"Greenhouse Effect Said To Be Proved" is the title Associated Press writer Alex Dominguez gave to his report of the Harries et al. paper; while environmental correspondent Natalie Pawelski introduced her story of the group's research with the words "Satellite Data Proves Greenhouse Effect."  Scientists such as Drew Shindell of NASA's Goddard Institute for Space Studies were reported to be saying much the same thing, as were some of the scientists who produced the provocative report.  Harries himself, for example, was quoted as stating that the work of his team showed "the greenhouse effect is operating and what we are seeing can only be due to the increases in the gases" responsible for it.  Unnamed atmospheric scientists not involved in the study were also reported to have said "the satellite data provide concrete confirmation that greenhouse gases are building up."  And Shindell was reported to have said the new research "should end the debate over the greenhouse effect."

Likely lost on the majority of the public in this flurry of news reports was the fact that there is no debate over the greenhouse effect.  All atmospheric scientists agree, for example, that CO2 is indeed a "greenhouse gas."  Neither does anyone dispute the claim that increases in its atmospheric concentration will produce a tendency for temperatures to rise.  No, it's what happens after an intensification of the greenhouse effect that is the cause of contention, i.e., how earth's complex climate system responds to this impetus for warming.  In effect, therefore, the study of Harries et al. does no more than confirm the fact that, as the unnamed scientists put it, "greenhouse gases are building up," which is something we have long known from direct measurements of their atmospheric concentrations, as well as from analogous measurements made on air bubbles trapped in polar and glacial ice.  Yet in an article entitled "Getting Real," The Economist says the Harries et al. paper "is something worth pondering in a week when George Bush, America's president, announced that he had no intention of honoring his campaign pledge to regulate emissions of carbon dioxide," as if to suggest that some incredible new knowledge had suddenly become available to mankind.  Perhaps the article's author should rather ponder his navel; it would yield as much useful information.

Also likely lost on the majority of the public were the much-less-hyped findings of Lindzen et al. (2001), whose seminal paper is also described in the Journal Reviews section of this week's issue of our magazine.  These scientists analyzed cloud cover and sea surface temperature (SST) data over a large portion of the Pacific Ocean, finding a strong inverse relationship between upper-level cloud area and mean SST, indicative of a phenomenon that operates in such a manner as to "resist changes in tropical surface temperature."  Furthermore, they determined that this negative climate change feedback may be strong enough to "more than cancel all the positive feedbacks" included in today's most advanced climate models.  And they demonstrated that this potential real-world impediment to global warming did not appear to function in these models.

Most scientists who keep abreast of ongoing developments in the field of climate change research recognize the great significance of the Lindzen et al. findings.  In fact, even the British group that documented the intensification of the clear-sky greenhouse effect over the past three decades has admitted that whether this finding "will lead to global warming or global cooling is unclear," according to Pawelski, who also quotes Harries as saying "the effect of clouds on the planet is very complex, and frankly we don't understand it."

So why do we title our editorial A Tale of Two Atmospheres?  We do so to highlight the great difference between what is predicted to happen to a pristine cloud-free atmosphere and one that includes the real-world complexities introduced by but one other factor, the presence of clouds, when there is an intensification of the cloudless atmosphere's greenhouse effect.  This is the lesson that is well worth pondering.  And if one is honest with oneself, it casts "America's president," as The Economist refers to Mr. Bush, in a much more favorable light than the climate alarmists who are gnashing their teeth over his reasoned response to realities they refuse to recognize.