The Greeks weren't far off, Earth, Air, Fire and Water are pretty important, and interesting too. Why they are what they are, how they change, and how they influence us form the basic questions of Envionmental Chemistry.
I've got my own text in draft form which I will try to get posted as soon as possible - but don't hold your breath! Meanwhile, I'll try to store good links here as I come across them on the web (or in my old bookmark files).
Anyone who believes in a kind and gentle natue should look at the sun. Sure, it keeps us alive, but that wasn't really it's first choice. Not only does it emit light energy just energetic enough to coerce water and carbon dioxide into forming higher energy and temporarily stable molecules that we call food and oxygen, but it also blasts out plenty of higher energy UV light that can blast apart the bonds that keep us delicate life-forms living. Good thing that the same UV energy can change some of that oxygen into UV absorbing ozone, and that the pathways making and destroying ozone balance with just 'the right' amount left up there (only a few millimeters thick if brought down here to the surface) to shield us delicate creatures. Seems kind of important that we understand the processes that make and destroy the stuff - so we don't go destroying (or increasing) our cosmic sunscreen.
Tropospheric Ozone
Global Change
The Ultimate Tree-Ring Web Pages
Global Tropospheric Experiment (GTE) Home PageThumbnails # 13 - 22- Effects of Past Global Change on Life
SCIENTIFIC AND TECHNICAL CAPABILITIES (Oak Ridge)
THE GLOBAL CHANGE MASTER DIRECTORY
Lamont-Doherty Earth Observatory
Carbon Dioxide Information Analysis Center (CDIAC)
U.S. Global Change Data and Information System (GCDIS)
USGS- Release of Declassified inventory
Acid Deposition
Eutrophication & Watersheds
Metals
OrganicsEPA's Integrated Risk Information System (IRIS) - Home Page
THESE NEED TO BE REENTERED AS INDIVIDUAL LINKS