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
Gases to current warming
(does not include water vapor) The major (99%) constituents of the atmosphere, oxygen and nitrogen,
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This test prep was uploaded on 03/20/2014 for the course BIOLOGY 171 taught by Professor Hunter during the Fall '09 term at University of Michigan.
- Fall '09