THE conclusions of 11th plenary meetingof the Intergovernmental Panel onClimate Change (ipcc) held at Rome,Italy, in December 1995, continue to bedebated. The most contentious declaration made by the ipcc states that the"Human influence (in bringing aboutglobal climatic changes) is clearly discernible". It is alleged that the ipcc'ssummary report which presents theproceedings of the meet in a mitshell,has selectively highlighted certain issueswhile choosing to ignore others.Concerns over the misleading nature ofinformation provided by the summaryreport are great because it is the mostwidely-read document brought out bythe ipcc's Second Assessment Reportdocuments (Ecoal, April 1996).
A variety of reasons have generatedthis criticism of ipcc's summary report.Most of the ipcc's climate change forecasts are based on computer models(general circulation models), and haveignored the temperature measurementsof the lower troposphere (the lowestregion of the atmosphere extendingfrom between eight and 18 kin), whichhave been made by satellites andradiosondes (weather balloons).
The latter had been presented by theipcc's working group. They indicate aslight overall decline in temperaturesince 1979, the year when constant satellite monitoring was initiated. On theother hand, measurements of globalsurface temperature; indicate a slightwarming over the same period.
Fred Singer, president of the Scienceand Environmental Policy Project,believes that the ipcc's report is deceptive. According to him, the report correctly states that the climate has warmedby 0.3'c to 0.6'c, in the past century.However, it does not mention that therehas been little if no warming in the last50 years - a time when about 80 percent of the greenhouse gases were addedto the atmosphere. In this context hementions that the findings Of NASA'S(National Aeronautics and SpaceAdministration, us) satellites - regarded as true global measurements -show no warming at all; in fact, theyreport a cooling trend. The NASA datahas been overlooked by the ipcc. Singeralso ciriticises the ipcc for failing to mention the discrepancy in results. "Withclimate models lacking validation, whyshould we trust any of the forecastsabout say future warming or rise in sealevels? And why should we be usingthem as a basis to formulate costly policies ?" he questions.
Some scientists do admit that satellite data does not always give an accuratepicture of surface temperature, butwhen'its trends are compared withradiosonde data, the two match ratherwell. Radiosonde measurements overthe polar region, in the past 40 years,indicate no evidence of warming. Singerdraws attention to the fact that thoughthere is a common consensus amongscientists about the rise in surface temperatures, the ipcc is itself sceptical about the legitimacy of surface temperature records. These doubts are listed intheir 1992 report with the reasons forinefficiency (incomplete spatial coverage, changes in schedules, practices andstation location and occurrence ofurbanisation around many stations,among others).
Accu-Weather, a leading commercial weather forecasting firm states thathemispheric satellite data, rather thansurface temperature data, must be takenas a representative of global atmospheric temperature. The former is more uniformly distributed and covers a largersurface. They feel that if there were anysignificant changes taking place on thesurface, they would be manifested in thelower troposphere too and satelliteswould be recording the same. And tillnow, no such trends have been observedin satellite data. Hence, according toAccu-Weather, not much could be happening at the surface level. The ipcc alsofails to mention some of the positiveaspects of global warming. For instance, the number of droughts faced by theAmerican heartland may be rising butconditions are getting more moist.
The summary for policymakers alsosays, "Our ability to quantify humaneffect on climate is currently limited byuncertainties in key factors includinglong-term natural variability and timeevolving patterns of radiative forcing bygreenhouse gases and aerosols". Thispoint is totally overlooked in the nextparagraph which concludes by sayingthat "Taken together, these results pointtowards a detectable human influenceon global climate."
What surprises most scientists isthat despite the existing uncertainties,the ipcc has taken a formal stand to'confirm' the human hand in globalwarming. Robert Balling, director of climatology at the Arizona StateUniversity at Tempe, us, said that policymakers do not have the time to gothrough the entire document and willinstead read the summary report or relyon the media. Therefore, he stresses thepoint that the information supplied tothe media should be correct and complete. News accounts misinterpret reality when they use selective information.They either make exaggerated claims ormiss out the small but important details.Ultimately, what goes beyond doubt isthat we are still in the dark about theuncertainties in climate.