ALL RELATIONSHIPS HAVE ONE OR MORE TRADEOFFS
As with the elk and farmerfish, all relationships have a tradeoff that may be neither readily apparent nor immediately understood. To illustrate, for most of the past 900 years, the buildings in London were clean, many of which had cream-colored limestone façades. But then things began to change as a result of the introduction of coal-burning stoves. That notwithstanding, the rate of change was so slow the cumulative effects were not readily apparent until a threshold of visibility had been crossed and the protracted exposure to the sooty pollution of city air began to turn the buildings dark gray and black. And so it is that smutty buildings dominated the cities of Europe and the United States for most of the nineteenth and twentieth centuries.1 In fact, archival photographs show that the limestone Cathedral of Learning on the University of Pittsburgh campus in Pennsylvania, built during a period of heavy pollution in the 1930s, became soiled while still under construction.2
Reductions in Pittsburgh’s air pollution began in the late 1940s and 1950s.3 Since then, rain has slowly washed the soiled areas of the 42-story Cathedral of Learning, leaving a white, eroded surface. The patterns of whitened areas in archival photographs show the greatest rates of cleansing occurred on the corners of the high elevations on the building, predominantly where the impact of both rain and wind is most intense. It is also clear that the discoloration of buildings is a dynamic process, whereby the deposition of pollution is a relatively consistent process but is simultaneously washed away to varying degrees and patterns over the building’s surface. Moreover, sooty pollutants soiled buildings, such as the Cathedral of Learning, much more rapidly in the past than they are being cleaned by wind and rain in the present.4
In this century, though, the buildings will gradually become more colorful as the city air is cleaned through the promulgation of pollution-control laws and wind-swept rain that will wash away the encrusted soot. The outcome of such cleaning may well be multi-colored buildings as the natural reddish of some limestone is accentuated or a yellowing process that occurs as a result of pollutants that are more organic in constitution. What’s more, the switch from coal to other fuels has cast the Tower of London in hues that are slightly yellow and reddish-brown. As the atmosphere is cleaned and thus dominated more by organic pollutants, a process of yellowing on stone buildings due to the oxidation of organic compounds in the fumes of diesel and gasoline may become of concern.5 The oxidation of this increased organic content from the exhaust of motor vehicles may have overall aesthetic consequences for the management of historic buildings—namely, recognizing a shift away from the simple gypsum crusts of the past to those richer in organic materials and thus warmer tones, particularly browns and yellows.6
And this says nothing about plant life growing on cleansed buildings, a phenomenon made possible because vehicular exhaust emits less of the sulphates that are present in the pollution from coal, pollution that suppress the growth of algae, lichens, and mosses. Consequently, buildings may come to exhibit greens, yellows, and reddish-brown in different places and various patterns because, while lichens and algae prefer humid environs, such as cracks, they can grow on flat surfaces as well.7
The foregoing deals only with the dynamics of Nature in response to soiling such limestone buildings as the Cathedral of Learning by different types of pollution and the long-term cleansing effects of wind and rain. Added to the tradeoffs among these variables is the diversity of preferences espoused in 2003 by employees of the University.
Whereas some university officials were in favor of scrubbing the building with baking soda to remove the black, 70-year-old industrial grim, Cliff Davidson, the environmental engineer from Carnegie Mellon University who studied the building, prefers to let Nature do the work. Although, according to Davidson, the whiter spots have been scrubbed by wind-driven rain over decades, the darker spots in nooks and crannies might well remain for centuries if they could be cleaned at all. In contrast, Doris Dyen, director of cultural conservation for the Rivers of Steel National Heritage Area, expressed appreciation of how buildings in Pittsburgh were being spruced up. “At the same time,” she said, “you can lose a little bit of a sense of what Pittsburgh was like for 100 years when all the buildings were showing the effects of the 24-hour-a-day operation of the steel mills in the area.” G. Alec Stewart, dean of the University Honors College, took yet a different tack, “It would make a stunning addition to the night skyline of Pittsburgh if we were able to illuminate it [the Cathedral of Learning] as significant monuments are in other major cities,” comparing it to the Washington Monument.8
So, what are some of the significant tradeoffs with respect to the Cathedral of Learning?
1. Clean the building artificially in the short term or let Nature do it over time.
2. Clean the building to blend into the cityscape and thus forego the sense of familiarity or maintain the soot-derived appearance and thus avoid rapid change.
3. Trade the sooty, vegetation-free exterior for an exhaust-enriched, vegetation-covered exterior of the building, and thereby give up a sense of Pittsburgh’s 100-year history.
4. Illuminate the Cathedral of Learning from the outside to create a monument-like effect, such as the Washington Monument in the District of Columbia, or keep the status quo.
In the end, each of these tradeoffs is couched in terms of whether to change or not, based largely on some culture value that blends naturally into an emotional criterion.
Other relationships have much more discernable tradeoffs. Take the springtime ozone hole over Antarctic as illustrative; it is finally shrinking after years of growing. As the hole grew in size due to the human-induced, ozone-destroying chemicals in the stratosphere, the risk of skin cancer increased because more ultraviolet radiation reached the Earth. Although today the good news is that the ozone hole is now shrinking and, through a complicated cascade of effects, could fully close within this century, what about tomorrow? Because the hole in the stratospheric ozone layer does not absorb much ultraviolet radiation, it keeps the temperature of Antarctica much cooler than normal. A completely recovered ozone layer, on the other hand, could significantly boost atmospheric warming over and around the icy continent and ostensibly augment its melting.9 In this case, what is good for humans may not be good for Antarctica, and vice versa.
And, speaking of climate, a July 28, 2012, news story gives an example of an unintended, weather-related tradeoff in the Gulf of Mexico—of which there will be many more to come with climate change:
A new report says this year’s Gulf of Mexico “dead zone,” an area of low oxygen that develops every spring and summer, is the fourth-smallest since measurements of the zones began in 1985.
The zone measured 2,889 square miles, according to the report released Friday by the Louisiana Universities Marine Consortium.
The dead zone forms because fertilizer and other nutrients run into the Mississippi River, which empties into the Gulf. The nutrients feed huge numbers of microscopic organisms. When they die, their decomposition uses up oxygen.
Last year’s hypoxic zone was about 6,765 square miles. The record is 8,400.
. . .the dead zone is relatively small this year because record drought across the country meant fewer nutrients were washed into the river—not because needed steps have been taken to prevent the runoff.10
So it is that every weather-/climate-related change—regardless of human desires—has tradeoffs. In that, humanity has no choice. The question is: How do our decisions and subsequent actions affect the tradeoffs—and why?
Text © by Chris Maser 2010. All rights reserved.
This series of blogs is excerpted from my 2009 book, Social-Environmental Planning: The Design Interface Between Everyforest and Everycity, CRC Press, Boca Raton, FL. 321 pp.