I would like to emphasize a few things about the course, taken from the course description, which reads, "Selected human impacts on ecosystems are examined in depth."

This raises several important things that you should know about the course:

( 1) This is not a "survey" course, in which we look a little bit at virtually every topic in environmental science. Rather, we will focus in depth on selected topics that are of special importance in a global context.

I have deliberately chosen to include only topics that have global (or at least regional) implications. This means that many important issues that are more local in scope will not be discussed.

Human activities increasingly have effects on much more than one local ecosystem. For example, gases that we produce have potential to change the global climate, deplete the protective ozone layer in the stratosphere, and so forth. I have restricted our coverage to topics that affect wide geographic scales.

This perspective about "what is important" is in contrast to polls of the public, concerning what they believe to be the most pressing environmental problems of the day. Polls frequently show that the public is more concerned about issues such as toxic spills, "superfund sites" and so forth than they are about larger ranging problems such as potential global climate change. That is, the public often tends to be most concerned about problems that are relatively local, fast-behaving, and that involve accidents, toxics, and human health. By contrast, we will be focusing on problems that are larger scale geographically, often relatively slow-behaving, and that have more generalized ecological consequences.

The noted scientist Paul Ehrlich (click to move to the study guide that includes some articles and books by him), argues that this public preoccupation with "crises" is a natural product of our evolution as humans. We evolved to react rapidly to short term "fires" (the "fight or flight response"), but that we are not "programmed" to notice or be alarmed by longer-term trends that are taking place over large geographic scales. He further argues that this human tendency is dangerous, allowing many of our pressing problems to grow without being adequately addressed. For example, human populations continue to grow at very rapid rates in many parts of the world, yet many people don't see this as a crisis. From a human time perspective, the growth doesn't appear to be all that fast; a longer term perspective is required to see it as the crisis that it really is.

(2) Our focus is on impacts on ecosystems , not just on humans, human health, and the quality of human life. That is, this is not directly a human-centered course, except that the causes of the problems are largely human and we humans are affected by ecosystem degradation -- often more than we realize.

(3) We will emphasize scientific rather than legislative perspectives and approaches to the problems that we discuss. We will explore what kinds of data are brought to bear, how are those data are gathered, and what we know about the science of what is happening. We will see that there are several kinds of scientific approaches used to investigate environmental problems; they are often too complex and/or too large scale to be approached with just one method.

Social impacts resulting from each issue and social causes of them will be addressed to a much lesser extent, and we won't focus much on regulation (e.g., legislation) of these environmental problems. Regulatory approaches are the focus of other courses on campus.


(1) Human population growth. In my view, growth of the human population connects to and underlies everything else. It is a primary reason why we as humans have such tremendous impacts on other ecosystems. We will discuss both the history of human population growth (including introduction to basic population parameters) and the current status of the human population.

(2) Selected issues in agriculture. Agriculture connects with human population, in that its impacts result largely from trying to trying to feed all these people! We will look at the "Green Revolution," inputs of pesticides and fertilizers into ecosystems, land degradation associated with agriculture (including that related to grazing by livestock, erosion, and some irrigation strategies), and will finish this unit with some discussion about methods and prospects for sustainable agriculture This will include some discussion about the possibilities/hazards associated with the use of genetically-engineered organisms in agriculture. For each topic in the course, we discuss prospects for sustainability and alternatives. I don't want you to leave the course despairing, because for all of the problems that we talk about there are potential solutions.

(3) Selected air quality issues. We will address general considerations related to air pollutants and their impacts on ecosystems, and will then focus on one pollutant that has regional effects on natural and agroecosystems, as well as on human health; tropospheric ozone.

(4) Global climate change and stratospheric ozone depletion. Here we will focus on chemicals in the air that are likely to have (or already have) truly global impacts. We will discuss the increasing atmospheric burden of CO2 and other radiatively active gases and their likely consequences for the global climate system (and consequences of changes in that for natural and human systems). We will also look at gases that are depleting the protective ozone layer in the stratosphere and at likely consequences of that depletion. Both are, truly global issues, as we'll see, and both are connected to expanding human population and agricultural growth in a variety of ways. In fact, we will see that virtually everything we discuss has implications for all of the other topics we deal with.


If we have time, we'll also talk about the following two topics. I have not had time for these topics in any of the last several years, so it is unlikely that we will get to them this year. NOTES ON THE TOPICS BELOW HAVE NOT BEEN UPDATED FOR SEVERAL YEARS!!!

(5) Gobal patterns in forest cover and consequences. We will take a relatively quick look at what is happening to forest resources, both globally and locally, and the implications of these trends.

(6) Threats to biological diversity, with a Pacific Northwest focus. A logical follow-on to the discussion about patterns in forestation, is to talk about consequences of habitat loss for the biological diversity of regions or of the earth. We will focus on examples taken from the Packific Northwestern U.S., again looking at prospects for a hopeful future

(Click on ">>" in the box at the bottom of this page to continue scrolling through these notes (for information on ecosystems and levels of causation in environmental science). To return to the master Table of Contents, click the box labeled "CONTENTS" at the bottom of this page. For general information on how to navigate within and among these documents, click "Navigate," here.)

Page maintained by Patricia Muir at Oregon State University. Last updated Oct. 15, 2012.