Nearly ten years ago, I testified before the Senate ForeignRelations Committee. At that time, I argued that forecasts ofdramatic and deleterious global warming were likely to be in errorbecause of the very modest climate changes that had been observedto that date. Further, it would eventually be recognized that thismore moderate climate change would be inordinately directed intothe winter and night, rather than the summer, and that this couldbe benign or even beneficial. I testified that the likely warming,based on the observed data, was between 1.0 and 1.5* fordoubling the natural carbon dioxide greenhouse effect.
Since then, the global mean temperature of the earth has notwarmed a bit. Three independent measuring systems (and the onlythree that exist) -- surface measured temperature, temperatures ofthe lower atmosphere measured by weather balloons, and temperatureof the lower atmosphere measured by orbiting satellites-all show nowarming since that testimony (see Figure 1).[OMITTED]
Global Temperature Departures
In science, regardless of how much external political and socialpressure is applied, it is inevitable that observed data andtheoretical hypotheses will eventually reach an internallyconsistent equilibrium. However, it was apparent that when thefirst "consensus" was imposed on the issue of global warming, bythe First Scientific Assessment of the United NationsInter-governmental Panel on Climate Change (1990), that such anequilibrium had not been reached.
That report stated that "when the latest atmospheric models arerun with the present concentrations of greenhouse gases, theirsimulation of climate is generally realistic on large scales." (1)The suite of climate models extant at the time predicted that theglobe's mean temperature should have risen by 1.3* to2.3*, with the larger figure for the NorthernHemisphere, where most of us live. These models provided thetechnical background for the Framework Convention on ClimateChange, signed in 1992.
The observed warming since the late 19th century was0.5*, or less than one-third of the predicted value.Critics argued, as I did before this Committee, that there wouldhave to be a dramatic reduction in the forecast of future warmingin order to reconcile fact and hypothesis.
By 1995, in its second full Assessment of Climate Change, theIPCC admitted the validity of the critics' position: "Whenincreases in greenhouse gases only are taken into account ... most[climate models] produce a greater mean warming than has beenobserved to date, unless a lower climate sensitivity [to thegreenhouse effect] is used ... There is growing evidence thatincreases in sulfate aerosols are partially counteracting the[warming] due to increases in greenhouse gases." (2)
I believe the secular translation of this statement is thateither it is not going to warm up as much as was previouslyforecast, or something is hiding the warming. I predict everyattempt will be made to demonstrate the later before admitting thatformer is true.
Such attempts were made, and initial results, particularly thosepublished in Nature on July 4, 1996 (3), appeared to bolster theargument that the sulfates were masking the expected warming. Thatparticular study used annual weather balloon data from 1963 through1987. Most striking was a rapid warming of the middle of theSouthern Hemisphere, where there in fact are virtually no sulfatesavailable to counter greenhouse warming.
 However, one of the United Kingdom's most prominentmodelers, who surely does not want his name revealed, informed mein Asheville, North Carolina on June 5, 1997 that "it appears wehave over-estimated the sensitivity of the climate to greenhousechanges."
However, when the entire record of weather balloon data, from1958 through 1995, was used, this most pronounced region of warmingturned out to show no change whatsoever (4) (Figure 2).[OMITTED] Inresponse to this, the senior author of the original study told theDecember meeting of the American Geophysical Union that thecorrespondence between the sulfate/greenhouse model and realityvanished because greenhouse warming had overwhelmed sulfate coolingsince 1987. As there was no net change in any of the temperaturerecords in the last decade (Figure 1), this statement was clearlywrong. In an on-line discussion recently published, the explanationis now given that sulfate cooling "leaked" into the SouthernHemisphere, or exactly the opposite of the explanation given a merefour months earlier.
Temperature Trend from 1963-1987
Clearly the default option-that it's simply not going to warm asmuch as the earlier projections had indicated-is increasinglyattractive. And a new suite of climate models, which now seem tofit the observed history more accurately, bear witness to thisconclusion.
Figure 3[OMITTED] shows the new result from the United KingdomMeteorological Office model (5). The published forecast is thehigher value, which still shows considerable warming. But a carefulread of the related manuscript reveals that the changes in thegreenhouse effect that were used are much greater than the observedand projected changes. When the more accepted values (as given bythe IPCC) are used, the warming drops to the lower figure, or about17* by the year 2100.
Figure 4 is an analogous new model from the U.S. National Centerfor Atmospheric Research, as published in the May 16 issue ofScience (6). It, too, uses a change in the greenhouse effect atleast 30% greater than the known and projected changes. The lowerfigure adjusts this model for that error and it produces only1.3* of warming by 2100.
Notably this model does not include any cooling from sulfates.VAlile this effect was apparently overestimated, new, directmeasurements by Hobbs et al., indicate that it should reducewarming by about 1.3* over this period (7).
The Nature of Observed Change
Greenhouse physics predicts that the driest air masses shouldrespond first and most strongly to changes induced by humanactivities. These, in fact, are generally the coldest air massessuch as the great high pressure system that dominates Siberia inthe winter, and its only slightly more benign cousin innorthwestern North America. When the jet stream attains a properorientation, it is this air mass that migrates south and killsorange trees in Florida.
