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Global Warming's Omitted Variables
by Alec Rawls
In late January, a spate of alarming global-warming reports hit the newspapers. The International Climate Change Taskforce warned that warming is likely to hit a “point of no return” within ten years. The World Wildlife Fund also warned of imminent climate “tipping.” Climateprediction.net announced that, by testing a wider variety of initial conditions than other climate modelers, it had arrived at a more radical range of warming predictions.
All of these studies employ the classic ruse of advocacy statistics: they omit key explanatory variables, so that explanatory power gets misattributed to those explanatory variables that are included. The variable that these studies leave out is the solar-magnetic flux. As a result, the warming caused by high levels of solar-wind over the last half century gets misattributed to greenhouse gases. This exaggerated greenhouse effect then gets projected forward into trumped-up predictions of imminent catastrophe if human production of greenhouse gases is not drastically curtailed.
Sunspots and climate
Correlation between sunspot activity and cloudless skies has been observed for over a century. It is also known that the Little Ice Age coincided with a sunspot minimum. What has been a mystery is the mechanism by which solar activity affects climate. In the last decade, scientists have finally begun to solve this riddle. Solar flares generate storms of solar magnetic flux that partially shield the Earth from cosmic radiation. Cosmic radiation ionizes the atmosphere, which seems to promote cloud formation. Thus high levels of solar wind have the effect of blowing away the cloud cover, giving the Earth a sunburn. Solar activity has been very high since the 1940’s, so the slight global warming observed since the mid 70’s could easily be due to this effect.
None of the global warming alarmists take this effect into account. All of the recent alarmist studies are based on the GCMs (General Circulation Models) employed by the IPCC (the International Panel on Climate Change). These IPCC GCMs have never included the effects of cosmic rays on cloud formation. Back in 1996, at the time of the IPCC’s Second Assessment Report, this omission was marginally tenable. Sunspots generate a slight increase in solar luminosity (the cooler spots are surrounded by super-hot “faculae”) but this increase in radiance is not enough to create significant global warming. The correlation between sunspots and cloudiness was also known, but since no one had any idea what the causal link might be, they did not built it into their models.
The intensity of the Sun varies along with the 11-year sunspot cycle. When sunspots are numerous the solar constant is high (about 1367 W/m2); when sunspots are scarce the value is low (about 1365 W/m2). Eleven years isn't the only "beat," however. The solar constant can fluctuate by ~0.1% over days and weeks as sunspots grow and dissipate. The solar constant also drifts by 0.2% to 0.6% over many centuries, according to scientists who study tree rings.
These small changes can affect Earth in a big way. For example, between 1645 and 1715 (a period astronomers call the "Maunder Minimum") the sunspot cycle stopped; the face of the Sun was nearly blank for 70 years. At the same time Europe was hit by an extraordinary cold spell: the Thames River in London froze, glaciers advanced in the Alps, and northern sea ice increased. An earlier centuries-long surge in solar activity (inferred from studies of tree rings) had the opposite effect: Vikings were able to settle the thawed-out coast of Greenland in the 980s, and even grow enough wheat there to export the surplus to Scandinavia.
Above: Inferred variations in solar intensity (red and green lines) over the last 900 years appear to be related to the severity of winters in London and Paris. The red line is deduced from the abundance of a heavy form of carbon (carbon-14) in tree rings. This "isotope" of carbon is formed in the upper atmosphere when incoming cosmic rays smash into carbon dioxide molecules. When the Sun's activity is low, its weakened magnetic field lets more cosmic rays into the solar system, so carbon-14 abundances go up. (Notice on the graph that the scale for carbon-14 is upside down.) This image by scientist John Eddy is based on an earlier one that appeared in Science, 192, 1189 (1976).
Originally posted by Muaddib
Earth's magnetic field is fading. Today it is about 10 percent weaker than it was when German mathematician Carl Friedrich Gauss started keeping tabs on it in 1845, scientists say.
Originally posted by Nygdan
But please explain, why is it that CO2 emissions can't account for the global temperature increase, but sunspot activity can? Especially given that the CO2 emissions are coincident with the temperature increase?
Water Vapor Rules
the Greenhouse System
Just how much of the "Greenhouse Effect" is caused by human activity?
It is about 0.28%, if water vapor is taken into account-- about 5.53%, if not.
This point is so crucial to the debate over global warming that how water vapor is or isn't factored into an analysis of Earth's greenhouse gases makes the difference between describing a significant human contribution to the greenhouse effect, or a negligible one.
Water vapor constitutes Earth's most significant greenhouse gas, accounting for about 95% of Earth's greenhouse effect (4). Interestingly, many "facts and figures' regarding global warming completely ignore the powerful effects of water vapor in the greenhouse system, carelessly (perhaps, deliberately) overstating human impacts as much as 20-fold.
Water vapor is 99.999% of natural origin. Other atmospheric greenhouse gases, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and miscellaneous other gases (CFC's, etc.), are also mostly of natural origin (except for the latter, which is mostly anthropogenic).
Russian academic says CO2 not to blame for global warming
14:30 | 15/ 01/ 2007
ST. PETERSBURG, January 15 (RIA Novosti) - Rising levels of carbon dioxide and other gases emitted through human activities, believed by scientists to trap heat in the Earth's atmosphere, are an effect rather than the cause of global warming, a prominent Russian scientist said Monday.
