physical geography

PHYSICAL GEOGRAPHY IS AN integral part of a much larger area of understanding called geography. Most individuals define geography as a field of study that deals with maps. This definition is only partially correct. A better definition of geography may be the study of natural and human phenomena relative to a spatial dimension. The discipline of geography has a history that stretches over many centuries. Over this time period, the study of geography has evolved and developed into an important form of human scholarship. Examining the historical evolution of geography as a discipline provides some important insights concerning its character and methodology. These insights are also helpful in gaining a better understanding of the nature of physical geography.

Physical geography, a subdiscipline of geography, is a field of knowledge that studies natural features and phenomena on the Earth from a spatial perspective. It primarily focuses on the spatial patterns of weather and climate, soils, vegetation, animals, water in all its forms, and landforms. Physical geography also examines the interrelationships of these phenomena to human activities. This subfield of geography is academically known as the Human-Land Tradition, and has seen very keen interest and growth in the last few decades because of the acceleration of human-induced environmental degradation. Thus, physical geography's scope is much broader than the simple spatial study of nature. It also involves the investigation of how humans are influencing nature. In other words, it focuses on geography as an Earth science, making use of biology to understand global flora and fauna pattern, and mathematics and physics to understand the motion of the Earth and its relationship with other bodies in the solar system. It also includes landscape ecology and environmental geography.

Thus, the discipline, in a sense, is better organized than its human or social counterpart because it rests upon specialist sciences like geology and meteorology which had made great progress. There is no dearth, but rather an embarrassing wealth, of material out of which to construct the subject.

HISTORICAL OVERVIEW

Some of the first truly geographical studies occurred more than 4,000 years ago. The main purpose of these early investigations was to map features and places observed as explorers traveled to new lands. At this time, Chinese, Egyptian, and Phoenician civilizations were beginning to explore the places and spaces within and outside their homelands. The earliest evidence of such explorations comes from the archaeological discovery of a Babylonian clay tablet map that dates back to 2300 B.C.E.

The early Greeks were the first civilization to practice a form of geography that was more than mere mapmaking or cartography. Greek philosophers and scientists were also interested in learning about spatial nature of human and physical features found on the Earth. One of the first Greek geographers was Herodotus (circa 484–425 B.C.E.). Herodotus wrote a number of volumes that described the human and physical geography of the various regions of the PERSIAN EMPIRE.

The ancient Greeks were also interested in the form, size, and geometry of the Earth. Aristotle (c. 384–322 B.C.E.) hypothesized and scientifically demonstrated that the Earth had a spherical shape. Evidence for this idea came from observations of lunar eclipses. Lunar eclipses occur when the Earth casts its circular shadow on to the moon's surface. The first individual to accurately calculate the circumference of the Earth was the Greek geographer Eratosthenes (c. 276–194 B.C.E.). Eratosthenes calculated the equatorial circumference to be 25,000 mi (40,233 km) using simple geometric relationships. This primitive calculation was unusually accurate. Measurements of the Earth using modern satellite technology have computed the circumference to be 24,899.5 mi (40,072 km).

Most of the Greek accomplishments in geography were passed on to the Romans. Roman military commanders and administrators used this information to guide the expansion of their empire. The Romans also made several important additions to geographical knowledge. Strabo (circa 64 B.C.E.–20 C.E.) wrote a 17-volume series called Geographia. Strabo claimed to have traveled widely and recorded what he had seen and experienced from a geographical perspective. In his series of books, Strabo describes the cultural geographies of the various societies of people found from Britain to as far east as INDIA, and south to ETHIOPIA and as far north as ICELAND. He also suggested a definition of geography that is quite complementary to the way many human geographers define their discipline today. This definition suggests that the aim of geography was to describe the known parts of the inhabited world and to write the assessment of the countries of the world with clearly highlighting the differences between countries.

During the 2nd century C.E., PTOLEMY (c. 100–178) made a number of important contributions to geography. Ptolemy's publication, Geographike hyphegesis (Guide to Geography), compiled and summarized much of the Greek and Roman geographic information accumulated at that time. Some of his other important contributions include the creation of three different methods for projecting the Earth's surface on a map, the calculation of coordinate locations for some 8,000 places on the Earth, and development of the concepts of geographical latitude and longitude.

