MEDICAL METAPHORS FOR CLIMATE ISSUES∗An Editorial EssayRICHARD C. J. SOMERVILLEScripps Institution of Oceanography, University of California, San Diego, La Jolla,CA 92093-0224, USAE-mail: [email protected] climate scientists are planetary physicians. We have learned many things aboutclimate, but we still have a lot to learn. Like the findings of medical science, ourunderstanding of climate, although incomplete, is already highly useful.For example, the fundamental question of whether all of us, more than 6 billionhumans, by adding to the greenhouse effect, have caused the world to warm up inrecent decades, has already been answered. The answer is yes. We’ve settled thatissue. At least, we climate scientists consider it settled. Some people may choosenot to believe it. There are people who are unwilling to believe things that they wishwere not true, or who simply don’t trust experts.The public has come to respect medical science, however, and, although therewill always be gullible people, most of us know there’s a difference between realexperts and charlatans. Most people won’t listen to, or act on, medical advice froma quack who can talk plausibly about medicine but who isn’t really a physician.Everybody accepts this situation. Even the least enlightened members of the U.S.Congress don’t hold hearings to denounce modern medical science as a hoax. Yet,a few politicians and hard-core skeptics do attack climate science in exactly thisway.Medicine is different. At your annual checkup, if you’re sensible, when thedoctor tells you to lose weight and exercise more, you don’t argue. You don’t insultyour doctor by complaining that medical science is imperfect and can’t yet preventcancer or cure AIDS. You don’t label your doctor a radical alarmist. You know, andyour doctor knows, that medical science, while inevitably incomplete, is still goodenough to provide advice well worth following.Of course, some people just will not do what experts tell them. Non-complianceby some patients is a big problem for physicians. We should keep all this in perspec-tive. Lest we fall into the trap of thinking that medical science is a perfect role modelfor us climate scientists who crave public esteem, it is also good to remember that ittook a long time for many medical results to acquire widespread acceptance. Some∗This essay is based on a talk given October 8, 2005 at the Yale Conference on Climate Change:From Science to Action, held in Aspen, Colorado, USA.Climatic Change (2006)DOI: 10.1007/s10584-006-9084-8c Springer 2006RICHARD C. J. SOMERVILLEscientists in the 1930 s already suspected that tobacco caused cancer. The evidencewas widely known to be strong by the 1960 s. Yet the high-profile anti-tobaccolawsuits began in the United States only in the 1990 s. Globally, there has been areduction in tobacco use in numerous countries. Throughout the world, however,many people still smoke.The big problem in human-caused climate change is carbon dioxide emittedinto the atmosphere by human activity. We produce most of it when we burn oiland coal and natural gas to generate energy. It adds to the greenhouse effect andcauses climate change. A few far-seeing scientists realized this clearly more thana century ago. Yet accurate measurements of carbon dioxide in the atmospherebegan only in the late 1950 s. We have known for only about half a century thatatmospheric carbon dioxide is increasing. We ought to remember this half-centurytime scale when we get impatient about the slow pace of progress in action againsthuman-caused climate change.Incidentally, like many climate scientists, I have an aversion to the catchy term“global warming” although I realize it’s in the language to stay. It’s an over-simplification. Climate is far more than just temperature. Climate is a rich tapestryof interlinked phenomena, multi-faceted and inherently complex. The most impor-tant aspects of climate change are local, not global, and are not confined to warming.Global warming is just a symptom of planetary ill health, like a fever.You and your physician both know that fever is important but is not the wholestory. At your annual checkup, you don’t confine yourself to body temperaturewhen discussing your health. Even the most ignorant patient realizes that measuringtemperature alone cannot enable the physician to diagnose an illness and prescribetreatment.Instead, everybody knows that a body temperature only a few degrees abovenormal is a symptom that can indicate medical problems that may have seriousconsequences, sometimes including death. Yet we still haven’t educated most peo-ple to understand that a planetary fever of a few degrees can mean melting ice caps,rising sea level, massive disruptions in water supply, killer heat waves, and strongerhurricanes.Many intelligent people still laugh at the small numbers we use in describingclimate change. They think a global warming of a few degrees is trivial. They maysay that moving from one city to another often involves a much greater warming,yet may actually be quite pleasant. These people don’t grasp the important dif-ference between local changes and global ones. They don’t realize that when thesurface atmospheric temperature of the entire planet changes by a few degrees, theimplications are enormous. Entering an ice age, to cite one example, involves aglobal cooling of only a few degrees.Many people also mistakenly believe that a rapidly warming climate is justa minor inconvenience that can be handled by air conditioning and other simpletechnological fixes. This massive degree of misunderstanding may be due in partto a failure to educate people about science. It may also be the case that peopleMEDICAL METAPHORS FOR CLIMATE ISSUEShave become confused by the widespread misperception that the science of climatechange is immature, uncertain, characterized by raging controversy and not to betrusted. An effective campaign of deliberate disinformation about climate sciencehas helped spread this false impression.Medical science has achieved a measure of widespread respect that climatescience can only envy. Journalists covering a medical discovery aren’t usuallysuspicious of researchers and don’t inevitably insist on hearing from “the opposingview.” When reporting on research showing the need for people to eat sensibly andbe physically active, the media do not frame the story of these scientific advancesin terms of a debate or dispute.