Notes

• Natural reasons for Climate Change

  Asteroid

  Volcanoes

  Breaking up of Pangea

  Orbital Cycles
• How do Asteroids affect climate change

  The Chicxulub Asteroid hit the Earth at a shallow angle

  The Earth got colder as the ash covered the sun

  plants that perform photosynthesis (absorbs CO2 so it doesnt stay in the atmosphere) die

  more greenhouse gases are in the atmosphere making the Earth warmer due to the greenhouse effect
• How do volcanoes affect climate change?

  CO2 gas rises to the surface through steam vents from water being heated by magma

  when volcanoes erupt CO2 is released

  even when volcanoes are not erupting CO2 is being released

  with large eruptions the ash covers the sun creating a nuclear winter
• How does the breaking up Pangea affect climate change?

  open or close ocean currents changes temperature

  the warm seas travel around the planet
• How does Orbital cycles (Milankovitch) affect climate change?

  cycles affect the amount of sunlight / energy the Earth absorbs

  the cycles repeats between 20000, 40000 and 100000
• Positive Feedback


  amplification

  higher temperature = ice melting, decreases albedo effect which leads to higher temperature (repeat)
• Negative feedback


  nullifying

  higher temperature = more evaporation, rainfall, increase in plants and vegetation, more photosynthesis is occurring, decrease in temperature due to the lower number of greenhouse gases in the atmosphere
• Climate Change Timeline

  • 2 million years ago there was a short period of ice on Earth
  • interglacial periods (glacial retreat) and glacial periods (glacial advances) fluctuates
  • current interglacial period is called the Holocene, started 11,000 years ago
  • 25,000 years ago was the last glacial maximum
  • period of time 2.6 million years ago to now is called the quaternary
• Evidence of Climate Change

  ice core

  cave painting

  satellite

  fossil record
• How are ice cores evidence of climate change?


  provides climate and ice

  gives dynamics infomation over many years in very high resolution

  gets infomation by using CO2 and O2 isotope levels
• What are the limits in ice core data?

  melting of the ice can cause difficulty in dating accurately

  overall results may not be reliable
• How are cave paintings evidence of climate change?

  direct measurement of previous environments

  cheap as they can be found around the world
• What are the limits to cave paintings to use as evidence of climate change?

  can be inaccurate and therefore unreliable

  cave paintings may have not painted the actual climate / weather of their time
• How are satellites, ocean buoys and weather balloons evidence for climate change

  they can take live pictures with direct measurements

  global area is covered

  shows change of temperature

  reliable and accurate
• What are the limits to satellites, ocean buoys and weather balloons?

  expensive

  modern and therfore no historical infomation

  information is collected over short time scales
• How are fossil records evidence of climate change?

  it contains carbon which can be dated - carbon dating

  very long time scale
• What are the limits to fossil records?

  there may be missing links

  destruction can cause results to be inaccurate and therfore unreliable