middle of the 19th century, to produce yet another natural temperature maximum, slightly lower than the last, 700 years ago.  The global warming scaremongers disagree, however, asserting that anthropogenic emissions of greenhouse gas contribute to the natural warming to an extent that overpowers natural climate drivers.

A unique temperature record from a lowland location in central England dating back to 1659 clearly shows the planet's slow recovery from the Little Ice Age, which culminated some 30 years after measurements began, plus the continuous slow warming that visibly accelerated very slightly in the second half of the 19th century.  The record illustrates the effect of natural drivers, for fossil energy emissions were woefully small during the 19th century and did not really begin accelerating significantly until after World War II, during a 30-year period that saw a moderate global temperature decline of 0.15°C.  This record, kept where the Industrial Revolution began, seems not to show any discernible impact of anthropogenic greenhouse gas emissions.

The rate and magnitude of the present warming has been described as unique and unprecedented.  However, isotope studies [¹⁸O] based on polar ice cores clearly indicate prior trends and patterns similar to those observed by direct measurement over the past 140 years, a period too short to be statistically significant and yet one that the IPCC claims to have 'matched' its models to.  The climate change since 1860 is neither unique nor unusual in a historical perspective of natural variation, and fully to be expected after a preceding natural cold spell.

The IPCC models would be far more convincing if they could be 'matched to' climate changes in the more distant past, including both cooling and warming periods.  However, they cannot.  The short term climate changes occurring over decades to millennia prior to the Industrial Revolution were caused by solar irradiation variations with ensuing changes in the planet's albedo (surface snow cover and atmospheric moisture, dust and cloud cover) and ocean circulation.  Such changes brought about the recovery from the Little Ice Age.  CO2 emissions have occurred on a serious scale for only about half a century, and any possible effects of these additions to the atmosphere must be seen in the context of ongoing natural changes that seem to have overwhelmed any effects the emissions may have had.

ATMOSPHERIC CO2
[Chapters 3 and 9]

Not only is there a popular belief that the global temperature has been stable in the past, even a 'majority of scientists' assert there has been a stable 'preindustrial' atmospheric CO2 level of some 280 ppm since the end of the past Ice Age 10,000 years ago, which allegedly (and in wholly unprecedented fashion) has jumped to the present 370 ppm as a result of industrialization and man's destruction of CO2-absorbing forests over the past 150 years.  Even the rate of 65 ppm in a century is considered unique.

The accepted interpretation of the CO2 increase does not consider degassing of the oceans to be a major source of atmospheric CO2.  The revelation that ancient temperature peaks coincided with increased atmospheric CO2 levels - with atmospheric chemistry changes following temperature change [Science, Vol. 291, p. 112, January 5, 2001] - has not received the attention it deserves.  The rapid accumulation of atmospheric CO2 since 1940 is conventionally considered to be largely due to emissions, which are said to have caused the present warming, 80% of which was completed before 1940.  The warming during the past decade, although seemingly out of step even with solar forcing was simply due to the absence of Siberian inversions causing extreme cold in the winter.  Unusual, localized wind patterns were to blame, not a fully global temperature increase.

The perplexing fact that the pronounced global temperature peak in 1940 coincided with a negative rate of CO2 accumulation in the atmosphere is normally avoided, but should not be.  It serves as a shining example of solar-induced warming with a simultaneous enhancement of carbon sequestration in more abundantly growing biomass dominating planetary carbon exchange.

Solar-induced warming and cooling periods ought to have produced significant changes in atmospheric CO2 levels over the past 10,000 years as a result of ocean degassing; yet the official record asserts a steady 'preindustrial' level.  Whereas the polar ice core record is highly reliable for past temperature determination, it is highly uncertain when it comes to the history of atmospheric CO2.  The ¹⁸O isotope stays locked in the ice; the CO2 record, however is blurred by carbon dioxide's redistribution in the salty brine of the ice and by data selection, with data deviating from the expected 'preindustrial' level tending to be discarded.

A new, robust technique to determine past CO2 levels was introduced in the late 1990s.  The inverse relationship between stomatal frequency in angiosperm leaves and ambient atmospheric CO2 concentration makes it possible to determine ancient CO2 levels from fossil leaves.  More recent levels can be read from leaves retrieved from peat bogs with excellent resolution.  Although absent in the ice core analysis results, this technique shows how atmospheric CO2 concentrations quickly rose from 260 ppm at the end of the latest Ice Age to 335 ppm in Preboreal times, declined again to some 300 ppm and reached 365 ppm 9,300 years ago.  These observations destroy the concept of a stable 'preindustrial' atmosphere and demonstrate how CO2 levels such as those of the present are the result of solar-induced temperature increases with ensuing ocean degassing.  Reconstructed events occurring over 9,000 years ago provide evidence of atmospheric CO2 increases at a rate of 65 ppm per century, resulting in CO2 levels close to the present at temperatures equally close to the present.  It is evident that one looks for telltale signs of effects of industrial emissions in vain.  Neither the present temperature, nor current atmospheric chemistry, show anomalies.

ANTHROPOGENIC WARMING UNLIKELY
[Chapter 17]

The greenhouse hypothesis has failed to even predict the past.  Observed increases in atmospheric CO2 since 1957 should have caused significantly greater temperature increases than those observed.  To explain this discrepancy, it is claimed that industrial aerosols provide sufficient cooling to limit the temperature increase resulting from man-made CO2 forcing.  Since the Clean Air Acts of the past three decades severely limited emissions from industrial processes with no observed resumption of a warming trend along the lines predicted, one might conclude there is a problem with the hypothesis.

