Wrap Up

Review of the main topics and ideas you encountered in Unit 12.

Fuelish

• Plants turn carbon dioxide, water and sun’s energy into more plants and oxygen.
• Other life forms “burn” plant with oxygen to get that energy.
• If buried without oxygen, plant isn't burned, and heating makes fossil fuel.
• Woody plants-->peat (in sediment; Bear Meadows) -->lignite (in sedimentary rock)-->bituminous (in harder sedimentary rock, western PA) --> anthracite (in metamorphic rock, eastern PA).
• Algae-->gas from bacteria (Bear Meadows)-->oil (with gas) (western PA)-->gas (eastern PA) (float up and escape to be burned unless trapped by geology).

Take It to the Limit

• Fossil fuels are NOT infinite:
  • nature really is efficient at recycling;
  • oil & coal companies good, found the easy stuff;
  • not a lot set aside (ANWR oil estimated to equal only just over 2 years of US imports).
• World oil production peak likely in next decades
  • at vaguely recognizable prices and current demand, probably close to a century of oil and gas, a few centuries of coal;
  • but demand rising rapidly, so less time.

You’re in the Greenhouse Now

• some gases let visible light through (sun) but partly block infrared (return from Earth);
• makes planet warmer than otherwise, so we “glow” brighter to force energy past the gases;
• we are increasing these gases (esp. carbon dioxide) a lot, and they will stay up for centuries, millennia or longer.

With High Confidence

• Our greenhouse gases will warm world, amplified by feedbacks such as melting of reflective ice increasing warming (maybe 16^oF over centuries if we really burn fossil fuels, vs. barely-noticeable 1^oF so far);
• positive and negative impacts on us, but mostly negative for warming more than a few degrees:
  • sea-level rise from ice melt, expanding ocean;
  • summertime drying of grain belts;
  • not-nice tropical heat.

Making Money

• We have to switch from fossil fuels; will we do so before or after we change the world?
• Reasonable estimates say switch needs few decades of serious research and 1% of economy:
  • this is in line with other clean-up costs now;
  • this is something like $400 billion per year now.
• Not a lot of scientific disagreement on these points,
• but much political, social, economic disagreement (which is completely expected, and in line with previous environmental issues).

Lions and Tigers and Bears?

• Why save biodiversity--medicines, other useful things from living types; more-diverse ecosystems produce more; living types “canaries in coal mine” to warn us of trouble; ethics
• Early and modern humans hard on biodiversity--next mass extinction?
• Smaller islands have fewer species (easier to eliminate smaller population), so isolating patches of wilderness in separate national parks will lose species in those parks.
• Climate change will complicate, forcing migration when there may not be migration pathways.