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and pains would be overdiagnosed.Ó to 2.3 percent above the 1990 level, to Some preexisting categories were re- 1,369 million metric tons.
tested but none removed. In the past, The governmentÕs own carbon emis- 2 emissions may put gay activists lobbied to have homosex- reduction goal beyond reach sion numbers will be published later uality erased from the DSM register; this year, but oÛcials say they are un- feminists likewise had PMS banished to likely to diÝer signiÞcantly from Geller the appendix, awaiting further research.
and LaitnerÕs Þgures. Geller and Laitner ÒMost diagnostic categories donÕt have On April 21, 1993ÑEarth DayÑ President Bill Clinton announced used the Department of EnergyÕs most opponents who demand that the APA that the U.S. would reduce its recent estimates of 1993 fuel consump- scrutinize the evidence,Ó Kirk says. ÒThe emissions of greenhouse gases to their tion. The calculation methods are stan- arbitrary line of what gets included is 1990 levels by the year 2000. The pledge dard. In other words, emissions have drawn with some political sensitivity.Ó was intended to show that the U.S. took increased enough in three years to take Still, the DSMÕs contents must corre- seriously the Framework Convention on up three quarters of the allotment for spond to those found in the Interna- Climate Change that had been agreed the whole decade. The U.S.Õs commit- tional ClassiÞcation of Diseases (ICD), on at the Earth Summit in Rio de Janeiro ment to return to the levels of 1990 published by the World Health Organi- in 1992. Other industrialized countries by 2000 appears out of reach, unless zation. By treaty, the U.S. must base made the same promise. The adminis- strong new steps are taken to curb fur- surveys of mental health on ICD stan- tration followed through in October of ther growth in emissions.
dards. In some cases, more than one last year by publishing its Òclimate Geller says the upturn in 1993 results DSM-IV disorder falls under the same change action plan,Ó which speciÞed largely from a 4.9 percent gain in eco- ICD-IX heading. And the ICD-IX num- how the target would be met.
nomic activity since 1990. He and his bers are diÝerent from those used in Less than a year later the action plan colleagues as well as workers at the Nat- the ICD-X, which debuted last year. A isÑif not quite in tattersÑunder severe ural Resources Defense Council have DSM appendix explains how to cross- strain. The document allows for an in- proposed several eÛciency initiatives reference ICD-IX and ICD-X codes.
crease of 3 percent in U.S. carbon diox- that they say could bring the target back So why does DSM-IV use codes from ide output by 2000 because emissions in reach. The proposals include further an earlier version of ICD? ÒIt may take of other greenhouse gases are expected improvements in automobile fuel eÛ- another seven years before ICD-X stan- to fall, leaving a level total. But calcu- ciency and laws to require the use of dards are adopted in this country,Ó lations completed in July by Howard recycled material in aluminum and plas- Frances explains. By then, Kutchins ven- Geller and Skip Laitner of the American tic production. GellerÕs group would tures a guess that a new DSM, sure to Council for an Energy-EÛcient Econo- also like states to reform the regulation be a publishing success, may be on the my indicate that carbon emissions in of utilities so that investments in ener- the U.S. had by last year already climbed gy eÛciency will become at least as SCIENTIFIC AMERICAN September 1994 Copyright 1994 Scientific American, Inc.

