The history of our planet is divided between the distant past and the recent past. The techniques of paleontology and geology are focused on studying the environmental and ecological settings of millions of years ago and large-scale patterns: movements of tectonic plates, changes in the geometry of the earth's orbit, cycles of flora and fauna, evolutionary patterns, etc. The ancient geography of our planet has changed over the course of time. Its characteristics can be reconstructed through the use of detailed studies of evidence from the past, including analysis of rocks, fossil studies, chemical and physical analysis of sediment and concretion, computer simulations and other methods.
The study of the recent past is focused on the time period in which human beings have been active agents on the planet and covers changes in the environment over hundreds of years. Environmental archaeology allows a detailed understanding of the complex interaction between human beings and the environment. This sub-discipline covers various specializations that focus on particular elements: paleoclimatology, paleobotany, geoarchaeology (which includes paleo soils, sedimentology and geomorphology) and paleohydrology (which includes oceanography, hydrogeology and limnology).
The study of the environment of the past considers the changes in the climate, the ecology of plants and animals, and changes in topography and bodies of water. Climate change leads to changes in temperature, precipitation, wind intensity and patterns, and the occurrence (intensity and frequency) of exceptional meteorological events such as hurricanes and storms. Other elements that are directly affected by climate changes are the patterns of ocean currents, including the emergence of cold water, atmospheric phenomenon such as El Niño and La Niña, the volume of ocean water and the relative sea levels at a micro-local level. Geography and hydrology change with the climate, plants and animals adjust and the ecological makeup of the landscape changes. Human beings are not a passive element. Domestic human activity changes the landscape and generates changes in the ecology and in the populations of plants and animals, which results in a composition more favorable and productive for humans.
There are two sources of information for studying the environment of the past: computer simulations and paleodata. The analysis of paleodata studies the empirical evidence of changes in the composition of the atmosphere (including dust particles), geomorphology, environmental deposits and vegetation, all evidence that reflects changes in the parameters of the climate. These data include: pollen, carbon particles, isotope analysis (C, Ca, O, Be, Sr), especially in coral and cave formations, growth rings in trees, sediments and mineral traces. The study of the flora and fauna of the past presents difficulties due to organic degradation after the plant or animal dies. Plants possess distinctive elements that survive degradation and can be recovered with careful study. For animals, bones and anatomical elements may survive in exceptional conditions that lead to preservation.
All of the planet's environments have been impacted in one way or another by human activity. There is practically no place on the planet that can be considered pristine. Gaining a long-term perspective on how the environment has changed over time and how humans have caused, affected or survived those changes can provide tools for understanding how similar situations, in the present or in the future, could affect us as individuals and as societies.
Autor: Reniel Rodríguez Ramos
Published: December 20, 2011.