Geography is an academic discipline that traces its roots to classical Greece. The Greek scholar Eratosthenes (275-195 b.c.e.) is usually identified as the father of geography. He coined the term geography, which is derived by combining the Greek noun for Earth (geo) with the Greek verb "to write" (graphein). Literally translated, geography means to write or describe the Earth. Based on his travels up the Nile River and his knowledge of geometry, he was able to accurately calculate the circumference of the Earth.
Since the time of the ancient Greeks, geography has evolved into a varied discipline with many research subjects and methodologies. Some scholars have attempted to impose a narrow definition on the sprawling reach of geography. However, other geographers suggest that four research traditions have evolved within the discipline, all of which examine the regional dimensions of human and/or physical processes on the surface of the Earth. These themes include: physical geography or environmental science, the primary emphasis on natural processes such as hydrology, geomorphology, meteorology, and biogeography; spatial science, using deductive mathematical models, geographic information system (GIS) and global positioning system (GPS) technologies, remote sensing, and statistical analyses to study terrestrial processes; nature-society relations, focusing on the interface between human activities and environmental changes; and regional geography, examining people, places, and regions using an array of methodologies.
There is overlap between these traditions. The organization of geographical research into these four broad themes has been affirmed by Association of American Geographers (AAG), the preeminent American organization of academic geographers, who have organized the subsections of their flagship journal, the Annals of the AAG, to roughly correspond to these divisions. The Royal Geographical Society (RGS), the British counterpart to the AAG, and other organizations of academic geographers largely agree with this sweeping definition of Geography. Given the broad reach and crosscutting nature of the discipline, it is appropriate to view global warming through the prism of geography.
Physical geography
Physical geographers have studied the causes and consequences of global warming from different perspectives, including biogeography, the cryosphere, geomor-phology, and hydrology. For example, biogeographers have studied how rising temperatures or changing precipitation regimes will affect entire plant ecosystems or biomes such as boreal forests. They have also examined how specific plant species will cope under different climate conditions. In many instances, the research predicts that warm-weather plant species will successfully migrate toward higher latitudes. On the other hand, some cool-weather plant species found at high altitudes may die out if they are not able to ascend beyond a certain elevation to avoid the heat.
Geomorphologists suggest that global climate change could have drastic impacts on river flows, coastlines, and soils. These studies of fluvial and coastal geomorphology suggest that increased precipitation will increase flooding and soil erosion. This will, in turn, affect agriculture and other human activities.
Geographers who study the cryosphere (frozen regions of the Earth) predict large changes as a result of melting permafrost and melting glaciers. Forests and other plant ecosystems that were once protected from insects and other pathogens by freezing temperatures could be at risk as temperatures rise. If there is large-scale die-off from newly-invasive pests, dying trees can become a fire hazard.
Climatologists have focused on the potential of more frequent and more intense hurricanes and other weather events. Other topics within this subgenre of geography include the likelihood of droughts in China, and the predictions of local and regional-scale temperature variations across the globe. Of course, climatologists have been at the forefront of research documenting the existence of global warming. Climatologists have used maps to study geographic variations in oceanic temperatures and to predict future changes to ocean currents such as the Gulf Stream.
Spatial science: methods, models and gis
Geographers have always relied on maps to display their research findings. Research on global warming is no different. In fact, computer cartography, GIS, and remote sensing are widely used by climatolo-gists, trained in many disciplines, as a way to catalogue the evidence for climate change in the past and to organize evidence for climate change now and into the future. Geographers can construct mathematical models that incorporate many independent variables related to temperature, precipitation, topography, atmospheric gases, population growth, industrial development, and rates of deforestation, to predict how the manifestations of climate change will vary by geographic scale and region.
Some of the data needed to build these models, such as historic temperature records, can be gleaned from secondary sources. However, much of the data needed, such as land cover or atmospheric gas composition, needs to be gathered using satellite images and other remote-sensing techniques. Satellite imagery is particularly useful for detecting changes in vegetation. Vegetation stressed due to drought, disease, or human activity can be detected using infrared filters on satellite images.
Maps, the stock-in-trade of geographers, are used by every major research and policy agency on the planet, including the U.S. Environmental Protection Agency (EPA), the U.S. Department of Agriculture (USDA), the United Nations Food and Agriculture Organization (FAO), the European Space Agency (ESA), and the National Aeronautical and Space Agency (NASA) to display information related to global warming. NASA websites offer online cartographical movie clips that show future scenarios for regional impacts of climate change.
