Since then, the global mean temperature of the earth has not warmed a bit. Three independent measuring systems (and the only three that exist) — surface measured temperature, temperatures of the lower atmosphere measured by weather balloons, and temperature of the lower atmosphere measured by orbiting satellites‐all show no warming since that testimony (see Figure 1).[OMITTED]
Global Temperature Departures
In science, regardless of how much external political and social pressure is applied, it is inevitable that observed data and theoretical hypotheses will eventually reach an internally consistent equilibrium. However, it was apparent that when the first “consensus” was imposed on the issue of global warming, by the First Scientific Assessment of the United Nations Inter‐governmental Panel on Climate Change (1990), that such an equilibrium had not been reached.
That report stated that “when the latest atmospheric models are run with the present concentrations of greenhouse gases, their simulation of climate is generally realistic on large scales.” (1) The suite of climate models extant at the time predicted that the globe’s mean temperature should have risen by 1.3* to 2.3*, with the larger figure for the Northern Hemisphere, where most of us live. These models provided the technical background for the Framework Convention on Climate Change, signed in 1992.
The observed warming since the late 19th century was 0.5*, or less than one‐third of the predicted value. Critics argued, as I did before this Committee, that there would have to be a dramatic reduction in the forecast of future warming in order to reconcile fact and hypothesis.
By 1995, in its second full Assessment of Climate Change, the IPCC admitted the validity of the critics’ position: “When increases in greenhouse gases only are taken into account … most [climate models] produce a greater mean warming than has been observed to date, unless a lower climate sensitivity [to the greenhouse effect] is used … There is growing evidence that increases in sulfate aerosols are partially counteracting the [warming] due to increases in greenhouse gases.” (2)
I believe the secular translation of this statement is that either it is not going to warm up as much as was previously forecast, or something is hiding the warming. I predict every attempt will be made to demonstrate the later before admitting that former is true.[1]
Such attempts were made, and initial results, particularly those published in Nature on July 4, 1996 (3), appeared to bolster the argument that the sulfates were masking the expected warming. That particular study used annual weather balloon data from 1963 through 1987. Most striking was a rapid warming of the middle of the Southern Hemisphere, where there in fact are virtually no sulfates available to counter greenhouse warming.
[1] However, one of the United Kingdom’s most prominent modelers, who surely does not want his name revealed, informed me in Asheville, North Carolina on June 5, 1997 that “it appears we have over‐estimated the sensitivity of the climate to greenhouse changes.”
However, when the entire record of weather balloon data, from 1958 through 1995, was used, this most pronounced region of warming turned out to show no change whatsoever (4) (Figure 2).[OMITTED] In response to this, the senior author of the original study told the December meeting of the American Geophysical Union that the correspondence between the sulfate/greenhouse model and reality vanished because greenhouse warming had overwhelmed sulfate cooling since 1987. As there was no net change in any of the temperature records in the last decade (Figure 1), this statement was clearly wrong. In an on‐line discussion recently published, the explanation is now given that sulfate cooling “leaked” into the Southern Hemisphere, or exactly the opposite of the explanation given a mere four months earlier.
Temperature Trend from 1963–1987
[OMITTED]
Clearly the default option‐that it’s simply not going to warm as much as the earlier projections had indicated‐is increasingly attractive. And a new suite of climate models, which now seem to fit the observed history more accurately, bear witness to this conclusion.
Figure 3[OMITTED] shows the new result from the United Kingdom Meteorological Office model (5). The published forecast is the higher value, which still shows considerable warming. But a careful read of the related manuscript reveals that the changes in the greenhouse effect that were used are much greater than the observed and projected changes. When the more accepted values (as given by the IPCC) are used, the warming drops to the lower figure, or about 17* by the year 2100.
Figure 4 is an analogous new model from the U.S. National Center for Atmospheric Research, as published in the May 16 issue of Science (6). It, too, uses a change in the greenhouse effect at least 30% greater than the known and projected changes. The lower figure adjusts this model for that error and it produces only 1.3* of warming by 2100.
Notably this model does not include any cooling from sulfates. VAlile this effect was apparently overestimated, new, direct measurements by Hobbs et al., indicate that it should reduce warming by about 1.3* over this period (7).
The Nature of Observed Change
Greenhouse physics predicts that the driest air masses should respond first and most strongly to changes induced by human activities. These, in fact, are generally the coldest air masses such as the great high pressure system that dominates Siberia in the winter, and its only slightly more benign cousin in northwestern North America. When the jet stream attains a proper orientation, it is this air mass that migrates south and kills orange trees in Florida.
A look at the trends in the satellite data — our only truly global record of lower atmosphere temperature‐is remarkably revealing (Figure 5).[OMITTED] In spite of a statistically significant global cooling trend over the 18.5 year period of record, there is a pronounced warming trend in the coldest winter regions (Figure 6).[OMITTED]
Another way to appreciate observed change in a frame of reference longer than the satellite record is to look at the ground‐based thermometers for the last fifty years. In Figure 7,[OMITTED] I have subtracted the summer temperature changes from the winter ones. The redder the map, the more pronounced is the warming in the winter versus the summer.