Little academic progress in geography occurred after the Roman period. For the most part, the Middle Ages (5th to 13th centuries) were a time of intellectual stagnation. In Europe, the Vikings of Scandinavia were the only group of people carrying out active exploration of new lands. In the Middle East, Arab academics began translating the works of Greek and Roman geographers starting in the 8th century and exploring southwestern Asia and Africa. Some of the important intellectuals in Arab geography were Al-Idrisi, IBN BATTUTA, and Ibn Khaldun. Al-Idrisi is best known for his skill at making maps and for his work of descriptive geography. Ibn Battuta and Ibn Khaldun are well known for writing about their extensive travels to North Africa and the MIDDLE EAST.

RENAISSANCE

During the Renaissance (1400 to 1600), numerous journeys of geographical exploration were commissioned by a variety of nation-states in Europe. Most of these voyages were financed because of the potential commercial returns from resource exploitation. The voyages also provided an opportunity for scientific investigation and discovery and added many significant contributions to geographic knowledge. Important explorers of this period include Christopher Columbus, Vasco da Gama, Ferdinand MAGELLAN, Jacques Cartier, Sir Martin Frobisher, Sir Francis Drake, John and Sebastian Cabot, and John Davis. Also during the Renaissance, Martin Behaim created a spherical globe depicting the Earth in its true three-dimensional form in 1492. Prior to Behaim's invention, it was commonly believed in the Middle Ages that the Earth was flat. Behaim's globe probably influenced the beliefs of navigators and explorers of that time because it suggested that one could travel around the world.

In the 17th century, Bernhardus Varenius (1622–50) published an important geographic reference titled Geographia generalis (General Geography, 1650). During the 18th century, the German philosopher Immanuel Kant (1724–1804) proposed that human knowledge could be organized in three different ways. One way of organizing knowledge was to classify its facts according to the type of objects studied. Accordingly, zoology studies animals, botany examines plants, and geology involves the investigation of rocks. The second way one can study things is according to a temporal dimension. This field of knowledge is of course called history. The last method of organizing knowledge involves understanding facts relative to spatial relationships. This field of knowledge is commonly known as geography. Kant also divided geography into a number of subdisciplines. He recognized the following six branches: physical, mathematical, moral, political, commercial, and theological geography.

Geographic knowledge saw strong growth in Europe and the UNITED STATES in the 1800s. This period also saw the emergence of a number of societies interested in geographic issues. In GERMANY, Alexander von HUMBOLDT, Karl Ritter, and Friedrich Ratzel made substantial contributions to human and physical geography. Humboldt's publication Kosmos (1844) examines the geology and physical geography of the Earth. This work is considered by many academics to be a milestone contribution to geographic scholarship.

Late in the 19th century, Ratzel theorized that the distribution and culture of the Earth's various human populations were strongly influenced by the natural environment. The French geographer Paul Vidal de la Blanche opposed this revolutionary idea. Instead, he suggested that human beings were a dominant force shaping the form of the environment. The idea that humans were modifying the physical environment was also prevalent in the United States. In 1847, George Perkins Marsh gave an address to the Agricultural Society of Rutland County, VERMONT. The subject of this speech was that human activity was having a destructive impact on land, especially through deforestation and land conversion. This speech also became the foundation for his book Man and Nature or The Earth as Modified by Human Action, first published in 1864. In this publication, Marsh warned of the ecological consequences of the continued development of the American frontier.

Many academics in the field of geography extended the various ideas presented in the previous century to studies of small regions all over the world. Most of these studies used descriptive field methods to test research questions. Starting in about 1950, geographic research experienced a shift in methodology. Geographers began adopting a more scientific approach that relied on quantitative techniques. The quantitative revolution was also associated with a change in the way in which geographers studied the Earth and its phenomena. Researchers now began investigating process rather than mere description of the event of interest. Today, the quantitative approach is becoming even more prevalent because of advances in computer and software technologies.

