precipitation, temperature, wind, and humidity at the earth’s surface. The earth-sun
relationship that defines season combines with latitude, surface cover (land versus sea),
the water cycle, and movement of air masses, to generate global weather patterns. As
opposed to weather that takes place over a short time span, climate represents long-term
trends that are averaged over a time scale of several decades. These trends are classified
into climate types with names indicative of their dominant temperature and precipitation
features. Knowledge of the macroclimate of a representative city or region, in
combination with a qualitative understanding of local microclimate, allows architects,
builders, city planners, and landscape architects to modify indoor and outdoor
environments in ways that improve human comfort, reduce building energy consumption,
and optimize site resource use.
Indigenous builders recognized the relationships between shelter and
climate. James Marston Fitch, in his 1960 Scientific A merican article “Primitive
Architecture and Climate,” clarified the empirical and evolutionary
wisdom of these builders to create efficient, comfortable, climateresponsive
structures in all regions of the world. Fitch also challenged
contemporary architects to demonstrate skill comparable to their
Encyclopedia of 20th-century architecture 512
“primitive” counterparts in designing energy- and resource-efficient
structures that would satisfy their occupants’ needs. This challenge
became the focus of climate-responsive architecture for the 20th century:
to combine the wisdom of indigenous builders with contemporary building
science, technology, and design. The achievements of this era can be
summarized in three main categories: refined regional guidelines for
climate-responsive environmental design; new methods for assessing the
relationship between climate, human comfort, and energy use in buildings;
and an improved understanding of how urban environments influence
climate.
Regional Climate Analyses and Design
Guidelines
The most important contributions advancing architectural knowledge of climatic design
in the 20th century occurred in the post-World War II era. In 1949 the American Institute
of Architects’ House Beautiful Climate Control Project was the first major contribution to the field,
appearing both as a series of articles in the popular press and technical briefs in the Bulletin of the A.I.A.
The principal author of these reports, climatologist Dr. Paul Siple, was hired by the
American Society of Heating and Ventilating Engineers to create regional climate
analyses and design data for a number of U.S. cities and their surrounding areas. The
project—to analyze climatic data in terms of its implications for residential design—was
the first major effort to summarize climate data for use by the architectural design
community.
There have been subsequent publications of regional climatic design
guidelines for buildings and their surrounding environments. The U.S.
Department of Housing and Urban Development contracted with the
American Institute of Architects’ Research Corporation to publish Regional Guidelines fo r Building Pas s ive Energy Conserving Homes
(1980), which provides general climatic design recommendations for the
continental United States and Hawaii. Climatic Des ign (Watson and Labs, 1993) and Sun, Wind and Light
(Brown and Dekay, 2000) use design illustrations, monographs, rules of
thumb, and case study examples to communicate architectural design
strategies that respond to climate. Most works have been inspired by the
ideas presented in the 1963 book Des ign with Climate: Bioclimatic Approach to Arch itectural Regionalism by Victor Olgyay, which has
greatly influenced several generations of architects interested in climatic
design.
Entries A–F 513
Design Methods
The text Des ign with Climate: Bioclimatic Approach to Architectural Regionalism was a substantive addition to the architect’s understanding of climateresponsive
design beyond the provision of design guidelines. The author developed a
quantitative method for assessing human comfort in relationship to exterior climate
conditions. The “Bioclimatic Chart,” as it is called, plots dry-bulb temperature against
relative humidity and delineates a portion of the chart as the “comfort zone”; that is, the
range of thermal conditions in which a sedentary young adult dressed in lightweight
clothing would experience comfort in the shade. For climate conditions outside this zone,
the chart indicates how modifications of sun, wind, and moisture can render comfort in
spite of the naturally occurring conditions. The Bioclimatic Chart still enjoys a place in
architectural design methods although it has evolved through the contributions of others.
Givoni and Milne (1976) showed, in this case adopting the psychometric chart, how
comfort can be achieved indoors through passive and low-energy design strategies. The
relationship between human comfort, acclimatization, and appropriate building strategies
is an emerging field of study as architects and engineers realize the need to optimize both
energy consumption and environmental performance in buildings.
