How Accurate Have Global Warming Predictions Been So Far?

This is a reasonable question, is it not? After all, the heart of what differentiates experimental science (the kind that makes technology work) from other forms of human wisdom is that its theories make predictions that come true and are observed to do so.

So when the AGW alarmist crowd sternly proclaims that the "science is settled," I want to know first if it even is "science" and if it is not based on theories about the empirical world that make predictions that can be observed to come true then it is not science.

Fox News has a nice compilation of previous predictions made by environmental alarmists (alarmist = one who claims that we are in a crisis and must act immediately to avoid catastrophe). The same folks who today are predicting a 20 foot rise in the ocean levels as the polar ice caps melt have been in the prediction business for several decades now and since many of their predictions have short time frames (otherwise they would not be scary enough to motivate panicked action on the part of governments), we can now look back and evaluate objectively how good their track record is.

As George W. Bush said: "Fool me once, shame on you; fool me twice, shame on me."

Here are the first few predictions in the article out of the eight it highlights. (Many many more can be discovered using Google.)

1. Within a few years "children just aren't going to know what snow is." Snowfall will be "a very rare and exciting event." Dr. David Viner, senior research scientist at the climatic research unit (CRU) of the University of East Anglia, interviewed by the UK Independent, March 20, 2000.

Ten years later, in December 2009, London was hit by the heaviest snowfall seen in 20 years. And just last week, a snowstorm

forced Heathrow airport to shut down, stranding thousands of Christmas travelers.

2. "[By] 1995, the greenhouse effect would be desolating the heartlands of North America and Eurasia with horrific drought, causing crop failures and food riots…[By 1996] The Platte River of Nebraska would be dry, while a continent-wide black blizzard of prairie topsoil will stop traffic on interstates, strip paint from houses and shut down computers." Michael Oppenheimer, published in "Dead Heat," St. Martin's Press, 1990.

Oppenheimer told FoxNews.com that he was trying to illustrate one possible outcome of failing to curb emissions, not making a specific prediction. He added that the gist of his story had in fact come true, even if the events had not occurred in the U.S.

"On the whole I would stand by these predictions -- not predictions, sorry, scenarios -- as having at least in a general way actually come true," he said. "There's been extensive drought, devastating drought, in significant parts of the world. The fraction of the world that's in drought has increased over that period."

3. "Arctic specialist Bernt Balchen says a general warming trend over the North Pole is melting the polar ice cap and may produce an ice-free Arctic Ocean by the year 2000." Christian Science Monitor, June 8, 1972.

Ice coverage has fallen, though as of last month, the Arctic Ocean had 3.82 million square miles of ice cover -- an area larger than the continental United States -- according to The National Snow and Ice Data Center.

4. "Using computer models, researchers concluded that global warming would raise average annual temperatures nationwide two degrees by 2010." Associated Press, May 15, 1989.

Status of prediction: According to NASA, global temperature has increased by about 0.7 degrees Fahrenheit since 1989. And U.S. temperature has increased even less over the same period.

5. "By 1985, air pollution will have reduced the amount of sunlight reaching earth by one half." Life magazine, January 1970.

Life Magazine also noted that some people disagree, "but scientists have solid experimental and historical evidence to support each of the following predictions."

Air quality has actually improved since 1970. Studies find that sunlight reaching the Earth fell by somewhere between 3 and 5 percent over the period in question.

6. "If present trends continue, the world will be ... eleven degrees colder by the year 2000. This is about twice what it would take to put us in an ice age." Kenneth E.F. Watt, in "Earth Day," 1970.

According to NASA, global temperature has increased by about 1 degree Fahrenheit since 1970.

How could scientists have made such off-base claims? Dr. Paul Ehrlich, author of "The Population Bomb" and president of Stanford University's Center for Conservation Biology, told FoxNews.com that ideas about climate science changed a great deal in the the '70s and '80s.

"Present trends didn't continue," Ehrlich said of Watt's prediction. "There was considerable debate in the climatological community in the '60s about whether there would be cooling or warming … Discoveries in the '70s and '80s showed that the warming was going to be the overwhelming force."

Ehrlich told FoxNews.com that the consequences of future warming could be dire.

Read the rest here.

Well, it could be dire, Prof. Ehrlich. Then again, it could be benign or a net benefit. Or trends could reverse again like they did in the 70s and 80s and global cooling could be the "crisis de jour." We really don't know and neither do the alarmists.

If AGW were based on science and if it were reasonable to act on the predictions of the IPCC alarmist crowd, then their past predictions would not be so utterly and completely off base.