The history and development of geography, discussed above, suggest a definition that geography, in its simplest form, is the field of knowledge that is concerned with how phenomena are spatially organized. Physical geography attempts to determine why natural phenomena have particular spatial patterns and orientation.

ELEMENTS AND PHENOMENA

Physical geography and HUMAN GEOGRAPHY are the two major subfields of knowledge emanating from the discipline of geography. It is important to distinguish between these two subfields that use similar methodologies. Knowing what kinds of things are studied by geographers provides us with a better understanding of the differences between physical and human geography.

Phenomena or elements studied in physical geography include rocks and minerals, landforms, soils, animals, plants, water, atmosphere, rivers and other water bodies, environment, climate and weather, and oceans. Phenomena or elements studied in human geography include population, setllements, economic activities, transportation, recreational activities, religion, political systems, social traditions, human migration, agricultural systems, and urban systems.

Geography is also a discipline that integrates a wide variety of subject matter. Almost any area of human knowledge can be examined from a spatial perspective. Also, the study of geography can involve a holistic synthesis, which connects knowledge from a variety of academic fields in both human and physical geography.

For example, the study of the enhancement of the Earth's greenhouse effect and the resulting global warming requires a multidisciplinary approach for complete understanding. The fields of climatology and meteorology are required to understand the physical effects of adding additional greenhouse gases to the atmosphere's radiation balance. The field of economic geography provides information on how various forms of human economic activity contribute to the emission of greenhouse gases through fossil fuel burning and land-use change. Combining the knowledge of both of these academic areas gives us a more comprehensive understanding of why serious environmental problems occur.

STRENGTH AND WEAKNESS

The holistic nature of geography is a strength and weakness both. Geography's strength comes from its ability to connect functional interrelationships that are not normally noticed in narrowly defined fields of knowledge. The most obvious weakness associated with the geographical approach is related to the fact that holistic understanding is often too simple and misses important details of cause and effect.

Physical geography's primary subdisciplines study the Earth's atmosphere (meteorology and climatology), animal and plant life (biogeography), physical landscape (geomorphology), soils (pedology), and waters (hydrology). Some of the dominant areas of study in human geography include human society and culture (social and cultural geography), behavior (behavioral geography), economics (economic geography), politics (political geography), and urban systems (urban geography).

SPECIALIZATION

Academics studying physical geography and other related earth sciences are rarely generalists. Most are in fact highly specialized in their fields of knowledge and tend to focus themselves in one of the following well defined areas of understanding in physical geography.

The fields of knowledge generally have a primary role in introductory textbooks dealing with physical geography. Introductory textbooks can also contain information from other related disciplines including geology— the study of the form of the Earth's surface and subsurface and the processes that create and modify it; ecology—the scientific study of the interactions between organisms and their environment; oceanography— the science that examines the biology, chemistry, physics, and geology of oceans; cartography—the technique of making maps; and astronomy—the science that examines nature, motion, origin, and constitution celestial bodies and the cosmos.

After 1950, the following two forces largely determined the nature of physical geography:

The Quantitative Revolution. Measurement became the central focus of research in physical geography. It was used primarily for hypothesis testing. With measurement came mapping, models, statistics, mathematics, and hypothesis testing. The quantitative revolution was also associated with a change in the way in which physical geographers studied the Earth and its phenomena. Researchers now began investigating process rather than mere description of the environment.

The Study of Human/Land Relationships. The influence of human activity on the environment was becoming very apparent after 1950. As a result, many researchers in physical geography began studying the influence of humans on the environment. Some of the dominant themes in these studies included environmental degradation and resource use; natural hazards and impact assessment; and the effect of urbanization and land-use change on natural environments.

UNDERSTANDING PHYSICAL GEOGRAPHY

The nature of understanding in physical geography has changed over time. When investigating this change, it becomes apparent that certain universal ideas or forces had very important ramifications to the academic study of physical geography.