This circumstance lends credibility to the notion that a massive increase in atmospheric CO2 does not lead to a large temperature increase as predicted by the IPCC models.  The reasoning is very straightforward; there is simply no compelling reason to believe that all feedback mechanisms operating as a result of the change in atmospheric chemistry should be positive.  If they were, Earth's climate could not possibly be as relatively stable as it is.  Sherwood Idso determined the temperature effect of a doubling of the atmospheric CO2 concentration and arrived at an expected temperature increase of a mere 0.4°C, a number which was confirmed performing several independent natural experiments - including CO2 forcing on Venus and Mars - all based on actual, measured data.  The IPCC predicts 1.5 to 4.0°C.

Idso's results lead to a compelling observation.  The 75 ppm increase in atmospheric CO2 since the end of the 19th century coincided with a warming that exceeded 0.4°C, which should have required a CO2 increase in excess of 300 ppm according to his analysis.  That conclusion implies that the observed warming was not primarily caused by the increase in atmospheric CO2.  Indeed, it appears fully possible it was due to changes in the sun's output, the major determinant of Earth's climate.  This conclusion is further reinforced by the observation that even a 0.4°C warming is in all probability an overestimate of Earth's climatic response to a 300-ppm increase in atmospheric CO2 concentration.  Any such warming is likely to increase cloud formation, for example; and biological processes stimulated by the increased CO2 concentration would also produce increased amounts of cloud condensation nuclei that would lead to increases in the planet's albedo, with a mere 0.1 to 0.3% increase in this parameter being fully capable of totally nullifying the CO2-induced temperature increase.

SOLAR FORCING
[Chapters1 and 10]

Contrary to the 'majority view,' there is a strong case for stating that the temperature changes observed in the past two centuries are solar-induced with resulting increases in atmospheric CO2 levels.  As in the ancient past, CO2 follows temperature and provides some positive feedback, most of which tends to be offset by natural negative feedback mechanisms.

Solar forcing is a direct result of variations in the solar energy flux reaching Earth's surface.  The sun dictates the climate, and its output is not anywhere near constant.  Variables relevant to the present warming include total solar irradiance (TSI), ultraviolet radiation and solar wind.  Sunspot cycles, reflecting TSI, vary in duration (7 to 17 years), amplitude, and numbers of spots.  TSI solar forcing alone accounts for 71% of the changes in mean global temperature between 1880 and 1993.

Solar-driven magnetic storms correlate closely with increased TSI.  They deflect some of the cosmic background radiation and lead to the clear variations in ¹⁰Be and ¹⁴C concentrations found in tree rings and ice cores.  The ¹⁴C record is somewhat smeared by the effect of ocean outgassing during warm spells, which leads to an elevated CO2 level; but ¹⁰Be serves as an excellent proxy, showing clear correlation between TSI and the high and low temperatures of the Medieval Warm period (1000 - 1300 AD) and the Little Ice Age (1400 - 1800 AD).

This solar forcing of climate was confirmed in the 1990s.  The period 1880 - 2000 shows a direct relationship between solar activity and temperature, with temperature following solar activity through all breaking points, maxima and minima.  CO2 forcing predicts a continuously increasing temperature, since emissions have increased continuously over this period: but that is not what has been observed.

The solar wind and increased UV-radiation associated with elevated TSI also contribute to temperature change.  The solar wind deflects galactic background radiation, diminishing the rate of cloud formation by reducing the presence of needed condensation nuclei.  This effect is especially pronounced in low latitudes and results in a net warming of the Earth.  The 3 to 4% variation in cloud cover over an average 11-year solar cycle produces a net radiative variation of 1.7 Wm^-2, which is more than the 1.56 Wm^-2 change calculated for CO2 forcing since 1750 AD.  The solar wind velocities explain all the temperature changes from 1900 to 1950, including the peak in 1939 - 1941, which CO2 forcing is at a loss to rationalize.

The TSI variations are stronger for the shorter wavelength radiation emanating from the sun.  Ultraviolet radiation is more intensified than visible light, leading to a warming of the stratosphere by increasing the ozone concentration and enhanced absorption of UVB.  The warming forces tropospheric circulation patterns poleward.  It is reasonable to postulate that this mechanism was responsible for the absence of extreme cold-producing inversions in Siberia, which alone was responsible for the mean global temperature increase of the past decade.

Ascribing atmospheric CO2 level changes to anthropogenic CO2 emissions is clearly incorrect, as atmospheric CO2 increases result from increasing sea surface temperatures (SST).  A TSI variation of 0.6% since 1860 should have produced the observed increase in SST and is perfectly commensurate with the -1% variation during the peak of the Little Ice Age.  Atmospheric CO2 increase should therefore be viewed as a third sun-induced indirect effect on global temperature, following slightly behind an elevated TSI and the associated enhancement of solar wind and UV-radiation.  The role of CO2 emissions is simply to reduce the amount of CO2 which would be released from the ocean as a result of increasing ocean surface temperature in the absence of emissions.  Hence, one would expect the current temperature to remain within natural ranges, which is the case.  The present temperature and atmospheric CO2 levels are entirely in accord with data acquired from the early Holocene using the stomatal frequency method to determine atmospheric chemistry and ¹⁸O analyses from polar ice caps to determine temperature.

The author of the solar forcing paper, Alfred H. Pekarek, concludes somewhat modestly that TSI variations are responsible for "much, perhaps all" of the current warming and states that "drastic measures are certainly not advisable to solve a problem that may not exist."

One would fervently hope that the vital information contained in this important volume is carefully digested by the media and those wielding political power, thus helping to end a fruitless debate where acquired beliefs and false prophets mingle with ease, leaving the truth of the matter at a comfortable distance.