Six years ago, the U.N.'s Intergovernmental Panel on Climate Change published a much criticized report that included a number of significant errors.  Now the IPCC's climate activists -- er, scientists -- want us to believe they've cleaned up their act.  But even their summary report released on Friday raises questions.

Last time, the IPCC reported that there was a 90% chance that human activity was affecting the climate.  Now they've upped that to 95%.  The report offers a detailed and, to the non-specialist reader, impenetrable rationale for this change, but to my mind, these figures sound all too much like the old toothpaste commercial.  The "new and improved" product prevents 95% of all cavities -- the old toothpaste prevented only 90%.  Buy the "new and improved."

Over the past 15 years, the IPCC itself suggests that natural forces, such as volcanic eruptions, have overridden human activity so that warming has slowed or "plateaued."  So just how much influence does human activity have, if any, when weighed against natural and cyclical forces?  Is it worth turning the entire global economy over to the climate alarmists just to rein in human activity that has been shown to have no effect on the earth's climate when weighed against natural forces?

Expanding the powers of government is precisely what is at stake in the battle over climate change.  The 2013 IPCC report will serve as fodder for the EPA and other agencies to intensify their war on coal and other carbon energy sources.  But just as the "science" of eugenics served as the foundation for the destruction of liberty in an earlier era, climate "science" has the potential of robbing the earth's peoples of their liberty today.

By the way, what is the IPCC?  It is a panel operating under the auspices of the United Nations.  While claiming that its work is "never policy-prescriptive," the IPCC in its latest report alludes to the role of "energy" and other industries in relation to carbon emissions and asserts that it is "likely" or "highly likely" that man-made carbon emissions at current levels will lead to devastating consequences by the end of this century, if not earlier.  In what sense is this not "policy-prescriptive"?  And while the panel claims to "reflect a range of views," does the panel include a single major scientist who doubts the existence of man-made global warming?  If so, I have overlooked the name.

The 2013 report appears at an awkward time for climate activists, since it appears certain that the earth's surface climate is no longer warming.  The IPCC report itself documents Northern Hemisphere Spring Snow Cover to now be greater than it was in 1990.  It is also greater than it was in the late 1960s.  In fact, it is at the same level measured in the early 1920s.  All the IPCC can say about this trend is that "the earth is continuing to take up heat even when the surface is warming slowly."  Except that, by many accounts, the surface is not "warming slowly"; it is cooling.

Then there is the line about how the Earth has been warmer over the past few decades than at any time since 1850, and anthropogenic causes are to blame.  But if human factors are driving the warming today, what was the cause of even greater warming in 1850, when anthropogenic forces were vastly less in play?

One of the more ominous aspects of the IPCC report is the assertion that "net land use" has been an important factor in increased carbon emissions.  Even if this were so, is the IPCC suggesting that less land be used for activities such as growing food?  Any significant reduction in land use for crop production would lead to hunger for the one billion human beings living at the bottom of the socioeconomic order.  It's astounding that the IPCC report can raise the question of land use without even alluding to the fact that increased "net land use" since pre-industrial times has led to an unprecedented increase in human living standards, and that any significant reduction of land use will reduce those living standards. 

The IPCC report repeatedly refers to the need to prevent climate change, but it fails to consider two fundamental questions: why should human beings attempt to prevent the climate from changing?  And can they prevent the climate from changing, even if they try? 

A more balanced report on climate change would note the actual facts that the Earth's temperatures have risen only mildly since 1850, less so than at many times in past millennia; that the effects of this increase in temperature, whether man-made or not, have not been catastrophic (and many, such as the opening of an arctic passage for shipping, have been positive); that the oceans have not risen catastrophically, as predicted by climate scientists in the past (even the latest report predicts under one scenario as little as a one-foot increase by 2100); and that hurricanes have not ravished America's coasts, as climate alarmists predicted in 2007 (the IPPC report now has "low confidence" that tropical storms will increase globally).  The fact is that for ordinary citizens, climate change hasn't had much impact except insofar as governments have imposed regulation of energy markets leading to higher fuel and electricity costs.

That is another matter that seems to be missing from the IPCC report.  The IPCC believes that the use of fossil fuels "may be" responsible for much of the warming that has taken place in the recent past.  At current levels of global carbon emissions, there is a "chance" of a two-degree-Celsius increase in the Earth's temperatures by 2040 or 2050, according to one of the report's lead authors.

That may very well be.  It may also very well be that natural forces, cyclical in nature, are more powerful than man-made influences and that these forces will balance out whatever effect human behavior has on the Earth's temperatures.  Or it may be that temperatures will rise, and that this increase will be beneficial.  But one thing is certain: more regulation will lead to higher energy costs, lower economic growth, and a reduced standard of living.

It would seem that a full and balanced report on climate change ought to include a cost-benefit analysis of global climate policies.  A trillion dollars squandered on the restriction of carbon emissions -- spending that might or might not reduce future warming -- would have a dramatic effect on global growth if allowed to remain invested in the private economy.  A small increase in global temperatures, an outcome still speculative in nature, would probably have no significant impact on the lives of ordinary human beings.  But one trillion dollars invested in the private sector would dramatically alter life on earth, and for the better.

Given the choice between greater economic growth and the mere possibility of a small increase in global temperatures, I would choose growth every time.

Jeffrey Folks is the author of many books on American politics and culture, including Heartland of the Imagination (2011).