Earth is "on the brink of entering another Ice Age" that will last for the next 100,000 years, reports the Russian Pravda Online newspaper, attempting to counter the widespread view that human activity is contributing to an unwanted and dangerous warming of the planet.

Based on a "large and compelling body of evidence from within the field of climate science," Pravda reports this week, "many sources of data which provide our knowledge base of long-term climate change" indicate that the current 12,000-year-long warming trend is coming to an end.

Pravda points to three astronomical "Milankovich cycles" for the coming cool-down:

• The tilt of the Earth, which varies over a 41,000-year period.

• The shape of the Earth's orbit, which changes over a period of 100,000 years, "separated by intervening warm interglacials, each lasting about 12,000 years."

• The Precession of the Equinoxes, also known as the earth's "wobble," which gradually rotates the direction of the earth's axis over a period of 26,000 years.

Erik Brown, a professor of geological sciences at the University of Minnesota, Duluth, today characterized the report as telling a "rather sensational story."

"Certainly much of what is discussed regarding Milankovich cycles is essentially correct. However, a critically important point is that the conditions of the Earth's orbit about the Sun do not return to the exact same settings every 100,000 years. This leads to natural variability in the length of the warm interglacial periods."

Brown also disputed the report's implication that the observed increase in carbon dioxide over the past century "may be explained by natural processes, and is comparable to past variations."

"This is simply wrong," Brown said. "If you were to plot changes in CO2 [carbon dioxide] over the past century ... CO2 concentrations would increase ... well beyond levels in the past million years at a rate completely unlike anything seen in nature."

Steve Colman, a professor of biochemistry and geochemistry at the University of Minnesota in Minneapolis, characterizes Pravda's contentions as "just plain silly, mixing, as it does, vastly different time scales."

While acknowledging that the report "contains a kernel of truth" about the earth probably being "at the end of peak interglacial warmth and heading into the beginning of another Ice Age," Colman adds that "the amount of greenhouse gases we are contributing to the atmosphere, and the rate at which we are doing so, completely dwarfs the natural variations."

These Milankovich cycles, Pravda explains, each affect "the amount of solar radiation which reaches the Earth [and] act together to produce the cycle of cold Ice Age maximums."

Since the late 1970s, the Milankovich theory has remained a predominant explanation to account for Ice Age causation among climate scientists. Pravda then went on to outline the widespread campaign to counter so-called global warming and the prevailing thought that human activity is dangerously warming the planet.

"The main flaw" in the thinking behind global warming, Pravda says, "is that its proponents focus on evidence from only the past 1,000 years at most, while ignoring the evidence from the past million years -- evidence which is essential for a true understanding of climatology."

The data provide a "more credible explanation for the recent global temperature spike, based on the natural cycle of Ice Age maximums and interglacials."

Pravda predicts that the Earth is "near to the end of a warm interglacial, and the Earth is now due to enter the next Ice Age. If we are lucky, we may have a few years to prepare for it. The Ice Age will return, as it always has, in its regular and natural cycle, with or without any influence from the effects" of global warming.

Pravda was a leading newspaper of the Soviet Union and an official organ of the Central Committee of the Communist Party between 1912 and 1991. After the paper was closed in 1991 by government decree, many of the staff founded a new paper with the same name. Pravda Online is run by former Pravda newspaper employees.

Paul Walsh • 612-673-4482