During the period from 1850 to 1950, there were five main ideas that had a strong influence on the discipline:

Uniformitarianism. This theory rejected the idea that catastrophic forces were responsible for the current conditions on the Earth. It suggested instead that continuing uniformity of existing processes were responsible for the present and past conditions of this planet.

Evolution. Charles Darwin's Origin of Species (1859) suggested that natural selection determined which individuals would pass on their genetic traits to future generations. As a result of this theory, evolutionary explanations for a variety of natural phenomena were postulated by scientists. The theories of uniformitarianism and evolution arose from a fundamental change in the way humans explained the universe and nature.

During the 16th, 17th, and 18th centuries, scholars began refuting belief- or myth-based explanations of the cosmos and instead used science to help explain the mysteries of nature. Belief-based explanations of the cosmos are made consistent with a larger framework of knowledge that focuses on some myth. However, theories based on science questioned the accuracy of these beliefs.

Exploration and Survey. Much of the world had not been explored before 1900. Thus, during this period all of the fields of physical geography were actively involved with basic data collection. This data collection included activities like determining the elevation of land surfaces, classification and description of landforms, the measurement of the volume of flow of rivers, measurement of phenomena associated with weather and climate, and the classification of soils, organisms, biological communities, and ecosystems.

Conservation. Beginning in the 1850s, a concern for the environment began to develop as a result of the human development of once natural areas in the United States and Europe. One of the earliest statements of these ideas came from George Perkins Marsh (1864) in his book Man in Nature or Physical Geography as Modified by Human Action. This book is often cited by scholars as the first significant academic contribution to conservation and environmentalism.

Systems Theory. The world of nature is very complex. In order to understand this complexity, humans usually try to visualize the phenomena of nature as a system. A system is a set of interrelated components working together toward some kind of process. One of the simplest forms of a system is a model. Both models and systems are simplified versions of reality. The interaction between perceptible phenomena and theory is accomplished through explanation and validation. This simple model, while an extreme abstraction of reality, illustrates how scientific understanding works. It suggests that in scientific understanding, perceptible phenomena and theory interact through explanation and validation.

In physical geography and many other fields of knowledge, systems and models are used extensively as aids in explaining natural phenomena around us. A system is a group of parts that interact according to some kind of process. Systems are often visualized or modeled as component blocks with some kind of connections drawn. All systems have the same common characteristics. These common characteristics are summarized below:

All systems have some structure.

All systems are generalizations of reality.

They all function in the same way.

There are functional as well as structural relationships between the units of a system.

Function implies the flow and transfer of some material.

Systems exchange energy and matter internally and with their surrounding environment through various processes of input and output.

Function requires the presence of some driving force or some source of energy.

All systems show some degree of integration.

Within its defined boundary the system has three kinds of properties: Elements are the kinds of things or substances composing the system. They may be atoms or molecules or larger bodies of matter—sand grains, rain drops, plants, or cows. Attributes are characteristics of the elements that may be perceived; for example: quantity, size, color, volume, temperature, and mass. Relationships are the associations that exist between elements and attributes based on cause and effect.

The state of the system is defined when each of its properties (for example, elements, attributes, and relationships) has a defined value. Scientists have examined and classified many types of systems. These types include the isolated system, a system where there are no interactions outside its boundary layer. Such systems are common in laboratory experiments. A closed system is closed with respect to matter, but energy may be transferred between the system and its surroundings. Earth is essentially a closed system. An open system is a system where both matter and energy can cross the boundary of the system. Most environmental systems are open.

A morphological system is a system where we understand process relationships or correlations between the elements of the system in terms of measured features. A cascading system concerns the movement of energy and/or matter from one element to another and understands the processes involved. A process-response system involves the movement, storage, and transformation of energy and matter and the relationships between measured features in the various elements of the system. A control system is a system that is intelligently manipulated by humans. An ecosystem is concerned with the biological relationships within the environment and the interactions between organisms and their physical surroundings.

STRUCTURE OF SYSTEMS

Systems exist at every scale of size and are often arranged in some kind of hierarchical fashion. Large systems are often composed of one or more smaller systems working within its various elements. Processes within these smaller systems can often be connected directly or indirectly to processes found in the larger system. A good example of a system within systems is the hierarchy of systems found in the universe.