U.S. EMISSIONS of carbon dioxide seem to be headed higher than those calledfor in the climate change action planand higher than the baseline projection,which assumed no special controls. profitable as those in energy supply.
If the U.S. fails to honor its commit- ment, which is not legally binding, itwill be unable to say that it was notwarned. The World Energy Council, anindustry organization, stated in a report called Energy for TomorrowÕs World,which was published last year, that ACTUAL EMISSIONS there was Òno realistic possibilityÓ thatunder current policies developed coun- CLIMATE CHANGE ACTION CARBON (MILLIONS OF METRIC TONS) tries could meet the goal of returningto 1990 emission levels by the year BASELINE PROJECTION 2000 [see ÒTurning Green,Ó page 96].
Looking at the world as a whole, esti- 1985 1990 1995 2000 mated carbon dioxide emissions fromfossil fuels have decreased slightly since1991, according to estimates by the the slight fall in carbon dioxide emis- South Pole and on Mauna Loa in Ha- Worldwatch Institute in Washington, sions resulting from human economic waii. They think natural processes, in- D.C. But analysts agree that the expla- activity and a slowdown in the rate of cluding the eruption of Mount Pinatu- nation for the fall lies in the recession accumulation of atmospheric carbon bo in the Philippines in 1991, are large- and, especially, the economic chaos in dioxide from all sources between 1991 ly responsible for the slower buildup of Russia and eastern Europe. The 1991 and 1993. But the link is tenuous, say the gas between 1991 and 1993.
oil Þres in Kuwait may also have con- Charles D. Keeling and Timothy Whorf An ÒEl Ni–o,Ó a periodic global climat- tributed. So the downswing is unlikely of the Scripps Institution of Oceanogra- ic disturbance, persisted during those to be permanent.
phy in La Jolla, Calif., who monitor car- years, and that anomaly may temporar- It is tempting to see a link between bon dioxide levels at stations at the ily increase the oceanÕs uptake of car- Copyright 1994 Scientific American, Inc.
SCIENTIFIC AMERICAN September 1994 19

bon dioxide. Pinatubo threw dust into Concern emerged two years ago when the stratosphere that caused cooling a group of Canadian scientists report- below and, possibly, increased precipi- ed that rodents that were given Prozac tation. Keeling and Whorf speculate that and Elavil experienced an increase in those eÝects spur plants to take more the rate of growth of breast cancers and carbon dioxide out of the atmosphere.
increases in the weight of other tumors.
In any event, the go-slow was only Recent work with antihistamines deep- temporary: this year the rate of carbon ens the concern. The research team, led dioxide buildup measured at Mauna Loa by Lorne J. Brandes, an oncologist at the picked up again and is at the high end University of Manitoba, has revealed a of predictions based on known human possible mechanism by which antihis- emissions. The great experimentÑhow tamines and antidepressants may en- life will change in a highÐcarbon dioxide courage tumor growth.
atmosphereÑseems to be getting un- Antidepressants and antihistamines ÑTim Beardsley are closely related in function. Both block chemical messengers that are re- leased by white blood cells known as mast cells. Antihistamines counteracthistamine, which triggers allergic re- LIFE IN THE UNIVERSE Could Prozac and Elavil sponses. Antidepressants generally promote tumor growth? function by blocking the reuptake ofserotonin, a neurotransmitter that is important in the regulation of emotions.
IN THE UNIVERSE
Steven Weinberg Some oncologists have begun to Because the chemical structure of sero- contemplate the disturbing pros- tonin is similar to that of histamine, pect that two of their favorite antidepressants can also interfere with agents, Prozac and Elavil, might be med- histamine by binding to its receptor ical boomerangs. Episodes of severe depression occur three times more fre- Brandes and his colleagues have dis- OF THE EARTH
quently in cancer patients than in the covered a new receptor site in the fam- general population, and women are vic- ily of enzymes known as cytochrome- Robert P. Kirshner tims of depression more often than P450. Cytochrome-P450 is involved in men. Prozac and Elavil can alleviate the regulating cell metabolism, detoxiÞca- depression that often accompanies tion of the intracellular environment breast cancer and other malignancies.
and cell growth. Brandes believes that Now there is disturbing evidence that both the antidepressants and antihis- the popular antidepressants may accel- tamines bind to the cytochrome-P450 erate tumor growth.
receptor sites. The result, he suspects, Stephen Jay Gould William H. Calvin Robert W. Kates WILL ROBOTS
INHERIT THE EARTH?
Marvin Minsky THE SEARCH FOR
Carl Sagan SEPTEMBER 27
LORNE J. BRANDES studied the progression of cancer in rodents that received an-tidepressant or antihistamine drugs in doses equivalent to those for humans. Heobserved accelerated tumor growth. SCIENTIFIC AMERICAN September 1994 Copyright 1994 Scientific American, Inc.

Source: http://academic.evergreen.edu/z/zita/articles/SciAm/GW_CC/TooMuchUSco2_1994.pdf