ENV 101 Lecture Notes - Lecture 11: Oil Sands, Fly Ash, Arctic National Wildlife Refuge
Document Summary
Fossil fuels combustible deposits found in the earth"s crust (land and ocean: composed of the remnants (fossils) of prehistoric organisms (plants and animals) that existed millions of years ago, includes coal, oil (petroleum) and natural gas. Supply over 80% of energy used in north america!! Are a non-renewable resource: fossil fuels are created too slowly to replace the reserves we use. Impact of fossil fuels on the carbon cycle. Plants use co2 make their biomass cellular respiration, decomposition of dead co2 released back to atmosphere. Combustion (fossil fuels, wood, etc) also puts co2 back into the atmosphere. The problem is in the rate of return. Carbon that took millions of years to accumulate is being released (as co2) in about 200 years. Equilibrium of co2 in atmosphere, oceans, in organic matter has dramatically shifted. 300 million years ago, climate was mild, vast swamps covered much of land. Dead plant material decayed slowly in the swamp environment.
