We are still today in that transition from rural

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Unformatted text preview: ciety characterized by explosive population growth and by urbanization. We are still today in that transition from rural agrarian to urban-industrial society. How are fossil fuels formed? Not all detritus is successfully recycled by decomposers/detritivores. They are especially inefficient in environments with low oxygen levels, e.g., bogs and swamps, where accumulated detritus may become buried and fossilized. Iron Age Danish Bog Body Our modern lifestyles are predominantly fueled by the preserved detritus of long-extinct ecosystems Many of our primary coal deposits date from the Carboniferous Period (360-286 million years ago) when incomplete decomposition of dead plant material in extensive swampy forests lead to their preservation and burial. Pressure and heat over millions of years slowly transformed this material into coal. In different geological conditions, the dead biomass is transformed instead into oil and/or natural gas. All three formats retain much of the chemical energy present in the original detritus and this is still available (millions of years later) for us to exploit. Greenhouse Effect Sun’s rays penetrate atmosphere. ozone benzene H2O CO2 CO2 methane methane H2O N2O CFCs N2O Earth’s surface radiates heat. Greenhouse gases absorb some heat and re ­ emit it back toward Earth. Increased [greenhouse gas] trap more heat near Earth’s surface. Carbon dioxide is one of several greenhouse gases—gases that trap heat radiated from Earth and keep it from being lost to space. Increases in the amounts of greenhouse gases have the poten<al to warm Earth’s climate by increasing the atmosphere’s heat ­trapping poten<al. Some Greenhouse Gas is Good Natural Greenhouse Effect: Greenhouse gases naturally blanket the Earth and keep it ~ 330 C (60 0F) warmer than it would be without these gases in the atmosphere. Greenhouse gases are vital to making our planet habitable. GHGs: water vapor (most impt) CO2, methane others, too, but those are less important Relative Importance of Human-produced Greenhouse Gases to current warming (does not include water vapor) The major (99%) constituents of the atmosphere, oxygen and nitrogen, are not...
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