Geography Reference
In-Depth Information
Summary
What will the future be like? Many would agree with geographer Robert Kates, who
foresees a “warmer, more crowded, more connected but more diverse world.” As we
consider this prospect, we must acknowledge that global environmental changes illus-
trate the limits what we know about our planet. Global environmental change is not
always anticipated and is often nonlinear. Some changes are “chaotic” in the sense that
future conditions cannot be reliably predicted. Nonlinearity means that small actions
in certain situations may result in large impacts and may be more important than larger
actions in causing change. Thresholds also exist in many systems, which, once past, are
irreversible. Irreversible changes occur, for example, when the habitat for a species is
diminished to the point where the species quickly dies off. Unfortunately, we may not
be able to identify these thresholds until we pass them. This leaves open the possibility
of “surprises”—unanticipated responses by physical systems.
The complexity and urgency of environmental change will tax the energies of the
scientifi c and policy communities for some time to come. Geography must be an essen-
tial part of any serious effort to grapple with these challenges. The major changes that
are taking place have different origins and spatial expressions, and each results from a
unique combination of physical and social processes. We cannot simply focus on sys-
tem dynamics and generalized causal relationships. We must also consider emerging
patterns of environmental change and the impacts of differences from place to place on
the operation of general processes. Geography is not the backdrop to the changes tak-
ing place; it is at the very heart of the changes themselves.
Geographic Concepts
chlorofl uorocarbons
anthropocene
Pangaea
tectonic plates
photosynthesis
mass depletions
mass extinctions
Pacifi c Ring of Fire
Pleistocene
glaciation
interglacials
Wisconsinan Glaciation
Holocene
Little Ice Age
greenhouse effect
environmental stress
renewable resources
nonrenewable resources
aquifers
hydrologic cycle
aquifers
atmosphere
acid rain
oxygen cycle
deforestation
soil erosion
solid waste
sanitary landfi lls
toxic waste
radioactive waste
biodiversity
rare earth elements
ozone layer
Vienna Convention for
the Protection of the
Ozone Layer
Montreal Protocol
Learn More Online
About geography and environmental hazards
http://www.bbc.co.uk/scotland/education/int/geog/envhaz/index.shtml
Kilauea Volcano
“Kilauea has been erupting almost continuously since 1983, making it one of Earth's most
active volcanoes. After fl ying over the volcano in a helicopter and looking down at the