Habibullo Abdusamatov, head of the space research laboratory at the St. Petersburg-based Pulkovo Observatory, said global warming stems from an increase in the sun's activity. His view contradicts the international scientific consensus that climate change is attributable to the emission of greenhouse gases generated by industrial activities, such as the burning of fossil fuels and deforestation.
"Global warming results not from the emission of greenhouse gases into the atmosphere, but from an unusually high level of solar radiation and a lengthy - almost throughout the last century - growth in its intensity," Abdusamatov told RIA Novosti in an interview.
"It is no secret that when they go up, temperatures in the world's oceans trigger the emission of large amounts of carbon dioxide into the atmosphere. So the common view that man's industrial activity is a deciding factor in global warming has emerged from a misinterpretation of cause and effect relations."
The Intergovernmental Panel on Climate Change, a UN panel of thousands of international scientists, widely regarded as an authority on climate change issues, established a consensus many years ago that most of the warming experienced over the last half-century has been attributable to human activities.
However, scientists acknowledge that rises in temperatures can potentially cause massive increases of greenhouse gases due to various natural positive feedback mechanisms, for example the methane released by melting permafrost, ocean algae's reduced capacity to absorb carbon at higher water temperatures, and the carbon released by trees when forests dry up.
Abdusamatov, a doctor of mathematics and physics, is one of a small number of scientists around the world who continue to contest the view of the IPCC, the national science academies of the G8 nations, and other prominent scientific bodies.
He said an examination of ice cores from wells over three kilometers (1.5 miles) deep in Greenland and the Antarctic indicates that the Earth experienced periods of global warming even before the industrial age (which began two hundred years ago).
Originally posted by Nygdan
That is not continuously high and that pattern does not match the global warming pattern.
This graph asserts that temperatures during the Medieval Warm Period were higher than those of today (as suggested by the opening lines to the Canterbury Tales by Geoffrey Chaucer), while it was much cooler during the Little Ice Age (as suggested by John King). Historical records from all over Europe, and Greenland attest to the reality of both events, and their profound impact on human society. For example, the colonisation of Greenland by the Vikings early in the millennium was only possible because of the medieval warmth. During the Little Ice Age, the Viking colonies in Greenland collapsed, while the River Thames in London often froze over, resulting in frequent `frost fairs' being held on the river ice.
The dating of these two climatic events depends to some extent on what one regards as `warm' and `cold' in comparison with present temperatures, but the following dating approximates these events -
1) `Medieval Warm Period' (AD 700 - 1300)
2) `Sporer Minimum' cool period (AD 1300 - 1500)
3) Brief climatic warming (AD 1500 - 1560)
4) `Little Ice Age' (`Maunder Minimum') (AD 1560 - 1830)
5) Brief warmer period (AD 1830 - 1870)
6) Brief cool period (AD 1870 - 1910)
7) 20th century warm period (AD 1910 - 2000)
Dr Michael Mann of the Department of Geosciences, University of Massachusetts was the primary author of the GRL paper, and in one scientific coup overturned the whole of climate history .
Using tree rings as a basis for assessing past temperature changes back to the year 1,000 AD, supplemented by other proxies from more recent centuries, Mann completely redrew the history, turning the Medieval Warm Period and Little Ice Age into non-events, consigned to a kind of Orwellian `memory hole' . Fig.4 shows Mann's revision of the climatic history of the last millennium.
A missing link in climate theory
The experimental results lend strong empirical support to the theory proposed a decade ago by Henrik Svensmark and Eigil Friis-Christensen that cosmic rays influence Earth's climate through their effect on cloud formation.
The original theory rested on data showing a strong correlation between variation in the intensity of cosmic radiation penetrating the atmosphere and the amount of low-altitude clouds. Cloud cover increases when the intensity of cosmic rays grows and decreases when the intensity declines.
It is known that low-altitude clouds have an overall cooling effect on the Earth's surface. Hence, variations in cloud cover caused by cosmic rays can change the surface temperature. The existence of such a cosmic connection to Earth's climate might thus help to explain past and present variations in Earth's climate.
Interestingly, during the 20th Century, the Sun's magnetic field which shields Earth from cosmic rays more than doubled, thereby reducing the average influx of cosmic rays.
The resulting reduction in cloudiness, especially of low-altitude clouds, may be a significant factor in the global warming Earth has undergone during the last century. However, until now, there has been no experimental evidence of how the causal mechanism linking cosmic rays and cloud formation may work.
"Many climate scientists have considered the linkages from cosmic rays to clouds to climate as unproven," comments Eigil Friis-Christensen, who is now Director of the Danish National Space Center.
"Some said there was no conceivable way in which cosmic rays could influence cloud cover. The SKY experiment now shows how they do so, and should help to put the cosmic-ray connection firmly onto the agenda of international climate research."
The following picture (additions by meteoLCD) shows the influence of CGR's on low (but not higher!) cloud cover; these low clouds are responsible for shielding from the sun and cooling the earth. During the last 100 years the event sequence "high solar activity --> fewer CGRs --> fewer low clouds --> lesser cooling = more warming" might explain 1.2 W/m2 of the 1.4 W/m2 forcing attributed by the IPCC to man-made greenhouse gases!