Analog SFF, April 2010

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Reader's Department: EDITORIAL: THE REST OF THE DATA by Stanley Schmidt

Department: BIOLOG: BRENDA COOPER by Richard A. Lovett

Novelette: SWORDS AND SADDLES by John G. Hemry

Science Fact: WHAT'S IN A KISS?: THE WILD, WONDERFUL WORLD OF PHILEMATOLOG by Richard A. Lovett

Reader's Department: IN TIMES TO COME

Novelette: SNOWFLAKE KISSES by Holly Hight & Richard A. Lovett

Novelette: A SOUND BASIS FOR MISUNDERSTANDING by Carl Frederick

Reader's Department: THE ALTERNATE VIEW: TAKEN ON FAITH by Jeffery D. Kooistra

Novelette: NOTHIN’ BUT BLUE SKIES by Stephen L. Burns

Novelette: WHEN WE WERE FAB by Jerry Oltion

Novelette: THE PLANET HUNTERS by S.L. Nickerson

Novelette: THE ROBOTS’ GIRL by Brenda Cooper

Reader's Department: THE REFERENCE LIBRARY by Don Sakers

Reader's Department: BRASS TACKS

Reader's Department: UPCOMING EVENTS by Anthony Lewis

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Published since 1930

First issue of
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January 1930 (c)

In his November 2009 Alternate View column, “Lessons From the Lab,” my esteemed colleague Jeffery D. Kooistra lucidly pointed out a widespread flaw in some of the data that have been used to argue for the need to do something about global warming. He cited a study by broadcast meteorologist Anthony Watts to determine the reliability of temperature measurements from a network of stations overseen by the National Weather Service. Watts found frequent errors due to such influences as changing the paint used on the thermometers’ housings and locating the thermometers near heat sources such as electronics and air conditioner exhausts. Since most of these errors tended to produce readings that were too high, Jeff wrote, “. . . along with the unreliable data goes much of the case for global warming."

Certainly the errors weaken the case for global warming—but how much? Jeff has long described himself as a global warming skeptic, and up to a point this is an admirable thing. (I haven't ascertained the exact extent and nature of his skepticism, so I apologize in advance if I appear to attribute to him any view he doesn't actually hold.) It's easy for people (on any side of a question) to get swept up in hype and hysteria, so it's always a good idea to cast a critical eye on the data used to support any position.

In the particular case of global warming, there's plenty of room for skepticism about the extent to which it's actually happening, how long-term or short-term it is, how much of it is manmade, and what if anything we can or should do about it. We need to pin these things down as accurately as we can, without undue delay, because there's potentially large-scale and long-term danger in doing either more or less than the facts warrant.

But while there's ample room for skepticism about these details, it's much harder to be skeptical about whether global warming has been occurring, to whatever extent and for whatever reason, over the last few decades. The data he describes, though clearly flawed, may not be as hopeless as he suggests, and in any case only show that the warming, at least at those stations, is less than previously thought—not nonexistent.

And then there are the rest of the data.

First, consider the data he mentions, gathered by a “network of volunteers” in Anthony Watts's Surface Stations project [1]. The initial analysis suggests that many of the stations were reading high, but not enough to change the measured temperature increase to a decrease. And even if most of them are wrong as they stand, it may still be possible to salvage better data from them.

Often, if you can identify a systematic error, you can correct for it. It may be laborious, but it can be done; and sometimes it's worth doing, especially if the measurements you've taken don't lend themselves to repetition (as is often the case in meteorology and astronomy). Earlier in his column, Jeff describes an experience from his own college days in which he collected some flawed data and his professor told him, “You have NO data!” But then he admits parenthetically that “there was a simple, albeit tedious, way to recover my data and so save my experiment."

I remember a similar experience from my own college lab work. The first thing I ever did that attracted especially favorable comment from my first-year physics lab instructor was an appendix to a lab report titled “Special Notes on the Collapse of the Apparatus.” We were to measure the acceleration of gravity by rolling steel balls down an inclined track and plotting data on a graph whose slope would give us a value of
g
. But the slope of the graph depended on not only
g
but also the slope of our incline, so when the whole thing collapsed with a clatter halfway through the experiment, my partner and I first thought the whole experiment was ruined and we would have to start over. Then we realized that we could keep the data we already had, set the track up as close as we could make it to its original configuration, and continue taking the measurements we hadn't done yet. We wound up with a line with a break in it, where the slope changed abruptly from one value to a slightly different one, instead of a straight line with a single well-defined slope. But by comparing the slopes of the two parts, we were able to get
both
a creditable measurement of
g
and a verifiable measure of how our repaired setup differed from the original.

