natural causes

• orbital changes - Miilankovitch cycles

  • 3 cyclical changes in the earth's orbit and tilt that causes climate fluctuations
  • every 100,000 years the orbit changes from spherical (glacial period) to elliptical (interglacial/ warmer period)
  • warmer periods are associated with higher carbon in the atmosphere
  • every 42,000 years the earth's tilt increases causing increased temperatures in summer so higher carbon in the atmosphere
• volcanic eruptions 


  • they release co2 and aerosols
  • aerosols scatter incoming solar radiation causing a slight cooling effect as sunlight is blocked which lasts for 1-2 years
• variation in solar radiation

  • total amount of radiation varies slightly due to the number of sunspots which are dark areas on the sun's surface
  • a sunspot develops when a intense magnetic field weakens the flow of gases that transports heat energy from the sun's interior
  • sunspots appear darker because their temperature is lower than the surrounding area
  • every 11 years the number of sunspots changes from a maximum number to a minimum number
  • sunspots suppress heat so when there a more sunspots there is more radiation emitted
  • more sunspots may contribute to a warmer global climate
• movement of crustal plates

  • as tectonic plates move over geological timescales, landmasses are carried along to different positions and altitudes
  • global circulation patterns of air, ocean and continent climates are affected
  • landmasses warm faster than oceans due to the high specific heat capacity of the oceans
• El Niño 


  • every 3 years the south east trade winds weaken allowing the warm water to flow further eastward towards South America causing it to be warmer and experience wetter weather
  • the east of the Pacific Ocean experiences cold and dry weather due to high pressure and cold ocean
  • low pressure forms over the warm ocean creating heavy rainfall
• La Nina 


  • occurs every 3-5 years when strong trade winds blowing from east to west decrease surface sea temperatures in the eastern Pacific
  • Strong trade winds warm and moisten as they travel west over the Pacific
  • Warm, moist air rises in the western Pacific, forming low pressure
  • As the warm, moist air rises into the atmosphere, it cools and condenses, increasing precipitation
• Asteroids - Mexican Meteor Strike

  • temporarily heat the earth's surface to several hundred degrees due to the friction of airborne particles ejected into orbit
  • temperatures would drop for several months due to limited sunlight
  • melting rocks at the impact site would release carbon
• Wildfires


  • large quantities of carbon from biomass is transferred to the atmosphere
  • loss of vegetation decreases photosynthesis so more carbon is lost to the atmosphere
  • fires can encourages new plant growth which takes in carbon during photosynthesis