At the highest level in this hierarchy, we have the system that we call the cosmos or universe. The elements of this system consist of galaxies, quasars, black holes, stars, planets, and other heavenly bodies. The current structure of this system is thought to have come about because of a massive explosion known as the Big Bang and is controlled by gravity, weak and strong atomic forces, and electromagnetic forces.

Around some stars in the universe we have an obvious arrangement of planets, asteroids, comets, and other material. We call these systems solar systems. The elements of this system behave according to set laws of nature and are often found orbiting around a central star because of gravitational attraction. On some planets conditions may exist for the development of dynamic interactions between the hydrosphere, lithosphere, atmosphere, or biosphere.

We can define a planetary system as a celestial body in space that orbits a star and that maintains some level of dynamics between its lithosphere, atmosphere and hydrosphere. Some planetary systems, like the Earth, can also have a biosphere. If a planetary system contains a biosphere, dynamic interactions will develop between this system and the lithosphere, atmosphere, and hydrosphere. These interactions can be called an environmental system. Environmental systems can also exist at smaller scales of size (for example, a single flower growing in a field could be an example of a small-scale environmental system).

The Earth's biosphere is made up of small interacting entities called ecosystems. In an ecosystem, populations of species group together into communities and interact with each other and the abiotic environment. The smallest living entity in an ecosystem is a single organism. An organism is alive and functioning because it is a biological system. The elements of a biological system consist of cells and larger structures known as organs that work together to produce life. The functioning of cells in any biological system is dependent on numerous chemical reactions. Together these chemical reactions make up a chemical system. The types of chemical interactions found in chemical systems are dependent on the atomic structure of the reacting matter. The components of atomic structure can be described as an atomic system.

ENVIRONMENTAL SYSTEMS

An environmental system is a system where life interacts with the various abiotic components found in the atmosphere, hydrosphere, and lithosphere. Environmental systems also involve the capture, movement,
storage, and use of energy. Thus, environmental systems are also energy systems. In environmental systems, energy moves from the abiotic environment to life through processes like plant photosynthesis. Photosynthesis packages this energy into simple organic compounds like glucose and starch. Both of these organic molecules can be stored for future use.

The chemical energy of photosynthesis can be passed on to other living or biotic components of an environmental system through biomass consumption or decomposition by consumer organisms. When needed for metabolic processes, the fixed organic energy stored in an organism can be released to do work via respiration or fermentation. Energy also fuels a number of environmental processes that are essentially abiotic: for example, the movement of air by wind, the weathering of rock into soil, the formation of precipitation, and the creation of mountains by tectonic forces. The first three processes derive their energy directly or indirectly from the sun's radiation that is received at the Earth's surface. Mountain building is fueled by the heat energy that exists within the Earth's interior. Finally, the movement of energy in environmental systems always obeys specific thermodynamic laws that cannot be broken.

It is understood that environment is the complex of physical, chemical, and biotic factors (such as climate, soil, and living things) that act upon an organism or an ecological community and ultimately determines its form and survival. Both human and physical geography provide an important intellectual background for studying the environment. Many environmental studies/ science programs offered by universities and colleges around the world rely on the information found in various geography courses to help educate their students about the state of the environment.

FUTURE OF PHYSICAL GEOGRAPHY

The following describes some of the important future trends in physical geography research:

Applied geography. Continued development of applied physical geography will help analyze and correct human-induced environmental problems. A student of applied physical geography uses theoretical information from the field of physical geography to manage and solve problems related to natural phenomena found in the real world.

Remote sensing. Advances in technology have caused the development of many new instruments for the monitoring of the Earth's resources and environment from airborne and space platforms. The most familiar use of remote sensing technology is to monitor the Earth's weather for forecasting.

Geographic Information Systems. A GEOGRAPHIC INFORMATION SYSTEM (GIS) merges information in a computer database with spatial coordinates on a digital map. Geographic Information Systems are becoming increasingly more important for the management of resources.