It may be that something like that, or what Jeff did to salvage his experiment, can be done with the flawed temperature measurements from those thermometer stations. It's likely to be a lot of work—there are a lot of stations—but that's better than simply throwing out decades of data that's flawed in a known way that can be corrected for. And computers can make the job a lot easier than it would have been when the measurements were begun.

That possibility at least potentially takes care of the first reason for believing that the measurement errors Watts's group found cast serious doubt on the reality of global warming.

Second, a flaw in one set of data does not invalidate a hypothesis. The important debate here is about the reality and extent of, and appropriate response to, global warming—not the reliability of the readings from one group of thermometers in painted boxes. Even if those data were hopelessly flawed and completely useless (and that doesn't seem to be the case), they are by no means the only things suggesting global warming. There are huge amounts of data from many other sources, and a serious effort to answer the big question has to consider
all
of them. There are, for example, other direct measurements of temperature, in places ranging from the Arctic to many parts of the ocean. There are measurements and photographs of glacial and polar ice melt and sea level changes.

And there are a lot of other observations, not as neatly numerical as physicists tend to like, but quite clear and perhaps even more meaningful as indicators of large-scale change on a time scale of decades. Those come from the broad area of biology, conspicuously including ecology. Many observers, like Dan Smiley (whose work I mentioned in “Research I” in April 2009), have collected data in a wide range of places clearly showing a trend in recent years toward longer growing seasons, earlier blooms, and later fall color changes. In animals, which are inherently more portable than plants, the symptoms are different but the gist is the same. A given species tends to be adapted to a more or less sharply defined range of climatic conditions. If climate changes, the animals move, vacating areas that have become less hospitable to them and spreading into areas that have become more so.

Many of them have been doing just that, and the trend is almost invariably away from the equator and toward the poles, or from warming valleys toward cooler summits. I'm personally familiar with some examples. I vividly remember when the first red-bellied woodpeckers and black vultures, which I'd always thought of as southern species, appeared in the New York area; the woodpecker has now become quite common and the vulture fairly common. An experienced birder who's lived here longer than I have tells me that Carolina wrens got here just a few years before I did, and they're now common, too. If you browse through the range maps in a good field guide to birds, you'll see quite a few notations like “Expanding Northward.” I'm not sure I've seen any going the other way. You can find similar trends among other groups of animals, but they're most obvious among birds because of their extraordinary mobility.

One nonbird that's dramatically feeling the pinch is the pika, a small mammal related to rabbits and limited to a narrow zone of rocky alpine areas. Pikas are especially fussy about temperature, so they're being forced higher and higher as their old haunts grow warmer. That means they have less and less potential habitat, and rangers and naturalists I've talked to in the Rockies are seriously concerned about their prognosis.[2]

A similar concern applies, by the way, to less particular creatures (like us) who have the option of moving farther from the equator. I've heard it argued that a reasonable amount of global warming wouldn't really be that much of a problem for humans, except for the inconvenience of relocating, because if land near the tropics gets too hot, that near the poles will become more welcoming and we can shift our lives and agriculture there. But don't let the distortion of the Mercator projection fool you—the farther from the equator you get, the less real estate there is in any “equal” latitude range such as 5 degrees, as you can easily verify either by calculating or by looking at a globe.

Skepticism—in the sense of questioning everything—is good. But to get its benefits, you have to be open to listening to all the answers, not just the ones that support what you want to believe. And if you find that some of the data being used in an argument are flawed, you must not fall into the trap of thinking that proves or disproves any of the competing hypotheses. You have to look, with a critical eye, at
all
the data.

[FOOTNOTE 1: In keeping with Jeff's insistence that the quality of all data should be scrutinized, I assume measures were taken to evaluate the quality of the volunteers’ observations, though he didn't mention what they were.]