Much has been made in recent years of an apparent increase in what has been called “extreme” rainfall. Federal climatologists recently produced a press release, during last winter’s floods in California, claiming that these rains had increased by 20%. This was a gross distortion of reality.
Global Satellite‐measured Temperature Departures
[OMITTED]
The original study, by Thomas Karl and others (8), showed that the percent of rain in the United States that falls from storms of two inches or more in 24 hours has increased from 9% of all rain to 11%. This is a change of 2%. However, in order to create a sensational effect, this 2% change was divided by the average amount of 10%, resulting in a figure of 20%! In reality, what Karl found was that, on the average, there is one more day in every 730 in which the two‐inch threshold is exceeded. Karl also informed me that there is no significant change in rain of three inches per day or more. Is a two‐to‐three inch rainfall “extreme”? Or, given the fact that much of our agricultural region is in moisture deficit every summer, is it “beneficial”? Simple logic can make that value judgement.
Imagine if the truth had been told: The percent of rainfall originating from storms of less than two inches per 24 hours has declined from 91% of all rain to 89%. Unfortunately, there is no news and no scare value in the truth.
Another View of the Future
I believe that it is fair to say that the people once labeled as “a small band of skeptics” — those who championed the position that warming would be modest and primarily in the coldest air‐masses have won the day.
Many of these same scientists are now forming a new environmental paradigm. It is that the concept of “fragile earth” must be abandoned. And it asks the impertinent question: since when is everything that man does to the planet necessarily bad?
During the 20th century, we have already proceeded more than half way to radiatively doubling the natural carbon dioxide greenhouse effect. Here is what resulted:
Life expectancy doubled in the free and developed world. The developing world is catching up as their emissions rise. Corn production per acre increased five‐fold. The growing season in the coldest latitudes increased slightly, but enough to increase greenness by 10% (8). Rainfall in the world’s breadbaskets increased slightly, even as summer temperatures did not warm. Australia reports a massive increase in agricultural production that may be related to climate (9).
There are thousands of laboratory and field experiments, as well as the practical activities of professional horticulturalists, that demonstrate that rising carbon dioxide makes most plants grow better. Consider the writing of Sylvan Wittwer, the man who conducted some of the very first experiments on this phenomenon. He ultimately became chairman of the Board on Agriculture of the National Research Council.
There is currently a blind spot in the political and informational systems of the world. This is accompanied by a corruption of the underlying biological and physical sciences. It should be considered good fortune that we are living in a world of gradually increasing levels of atmospheric CO2 .… The rising level of atmospheric CO2 does not make the United States the world’s worst polluter. It is the world’s greatest benefactor. Unlike other natural resources (land, water, energy) essential for food production, which are costly and progressively in shorter supply, the rising level of atmospheric CO2 is a universally free premium on which we can all reckon for the future.[2]
I must ask this Committee the real questions of the day: How much of the money of the citizens of this nation are you willing to spend to stop this? How much to stop a slight amelioration of the coldest temperatures, in the air‐masses most inhospitable to unprotected life where there is human settlement? How much to stop making the earth greener, more productive, and human life increasingly long over the mass of the planet that still finds us the envy of history?
[2] Members of the Senate would do well to read Wittwer’s book, Food, Climate and Carbon Dioxide (10) a distillation of his 750 articles in the refereed scientific literature.
* Degrees, centigrade
References
(1) Houghton, J.T., G.J. Jenkins, and J.J. Ephraums (Eds.) (1990). Climate Change: The IPCC Scientific Assessment. Cambridge: Cambridge University Press.
(2) Houghton, J.T., L.G. Meira Filho, B.A. Callander, N. Harris, A. Kattenberg, and K. Maskell (Eds.) (1996). Climate Change 1995: The Science of Climate Change. Cambridge: Cambridge University Press.
(3) Santer, B.D., et al. (1996). A Search for Human Influences on theThermal Structure of the Atmosphere. Nature, 382,39–45.
(4) Michaels, P.J. and P.C. Knappenberger, 1996. Human Effect on Global Climate? Nature, 384, 522–523.
(5) Mitchell, LF.B. and T.C. Johns (1997). On modification of Global Warming by Sulfate Aerosols. Journal of Climate, 10, 245–266.
(6) Kerr, R.A. (I 997). Model Gets It Right‐Without Fudge Factors, Science, 276, 1041.
(7) Hobbs, RV, et al. (1997). Direct Radiative Forcing by Smoke from Biomass Burning, Science, 275, 1777.
(8) Karl, T.R. et al. (1995). Trends in high‐frequency climate variability in the 20th century. — Nature, 337, 217–220.
(9) Myneni, et al. (1997). Increased plant growth in the northern high latitudes from 1981 to 1991. Nature, 386, 698–702.
(10) Nicholls, N. (1997) Increased Australian wheat yield due to recent climate trends. Nature, 387, 484–485.
(11) Wittwer, S.H. (1995). Food, Climate and Carbon Dioxide. CRC Press, Boca Raton, Fla. 236pp. CATOCLIPS — Congressional Testimony by Federal… (CGT)