DANCEST 805 Lecture Notes - Lecture 27: Nonpoint Source Pollution, Lethal Dose, Ozone Depletion
Document Summary
Global change is a planetary-scale change in the earth system. Global change affects population, climate, economy, resource use, energy development, transport, communication, land use, urbanization, globalisation, etc. In the past, the main causes included: solar variation, plate tectonics, volcanism, proliferation and abatement of life, meteorite impact, resource depletion and changes in earths orbit. However, now the overwhelming driver of global change is the growing human population. We have a high demand for energy, food, goods, services and information and disposal of waste products. It"s caused climate change, species extinction, desertification and ocean acidification, and ozone depletion and pollution. It is the introduction of contaminants into natural environment, causing adverse change. It is in the form of chemical substances or energy, they can be foreign or naturally occurring and are classed as point or non-point. A point source is a single identifiable source of pollution. A non-point source is a used to describe pollution resulting from many diffuse sources.