Nature and society
Geographers in this subgroup are interested in the human dimensions of global change. They are interested in the human causes and consequences of global warming. Consider the issue of water resources. The uneven distribution of water resources has caused many political confrontations in the past. Water scarcity and related water diversion projects in California, the former Soviet Union, and along the Nile River have all created regional and/or international political strife. Global warming is likely to exacerbate these issues as precipitation decreases further in some places and intensifies in others. Water resource geographers attempt to understand how human behaviors affect water supplies and how policies can be crafted to increase the supply of potable water to those who need it most.
An understanding of the geography of energy production and consumption is central to understanding the causes and consequences of global warming. Energy geography will also be essential to the development of strategies to combat global warming. Energy geographers work with climatologists to identify places with good wind energy potential. Some communities actively recruit wind power development. Others are not so sanguine. Hence, energy geographers work with land-use planners to find sites for wind turbines that are energy efficient and acceptable to communities in the area.
Geographers interested in natural resource management, tourism, and recreation also have an interest in global warming. Ski resorts increasingly rely on artificial snow to extend their seasons because of declining winter precipitation. Hence, some ski resorts may be forced out of business if alternative water supplies cannot be found. Large inland bodies of water are also affected by climate change. In 2007, the water levels in Lake Superior reached record lows. Declining water levels hinder navigation and beach access for recreation and commerce. This could have dire economic consequences for many communities that depend on tourism dollars.
Coastal and marine geographers study how temperature changes could increase sea levels, the intensity of hurricanes, and the extent of beachfront erosion. Many beach communities along the Atlantic Coast spend millions of dollars replenishing beaches that have been destroyed by severe wave action. If sea levels rise and storms become more intense, these communities will have to spend even more money maintaining their coastlines.
Damage and flooding to coastlines as a result of climate change will, of course, do more than just affect tourism. There are many large cities and population centers that exist, near or even below, sea level. Examples of at-risk regions certainly include Bangladesh, islands of the Indian Ocean, such as the Maldives, but also the Netherlands, the Florida Keys, and large cities of North America and Western Europe including New Orleans, New York City, Venice, and Copenhagen.
Regional geography: people, place, and region
Scholars from the human geography tradition examine the political, economic, demographic, and cultural implications of climate change. For centuries, explorers have attempted to find a Northwest Passage that would shorten the sailing distance between Europe and Asia. Explorers such as Henry Hudson believed that a route existed through the Arctic Ocean along Canada’s northern coast. He failed to find it, as did dozens of other explorers of note. In fact, severe weather and thick pack ice proved to be an impenetrable barrier to commercial shipping through the 20th century.
However, there is evidence to suggest that rising temperatures will melt the pack ice in the Arctic Ocean, allowing the Northwest Passage to become a viable commercial navigation route. However, there are serious geopolitical issues to resolve as Canada has declared that the passage exists entirely within Canadian waters. Other countries, such as the United States and European countries, claim that the route is an international channel independent of Canadian sovereignty. While nation-states quarrel over who has sovereignty over northern seaways, the plight of Inuit cultures goes largely unnoticed. However, many of the traditional hunting rituals and life-ways depend on frozen sea ice. However, rising sea levels and a longer ice-free summer season are causing coastal erosion that is forcing indigenous communities to relocate and adapt.
Global warming will also have economic impacts that vary regionally. Panama is currently investing hundreds of millions of dollars expanding its famous canal. However, if the Northwest Passage does become commercially viable, this might undermine the ability of Panama to recoup its investments in an enlarged canal. Other cities that depend on oceanic trade, such as Singapore and Hong Kong, may suffer economically as trade is diverted away from Southeast Asia northward through the Arctic Ocean.
Global warming may have profound impacts on where people live. Rising sea levels may force millions of people to relocate to higher ground. Changing patterns of precipitation may affect the livability of inland cities such as Phoenix, Arizona; Denver, Colorado; or Las Vegas, Nevada. These are rapidly growing cities located in arid and semi-arid environments. Phoenix and Las Vegas depend on water that is diverted many hundreds of miles. If water sources decline, this will limit the economic and demographic growth of these cities.
An important aspect of understanding geographic variation is how seemingly meaningless regional differences can become a basis for deep social inequality. Hence, a geographic perspective can help to understand, and possibly remediate, the social and regional injustices that could occur from global climate change. Hurricane Katrina and the fate of the residents of New Orleans have already given us a foretaste of how regional differences get translated into social inequalities. In the case of New Orleans, the people most severely affected were poor and from minority neighborhoods. Public health will also be affected by climate change, because a changing climate will likely cause diseases to shift into new regions. It will be the wealthy people and countries that will be most able to adapt. Global climate change will likely worsen existing inequalities. This dynamic may be repeated at different scales in different regions unless a geographic perspective is used to implement policies that promote a more egalitarian policy response to climate change.
