Sunday, April 28, 2013

Earth's Evolving Landscape

From the moment of its formation, 4.6 billion years ago, Planet Earth's surface has been continuously molded by natural forces.  Plate tectonics has opened and closed oceans, lifted mountain ranges, torn continents apart and produced a wide variety of volcanic terrain.  At the same time, streams, rivers, wind, waves and glaciers have been eroding the landforms, leveling highlands, sculpting rock formations, opening caves, carving canyons and revising shorelines.  Finally, the interplay of climate, latitude, soil condition, wildfire, precipitation and other factors determine the changing mosaic of surface vegetation which, in turn, governs regional fauna populations.

During our brief lifespans we barely notice significant changes in Earth's landscape except for features that we, as a species, have produced: reservoirs, canals, man-made canyons, tunnels, agricultural fields and construction related to our towns and cities.  Active volcanic eruptions, earthquakes, floods, rockfalls, tsunamis, mudslides, hurricanes and other natural phenomena offer intermittent evidence of the forces that shape our planet but the concept of plate tectonics is difficult to comprehend during our brief lives.

Indeed, it is our short-term perspective that tricks us into believing that we can control (or at least manage) the forces of nature.  Convinced that we can prevent flooding with dams and levees, we build cities on floodplains.  Confident that we can divert water from distant rivers and underground aquifers indefinitely, we develop resorts, golf courses and sprawling suburbs in desert landscapes.  Oblivious to the power of hurricanes and tropical storms, we construct homes along coastlines and on barrier islands.  Betting against rockslides, avalanches and wildfires, we establish towns on rugged mountains slopes.  Most of us luck out; others do not.  In the end, the erratic yet relentless evolution of our planet continues and nature neither targets nor spares human communities.