A look at the trends in the satellite data -- our only trulyglobal record of lower atmosphere temperature-is remarkablyrevealing (Figure 5).[OMITTED] In spite of a statisticallysignificant global cooling trend over the 18.5 year period ofrecord, there is a pronounced warming trend in the coldest winterregions (Figure 6).[OMITTED]
Another way to appreciate observed change in a frame ofreference longer than the satellite record is to look at theground-based thermometers for the last fifty years. In Figure7,[OMITTED] I have subtracted the summer temperature changes fromthe winter ones. The redder the map, the more pronounced is thewarming in the winter versus the summer.
Much has been made in recent years of an apparent increase inwhat has been called "extreme" rainfall. Federal climatologistsrecently produced a press release, during last winter's floods inCalifornia, claiming that these rains had increased by 20%. Thiswas a gross distortion of reality.
Global Satellite-measured TemperatureDepartures
The original study, by Thomas Karl and others (8), showed thatthe percent of rain in the United States that falls from storms oftwo inches or more in 24 hours has increased from 9% of all rain to11%. This is a change of 2%. However, in order to create asensational effect, this 2% change was divided by the averageamount of 10%, resulting in a figure of 20%! In reality, what Karlfound was that, on the average, there is one more day in every 730in which the two-inch threshold is exceeded. Karl also informed methat there is no significant change in rain of three inches per dayor more. Is a two-to-three inch rainfall "extreme"? Or, given thefact that much of our agricultural region is in moisture deficitevery summer, is it "beneficial"? Simple logic can make that valuejudgement.
Imagine if the truth had been told: The percent of rainfalloriginating from storms of less than two inches per 24 hours hasdeclined from 91% of all rain to 89%. Unfortunately, there is nonews 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 positionthat warming would be modest and primarily in the coldestair-masses have won the day.
Many of these same scientists are now forming a newenvironmental paradigm. It is that the concept of "fragile earth"must be abandoned. And it asks the impertinent question: since whenis everything that man does to the planet necessarily bad?
During the 20th century, we have already proceeded more thanhalf way to radiatively doubling the natural carbon dioxidegreenhouse effect. Here is what resulted:
Life expectancy doubled in the free and developed world. Thedeveloping world is catching up as their emissions rise. Cornproduction per acre increased five-fold. The growing season in thecoldest latitudes increased slightly, but enough to increasegreenness by 10% (8). Rainfall in the world's breadbasketsincreased slightly, even as summer temperatures did not warm.Australia reports a massive increase in agricultural productionthat may be related to climate (9).
There are thousands of laboratory and field experiments, as wellas the practical activities of professional horticulturalists, thatdemonstrate that rising carbon dioxide makes most plants growbetter. Consider the writing of Sylvan Wittwer, the man whoconducted some of the very first experiments on this phenomenon. Heultimately became chairman of the Board on Agriculture of theNational Research Council.
There is currently a blind spot in the political andinformational systems of the world. This is accompanied by acorruption of the underlying biological and physical sciences. Itshould be considered good fortune that we are living in a world ofgradually increasing levels of atmospheric CO2 .... The risinglevel of atmospheric CO2 does not make the United States theworld's worst polluter. It is the world's greatest benefactor.Unlike other natural resources (land, water, energy) essential forfood production, which are costly and progressively in shortersupply, the rising level of atmospheric CO2 is a universally freepremium on which we can all reckon for the future.
I must ask this Committee the real questions of the day: Howmuch of the money of the citizens of this nation are you willing tospend to stop this? How much to stop a slight amelioration of thecoldest temperatures, in the air-masses most inhospitable tounprotected life where there is human settlement? How much to stopmaking the earth greener, more productive, and human lifeincreasingly long over the mass of the planet that still finds usthe envy of history?
 Members of the Senate would do well to read Wittwer's book,Food, Climate and Carbon Dioxide (10) a distillation of his 750articles in the refereed scientific literature.
* Degrees, centigrade
(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 UniversityPress.
(3) Santer, B.D., et al. (1996). A Search for Human Influenceson theThermal Structure of the Atmosphere. Nature, 382,39-45.
(4) Michaels, P.J. and P.C. Knappenberger, 1996. Human Effect onGlobal Climate? Nature, 384, 522-523.
(5) Mitchell, LF.B. and T.C. Johns (1997). On modification ofGlobal Warming by Sulfate Aerosols. Journal of Climate, 10,245-266.
(6) Kerr, R.A. (I 997). Model Gets It Right-Without FudgeFactors, Science, 276, 1041.
(7) Hobbs, RV, et al. (1997). Direct Radiative Forcing by Smokefrom Biomass Burning, Science, 275, 1777.
(8) Karl, T.R. et al. (1995). Trends in high-frequency climatevariability in the 20th century. - Nature, 337, 217-220.
(9) Myneni, et al. (1997). Increased plant growth in thenorthern high latitudes from 1981 to 1991. Nature, 386,698-702.
(10) Nicholls, N. (1997) Increased Australian wheat yield due torecent climate trends. Nature, 387, 484-485.
(11) Wittwer, S.H. (1995). Food, Climate and Carbon Dioxide. CRCPress, Boca Raton, Fla. 236pp. CATOCLIPS - Congressional Testimonyby Federal... (CGT)