Let’s face it. The earth is warming. It has been warming steadily — though with some short-term variation and even some prolonged cooling periods — for at least the last 12,000 years. Students of astronomy, geology and physical anthropology are well aware of the planet’s slow but regular warming and cooling cycles.
Between the onset of the glacial expansion about 35,000 years ago and when the current round of global warming began again, sea level had dropped 450 feet and the Virginia shore line extended about 60 miles East of its present location, according to one account of the region’s geology. The Sahara Desert was once grassland before the formation of massive sand dunes, and rising waters have reclaimed much of the ancient world’s storied coastlines, including Peloponnesia. The ancient port of Cenchreai, from which St. Paul sailed to the island of Ephesos — submerged before the beginning of the Industrial Revolution — is still visible in aerial photographs.
Naturally occurring cycles
Water will likely continue to rise over the world’s coastal properties and cities regardless of what portion of the warming is anthropogenic (of man-made causes).
However, public discussions of global warming are rarely framed (outside the temples of science) in the context of the naturally occurring cycles that many scientists are still trying to fully understand. A Nexis search, for example, quickly reveals that many people believe or disbelieve in global warming (forget the nuance of the anthropogenic component), and that many of those who do, also believe that it can be stopped — by implication, then, that they can stop the eon-scale forces of nature.
In fact, some scientists are beginning to attribute Earth’s warming and cooling trends to sunspot activity, pointing to the correlation of sunspots and solar energy output to terrestrial temperature.
The alarmist propaganda that has driven the climate-change discussion — and U.S. environmental policy — for the last 20 years continues to confuse the global-warming discussion, especially the extent of the contribution of its anthropogenic component. That confusion will no doubt be a factor in December’s Copenhagen Conference at which negotiators will promulgate a successor to the 1997 Kyoto Protocol to control the emission of so-called greenhouse gasses, which the United States, a signatory, did not ratify.
The growing number of skeptics of the anthropogenic global-warming argument — as it has been framed — may also be a factor. A Senate Environment and Public Works Committee Minority Report released Dec. 11, 2008, listed more than 400 U.S. and international scientists challenging “man-made global-warming claims” by the United Nations Intergovernmental Panel on Climate Change (IPCC) and former Vice President Al Gore. The number of scientist skeptics has grown to more than 700 today, and much of that skepticism focuses on the importance of naturally occurring cycles.
Sunspots, weather and climate
While scientists have speculated for more than a century about how sunspot-related solar radiation streaming toward Earth affects our weather, a paper published recently (August 27) in the journal Science demonstrates how sunspot activity can produce La Niña and El Niño-like conditions over the globe’s tropical oceans.
That research, a synthesis of three computer models and more than a century of observational data, describes a new weather model in which sunspot activity tracks with measured weather patterns, but beyond emphasizing the role of sunspots, offers no implication for global warming. That may be found elsewhere.
Dr. John M. Davis, with the NASA/Marshall Space Flight Center Solar Physics Team confirmed New York Times reports by science writer Kenneth Chang that sunspot activity over the last year and a half has been much lower than expected — no sunspots visible for 266 days in 2008 and a similar performance so far in 2009. While there were a few sunspots in July, there have been none as of August 27, Davis said.
The National Oceanic and Atmospheric Administration currently predicts a maximum of 90 sunspots for the coming 2013 solar maximum, 30 sunspots off the event’s average.
The current prolonged low output of sunspots, what Davis calls an extended minimum, is not out of character with what is known about sunspot activity, but was not predicted, he said, which is why it is generating a buzz. “There’s a lot we don’t understand,” he said, noting the complexities involved and that some other stars similar to the sun in size and age do not produce spots. Davis does not cross the line into the global-warming discussion, but he recognizes that a lack of sunspots results in a cooler climate.
Astronomy textbooks charting the sunspot record beginning with the earliest European recording of the phenomenon by Thomas Harriot in 1610, show a less-than-predictable record of sunspot output. Between 1645 and 1715, sunspot activity was almost non-existent. That period known, as the Maunder Minimum, coincided with a European cold spell referred to as the “Little Ice Age.” Norman Davies in his History of Europe (Oxford University Press, 1996) says that “Periods of glacial maxima peaked in 1599-1600, 1640-1650, 1680, 1716-1620 and 1770.”
Scientists have been trying for many years to understand how and why the Earth warms and cools on a cyclical basis and, even more to the point, how to predict when it will do either. Cyclical planetary and solar occurrences other than sunspots have also been the focus of many of their inquiries. For example, the Earth’s orbit changes shape over a 93,000-year period. The orbit varies from being more elliptical, with a potential to contribute to cooling as Earth passes farther from the sun for longer periods, to more circular, with the potential to contribute to warming, according to astronomer Michael A. Seeds.
The Earth wobbles, too, a phenomenon called precession. The wobble completes one cycle every 26,000 years. At one point in the wobble, the rotational North Pole points to Polaris, as it does today, 13,000 years later the pole will point roughly to Vega before returning again to Polaris.
As Earth wobbles, its tilt varies. It is now at angle of 23.5 degrees, but the tilt ranges from 22 degrees to 28 degrees over a period of about 41,000 years. As every fifth grader knows, the tilt coupled with the Earth’s revolution around the sun accounts for the seasons.
There’s more. Just as the sun’s magnetic field reverses polarity a year or two after its maximum sunspot output, Earth’s magnetic field also reverses polarity, though less frequently. In other words, the Earth’s magnetic North and South poles trade positions. They “have reversed polarity nine times in the past 3.5 million years,” according to an astronomy textbook by Michael Zeilik. The magnetospheres of both bodies interact and affect weather and climate. Other geological phenomena, including volcanic eruptions, will also affect climate.
“In 1653, local people defiantly placed a statue of St. Ignatius at the base of the [expanding] Aletsch glacier; and the glacier stopped. The contemporary glacial retreat has continued since 1850,” says historian Davies. Whether advocates of the anthropogenic global-warming view and their interest groups can stop global warming, as they claim, remains to be seen, despite what the advocates of anthropogenic global-warming say.