Environmental Pollution Lecture 1 - Jan. 14 Outline: ❖Humans are massively changing the Earth ❖Why does pollution happen? ❖Global Pollution and Global Env. Health ❖Root Causes ❖Our Actions Have Consequences Humans are massively changing the Earth -Btwn ⅓ and ½ of the Earth’s land surface has been transformed by human action -The carbon dioxide concentration in the atmosphere has increased by nearly 30%since the beginning of the Industrial Revolution -More than half of all accessible surface freshwater is put to use by humanity -More atmospheric nitrogen is now fixed by humanity than by all natural terrestrial sources combined -ABout ¼ of the bird species on Earth have been driven to extinction Biosphere 2: The Experiment -Objectives:to test if and how people could live and work in a closed biosphere, while carrying out scientific experiments and to explore the possible use of closed biospheres in space colonization -Key Issues:O₂ levels began falling at a steady pace of 0.5% per month. This trend continued to the point where the atmosphere inside resembled that of a community at an elevation of over 1200m -Atmospheric C0₂ spiked erratically, while nitrous oxide (N₂0) rose to levels that could impair brain fxn -Water became polluted, and several plant and animal species became extinct A Pessimistic Conclusion -Earth is a closed systemtoo, a larger version of Biosphere 2 -Closed system : only energy is naturally transferred outside the atmosphere. No mass enters or exits the earth.
Ten Lessons from Biosphere 2 1. Ecology can be a science a. First time ecology had controllable variables with complexity similar to chemistry and physics, opening up future studies 2. Coral reefs are salvageable a. Marine biologist Gaie Allingoversaw the largest artificial reef and learned how to manage ecologically stressed reefs in nature 3. Complexity is no obstacle a. Scientists who helped build the Biosphere thought the experiment was crazy becuz of sheer complexity, it was found that even with complications (bees dying out) the system balanced itself 4. Massive spacecraft WILL hold their air a. It was the largest sealed structure made but overall air leakage rate was less than 10% per year, lesson learned was that concrete sucks up CO ₂, which is not good 5. Long space flights won’t drive you nuts a. First time people have lived in enclosed spaces for such a long time and with this kind of physical separation. There was tension but no violence or serious altercations.