Computer software to analyze regional climate data and their design implications is
another important development in design methods in the 20th century. The most notable
software packages in this category are Climate Consultant from UCLA and
METEONORM from Meteotest. Sources for U.S. climatological data used by these
software packages and by other calculation methods include the National Oceanic and
Atmospheric Administration (NOAA), the National Climatic Data Center (NCDC), and
the National Renewable Energy Laboratory (NREL). When based on actual
measurements, these data are compiled from a sparse observation network of weather
stations on the ground or of sky-based instruments (such as satellites and weather
balloons), typically recorded for agricultural or military purposes. When actual data are
not available, they can be approximated using mathematical or statistical methods.
Typical Meteorological Year (TMY2) data from NREL, for example, are based on actual
measurements and mathematical models. Climate data are instrumental to climate
analysis for building energy simulation software (e.g., Energy-10, Energy Scheming,
Solar-5) that allows designers to estimate the effect of climate on indoor temperatures as
well as building energy consumption. More research is needed for the application of these
data to modeling of microclimates around buildings and open spaces at the city scale.
Climate Modification
Although the effects of urbanization on climate have been noted since Roman
antiquity—from the writings of architect and engi-neer Marcus Vitruvius Pollio in the 1st
century B.C. to the odes of Quintus Horatius Flaccus around 24 B.C.—measurement and
modeling of these effects gained greater attention in the 20th century A.D. Motorized
traverses of urban centers to measure air temperature gradients between cities and their
surrounding rural countrysides began in 1917. The field of urban climatology, which
examines the effect of cities on climate, has emerged as the principal discipline engaged
in this study. Its purpose is to assess the effects of urban buildings, transportation
systems, and industrial activities on the atmospheric and hydrologic cycles and their
associated energy and water balances. Detailed studies of one climate phenomenon in
Encyclopedia of 20th-century architecture 514
particular, the urban heat island effect, preoccupied many scientists and researchers in the
20th century.
Urban heat islands are attributed to a combination of influences that cause air
temperatures in cities to be higher than in surrounding suburban or rural areas. Cities
exhibit increased thermal storage potential, for waste heat as well as incident solar
radiation, by their massive construction materials commonly used in buildings and
streetscapes (such as concrete and asphalt, respectively). The effect is more pronounced
at night because cities have a slower rate of nocturnal radiant cooling than surrounding
rural areas. Finally, cities experience less evaporative cooling because of increased runoff
from paved surfaces and limited vegetation to retain moisture in urban environments. The
urban heat island effect has been documented in cities throughout the world using
satellite imagery and ground-based measurement. Because of the negative effect on
cooling energy consumption in most cities (except in cold climates), design
recommendations, such as white roofs and selective planting, are cited as mitigation
measures for the urban heat island effect.
The question of climate change on a global scale fueled a central debate at the end of
the 20th century. Large computer programs called GCMs (known as General Circulation
or Global Climate Models) were being used by scientists to predict the magnitude of
change in temperature and precipitation for changes in atmospheric concentrations of
carbon dioxide. Evidence of climate change has also been detected in paleoclimatological
records obtained from ice cores, for example. The Interagency Panel on Climate Change
(IPCC), formed in 1988 by the World Meteorological Organization and the United
Nations Environmental Program, continues an internationally coordinated effort to
investigate the hypothesis that surface temperatures worldwide have been increasing as a
result of anthropogenic change and, to a lesser degree, natural climatic variability.
In the last two decades of the 20th century, world leaders and a wide array of
international nongovernmental organizations (NGOs) convened to determine appropriate
policy responses to global climate change. The most notable policy actions resulting from
these landmark events were the 1987 Montreal Protocol to combat ozone depletion, the
1997 Kyoto Agreement for reducing greenhouse gases, and the 1992 Rio Summit
“Agenda 21,” a worldwide plan for global environmental action. The architectural and
planning ramifications of climate change have yet to be translated into discernible
actions, with a few exceptions such as the phasing out of chloro-fluorocarbons (CFCs)
used in building materials and systems.
Environmental sustainability, as an approach to architectural design and urban
planning, has renewed understanding of the importance of climate in the design of
buildings, landscapes, and cities. As a result of developments in the 20th century,
regional guidelines, design methods, and documentation of regional and global climate
phenomena have advanced designers’ abilities to predict environmental performance of
buildings in their surroundings based on climate. From the bioclimatic skyscrapers of
architect Kenneth Yeang to the solar planned subdivision of Village Homes in Davis,
California, climateadapted design has proven to be economically, aesthetically, and
environmentally sound.
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