Paul Craig Roberts, in his column "What's flying out the ozone hole? Billions of dollars" (Economic Viewpoint, June 13), makes several misleading assertions regarding the transition away from ozone-depleting substances. By exaggerating the costs and misstating scientific understanding, he creates the very hysteria he accuses others of
For example, Roberts claims that minor repairs to car air conditioners "can now cost as much as $1,000." In fact, the initial retrofit kits that several auto makers developed cost $100 to $150. Cars bought recently and in the future will not need any retrofit, since they already contain HFC-134a. Car owners should note that they are not required to stop using the original refrigerant.
Roberts quotes scientists as saying that there has been no evidence of ozone depletion or increases in ultraviolet light (UV) outside seasonal effects over Antarctica. This contrasts with the latest assessment by the world's most distinguished atmospheric researchers, which states that in addition to winter depletion, "for the first time, there is evidence of significant decreases [in ozone] in spring and summer in both the Northern and Southern hemispheres." The assessment took into account natural variations in ozone concentration, including volcanic eruptions, seasonal changes, sunspots, and latitudinal effects, and depletion is still evident. The world's nations would not have agreed to such a rapid phaseout of ozone-depleting compounds without such strong evidence.
U.S. Environmental Protection Agency
Paul Craig Roberts misrepresents the 1992 findings issued by NASA and NOAA. Scientists disclosed record-high levels of chlorine monoxide in the stratosphere over North America. Given the proper meteorology, the northern atmo-sphere was primed for record ozone depletion. (A warmer-than-normal winter held ozone depletion in the Northern Hemisphere to levels consistent with previous years. The winter of 1993 saw the same chemistry and worse ozone depletion as the upper atmosphere stayed colder longer.) At no time was an ozone hole predicted. The connection between CFCs and ozone depletion is clear.
Charles F. Kennel
for Mission to Planet Earth