Climate Change

• What is climate change?

  Climate change is the long-term shift in the planet's weather patterns or average temperatures
• Evidence for climate change

  -average global temps

  -Ice cores

  -Shrinking glaciers

  -Seasonal glaciers

  -Rising sea levels
• What is the quaternary period


  The most recent geological time period, spanning from about 2.6 million years ago to the present day where temperatures have fluctuated a great deal
• 4 effects of global climate change

  -many of the worlds glaciers and ice caps are sinking

  -low lying Pacific islands (Tuvalu and Maldives) are under threat from rising sea levels

  -sea levels may rise by 1m by 2100 flooding agricultural land ( Bangladesh, Vietnam, India)

  -arctic sea ice is less extensive than in the past
• explain rising sea levels


  The average global sea levels has risen between 10 and 20cm in the past 100 years
• How do sea levels rise

  When temperatures rise, freshwater ice melts resulting in more water in seas

  When ocean water warms it expands in volume- thermal expansion
• Explain seasonal changes


  The timing of natural seasonal activities such as tree flowering and bird migration is advancing
• Example of a seasonal change


  A study showed that bird nesting in mid 1900s discovered that 65 species nested on average of 9days earlier
• Explain shrinking glaciers and melting ice

  Glaciers throughout the world are shrinking and retreating
• Example of shrinking glaciers and melting ice (arctic sea ice)

  Arctic sea ice has thinned by 65% since 1975 and in 2014 it's extent was at an all time low
• What is happening to the arctic sea ice

  Arctic sea ice is less extensive than in the past affecting wildlife such as polar bears. This may provide opportunities for ships to use the North West Passage in the future
• What are ice cores


  Cylinders of ice drilled out of an ice sheet or glacier
• How can scientists use ice cores to tell them what the global temperatures were like in the past

  Scientists can study the oxygen in ocean sediments and water molecules in ice to calculate the temperature
• What are the three main natural causes of climate change

  orbital changes, solar activity, volcanic activity
• What are orbital changes also called

  Milankovitch cycles
• What is eccentricity?

  Varies from a circular to elliptical orbit which happens every 90,000-100,000 years
• What is axial tilt?

  The tilt of the earth axis moves back and forth between 21.5 and 24.5 every 41,000 years
• What is a precession of the Earth?


  A slow change or wobble in the orientation of the Earth axis over a period of 26,000 years
• What are the short term impacts of volcanic activity

  Block out sun, reducing temperatures on Earth
• What are the long term impacts of volcanic activity

  Sulphur dioxide is released from volcano which converts to sulphuric acid which acts like a mirrors reflecting radiation from sun which over many years will also reduce temperatures
• Example of volcanic activity (1991)


  Mt. Pinatubo, 1991

  Earths surface cooled for 3years after eruption by as much as 1.3degree
• Example of volcanic activity (1816)


  Mt Tambora, Indonesia 1816

  Most powerful eruption in the world for 1600years

  Average temps fell by 0.4-0.7degrees
• Impacts of volcanic activity

  -radiation from suns is reflected so doesn't reach earth

  -global temperatures fall

  -crop failure therefore famines, health issues from ash, distress etc

  -
• What is the natural green house effect


  The greenhouse effect keeps the Earth naturally warm enough to support life
• What is the difference between enhanced greenhouse effect and natural greenhouse effect

  The enhanced greenhouse effect is due to human activities which has increased the amounts of greenhouse gases but the natural,greenhouse effect keeps the earth naturally warm
• How much carbon dioxide accounts for the enhanced green house effect

  60%
• Where does carbon dioxide get released

  Car exhausts

  Deforestation

  Burning wood

  Burning fossil fuels
• How much methane accounts for the enhanced greenhouse effect


  20%
• How is methane released?

  Farm livestock

  Rice farming

  Burning biomass for energy

  Decaying organic matter in landfill sites and compost sites
• How effective is nitrous oxide in capturing heat then co2

  Very small concentrations are up to 300times more effective
• How does nitrous oxide get released

  Car exhausts

  Sewage treatment

  Agricultural fertilisers

  Power stations
• What are the 4ways climate change can be managed

  Alternative energy sources

  Carbon capture and storage

  Planting trees

  International agreements
• What is a sunspot?


  A dark patch on the surface of the sun which produces heat
• How do sunspots effect temperatures on Earth

  The amount of radiation emitted by the sun fluctuates. High levels of radiation easily to an increase in earths temperatures
• The burning of fossil fuels accounts for how much of the carbon dioxide emissions


  87%
• What are the alternative energy sources

  Wind, water, geothermal, nuclear, biomass, solar, tides
• Explain the process of carbon capture and storage

  The process of 'carbon capture and storage' is when carbon molecules are captured, compressed, piped and injected as a liquid to a well underground to be stored in a suitable geological reservoir
• How do trees remove Co2 from the atmosphere

  photosynthesis
• How does planting trees reduce climate change?

  Trees release moisture into the atmosphere which produces more cloud, reducing solar radiation producing a cooling effect

  Trees also absorb Co2
• First international agreement

  Kyoto Protocol (2005)

  Countries agreed to reduce carbon emissions by 5.2% by 2012

  USA and Australia didn't sign- two of the biggest emitters of carbon which meant the agreement wasn't very helpful