20 Years Ago: 4-22-93 — John Christy says dire reports of global warming not based on reliable data; Satellite data show no warming

From the days when a skeptic could get published in the MSM — here, the Atlanta Journal-Constitution. Christy offers a good overview of the satellite monitoring system he and Roy Spencer developed.

The article is below.


Dire reports of global warming may not be based on reliable data
April 22, 1993, Atlanta Journal and Constitution

HUNTSVILLE, Ala. – The Philippine volcano Mount Pinatubo threw a curve to climate watchers around the world: Just when reports of global warming and its terrible consequences were becoming standard fare, the global temperature dropped by an amount equal to a quarter-century of the predicted warming.

Forecasts of a Midwestern desert or of melted polar icecaps flooding coastal cities in the 21st century are more difficult to accept these days when we’ve just experienced the Blizzard of ’93.

But how reliable are the data used to support claims of warming due to the enhanced greenhouse effect?

Earth’s atmosphere includes some gasses which have distinctive trait: They let sunlight pass through to heat Earth’s surface, but they capture energy that leaves this sun-warmed surface. These are called greenhouse gasses.

If more of these gasses were added to the air – and nothing else changed – the atmosphere would retain more heat. It would get warmer. If that were the case, global warming due to an “enhanced greenhouse effect” should occur.

The concentration of some greenhouse gasses, like carbon dioxide and methane, is increasing. There is really no debate on that issue. The debate arises from results expected for the real atmosphere, the behavior of which, scientists agree, contains great uncertainties.

Most of the world is not covered with regular thermometer readings. The “global temperature” from surface temperature measuring stations is, in reality, not global. It neglects vast regions, including most of the world’s oceans, Antarctica, and interiors of South America, Africa and Greenland.

There is another problem, too. Of great concern to scientists is the lack of consistency in the way readings are taken and in the thermometer surroundings. Since most thermometers for which long-term records exist are in towns and cities, the effects of population growth and the construction of nearby roads, parking lots, runways and buildings will cause the temperature to rise a little due to urbanization.

Are we really witnessing an “asphalt effect” instead of the greenhouse effect in these data? The best that can be said for the surface temperature is that over the last 100 years, one can see about a 1 degree Fahrenheit warming for those places that have thermometers.
A new method for measuring global temperatures was developed by Dr. Roy Spencer of NASA’s Marshall Space Flight Center and myself. We use satellites to record the “brightness temperature” of microwaves emitted by oxygen in the atmosphere. The key advantages of this method are:

– The satellite observes the entire Earth;
– Its thermometer is calibrated more than 3,000 times a day.
– Only one thermometer per satellite does the measuring, so there is no conflict with incompatible instruments.

The instruments which collect these data provide global temperature readings to an accuracy of about 0.04 degrees F per month. They have shown that the temperature of the entire globe, for the atmosphere from the surface up to about 16,000 feet, has experienced warm and cool periods, but there is no significant trend up or down since 1979. As of March 31, 1993, the 14 1/4-year trend was slightly downward.
In contrast, the surface record shows an upward trend of about 0.2 degrees F per decade in that same period. Before Mount Pinatubo exploded in June 1991, the surface data trend since 1979 was up almost 0.4 degrees F.

Even then, the satellites showed no significant trend at all.

There are many environmental problems – toxic waste disposal, water and air pollution, deforestation, ecological degradation, and overpopulation – that are immediate threats to our well being.

Evidence that global warming is an immediate threat has not been substantiated.

Someday, after a lot of research, we may finally know if the climate is changing. Let us hope we make the proper decisions along the way to mitigate real problems, and not perceived ones.

Dr. John Christy is an assistant professor of atmospheric science, and a global climate systems research scientist at the University of Alabama at Huntsville’s Earth Systems Science Laboratory. Dr. Christy and Dr. Roy Spencer received NASA’s Exceptional Achievement Medal for their work in developing a satellite-based system to measure air temperatures all over the planet.

2 thoughts on “20 Years Ago: 4-22-93 — John Christy says dire reports of global warming not based on reliable data; Satellite data show no warming”

  1. Roy and John had it right then, and they have it right now.

    No Thermageddon. More pressing global environmental issues.

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