OVERVIEW
The Planet Earth system
Scott Lehman
Department of Geological Sciences
Institute of Arctic & Alpine Research - INSTAAR
Lehman
webpage at INSTAAR
Offices
Benson Earth Sciences (BESC), Room 246F
ph. 492-5478. Office Hours: 2:00 – 3:00 P.M TR,
or by e-mail (best) or phone
appointment.
East Campus, RL-1 (INSTAAR), Room 157
ph. 492-8980
Earth as a system
Over the past decade there has been an increasing recognition that Planet Earth is best considered a system, composed of multiple components and inter-connected processes. The major components of the Earth System are the geosphere (the solid earth), the hydrosphere (oceans, glaciers & ice sheets, rivers, lakes, and groundwater), and the atmosphere, all of which interact with the biosphere. No component of this system can be studied in isolation of the others. And, a change in any element of the system has an impact through all components. The realization that we live in such a complex, interdependent system has fostered interdisciplinary research, where biologists work side-by-side with geologists and atmospheric chemists, for example, on a single question. Interdisciplinary teaching is trying to catch up.
The role of humans
The other remarkable change that has become apparent recently is the role of humans in this system. No longer are we considered passive inhabitants of our planetary system. Our steady progress in technological development has elevated our involvement to an active position, and for better or worse, humans are now considered an important component of the Earth System. Human activity is changing the composition of the atmosphere and altering the surface characteristics of the continents, particularly in the primary agricultural regions of the planet. What we are less sure of are the consequences of these changes. We want to know if our activities will have a negative long-term impact on the ability of Planet Earth to sustain life, and particularly to sustain human civilization. Yet we have a very short record by which to measure change. Globally distributed reliable historical records generally extend back no more than 100 years.
This course builds on GEOL-1010
GEOL-1060 builds on the foundations of Earth Science established in GEOL-1010, in which the fundamental physical processes that have shaped our planet are introduced. GEOL-1060 will look in more detail at the mechanisms that control the motion and composition of the atmosphere and oceans. To provide a longer perspective on the range of natural variability in the Earth System, we will use the records of past environments preserved in various geological archives around the planet. These records allow us to learn from grand natural experiments, such as ice ages, huge volcanic eruptions, and changes in major element cycles that have occurred in the not-too-distant past. Finally, the record of past environmental change allows us to evaluate various models that have been developed to predict future changes. These models must be able to accurately predict the way Planet Earth behaved during an ice age, for example, if they are going to be able to correctly predict, how the world might change in the future with changed conditions such as increased atmospheric CO2.