Climate Change + The Oceans

• Four types of coral reef


  • Fringing
  • Barrier
  • Atoll
  • Patch
• Patch Reef is not made from volcanic subsidence
• Environmental bioassays


  Study to test for pollution on a species
• 80% of marine debris are plastic
• Half (53%) of oil in the ocean is originating from human activity
• Two ways to clean up oil spills

  • Dispersants
  • Bioremediation
• Weather


  Describes conditions of the atmosphere at a given time and place
• Climate


  The long term average of weather
• The Earth's Climate System is made up of the atmosphere, hydrosphere, geosphere, biosphere, and cryosphere which are all interconnected
• Climate change


  Recorded as a rise in global temperatures over the last >100 years (global warming)
• 0.1°C increase per decade since 1900
• 0.15°C increase per decade in the last 25 years
• 1.0°C total increase since 1900
• Last glacial maximum (21,000 years ago) had global average temperatures ~4-5°C colder than today
• Weather is not the same as climate
• Human-induced emissions of greenhouse gases are causing the recent rise in global temperature since the Industrial Revolution
• Greenhouse gas


  Gases whose chemical structure allows them to have the capacity to trap heat
• Greenhouse effect


  The heating of the Earth's atmosphere that results from the absorption of infrared radiation (heat) from the Earth's surface by greenhouse gases in the atmosphere
• Greenhouse gases


  • Water vapor
  • Carbon dioxide (CO2)
  • Methane (CH4)
  • Nitrous oxide (N2O)
  • Ozone (O3)
  • Chlorofluorocarbons (CFCs)
• Water vapor contributes between 36-66% of the greenhouse effect, with clouds 75%
• Water vapor in atmosphere not changing significantly with time - not anthropogenic - NOT the cause of climate change
• Carbon dioxide (CO2) provides the greatest contribution of any greenhouse gas to the increase greenhouse effect on Earth
• In 2016 the CO2 in the atmosphere passed 400 ppm and is increasing at 2 ppm per year
• Methane (CH4) is the second most abundant greenhouse gas
• Nitrous oxide (N2O), ozone (O3), and chlorofluorocarbons (CFCs) are other greenhouse gases with more heat absorption capacity than CO2
• CO2 has the greatest relative contribution to the increasing greenhouse effect
• Ice cores from Antarctica preserve ancient atmosphere in tiny bubbles formed during snow compaction in glaciers
• Paleoclimatologists - scientists who analyze data and develop models of past climate
• Proxy data


  Indirect measures of Earth's past conditions by natural recorders such as tree rings, sea floor sediments, trapped air bubbles in sea ice, etc.
• Milankovitch cycles


  Natural changes in the Earth's orbit that cause the Earth to favor glacial or interglacial periods
• Milankovitch cycles


  • Variations in Earth's orbit (eccentricity): ~100,000 year cycle
  • Variations in the tilt of Earth's axis (obliquity): ~41,000 year cycle
  • Variations in direction the Earth points (wobble, precession): ~23,000 year cycle
• We are in a "cooling" phase of historical glacial/interglacial cycles, not a warming phase
• Volcanoes do release CO2, but humans have released at least 130x as much CO2 in the same time period
• No record of extensive volcanism to produce the concentrations we are seeing over the last ~100 years
• Atmospheric CO2 is rising - we can measure it! Keeling curve
• Radioactivity of CO2 in the atmosphere is decreasing - the new CO2 in the atmosphere is OLD (>25,000 y)
• Decreasing 13C/12C isotope ratio tells us there is a greater influence from plants (which have more 12C)
• Weather


  Short term
• Climate


  Long term
• Global temperature has increased by 1 degree Celsius since 1900