climate change

• what is the quaternary period?

  the period of geological time from about 2.6 million years ago
• What is climate change?

  a long-term change in the earth's average temp and weather patterns
• what long-term climate change has taken place?

  on 100,000 year cycles, the earth has fluctuated (changed) between glacial (cold) and interglacial (warmer) periods
• what evidence is there for long-term climate change?

  oxygen and carbon dioxide trapped in air bubbles in ice cores. after analysis, scientists can work out what temps would have been like
• what short- term climate has taken place?

  since 1880 the average global temp has risen by 1 degrees celcius
• what is the evidence for short-term climate change?

  1. thermometer readings

  2. seasonal changes- bird migration patterns are shifting

  3. rising sea levels- average global sea level had risen between 10-20 cm in the past 100 years

  4. ice melt- artic ice is at its lowest
• why are sea levels rising?

  1. the water is getting warmer and so expands= thermal expansion

  2. the ice sheets and glaciers on land are melting and adding water to the oceans
• what are the natural causes of climate change?

  1. orbital changes

  2. sunspots

  3. volcanoes
• How do orbital changes cause climate change?

  eccentricity- the orbit chamges shape form a circle to an oval on a 100,000 year cycle

  precession- the earth wobbles on its axis; affects the seasons and day lengths

  axial tilt- the earth's axis is tilted on the angle; affects the intensity of the seasons- on a 41,000 year cycle
• Milankovitch cycles

  eccentricity, precession, axial tilt
• how do sunspots cause climate change?

  solar activity- sunspots, which are a sign of solar flares, increase insolation and this leads to increases in temp over a short term
• how do volcanoes cause climate change?

  short term: volcanoes erupt ash which blocks the sun and cools the temp

  long term: sulphur dioxide is also emitted and turns into sulphuric acid which reflects radiation from the sun
• What kind of radiation does the sun emit?

  shortwave radiation
• What kind of radiation does the earth emit?

  longwave radiation
• What is the natural greenhouse effect?

  -The atmosphere most short-wave to pass through

  -The Earth's surface is absorbed and warmed

  -The earth emits long-wave radiation

  -Long-wave radiation is mostly absorbed and reemitted into the atmosphere by the greenhouse gas layer.
• What is the enhanced greenhouse effect?

  Humans are adding to the greenhouse gas layer, which is increasing the amount of long-wave radiation absorbed and reemitted into the atmosphere. This iswarmingthe atmosphere more
• What are greenhouse gases?

  Gases that absorb long-wave radiation

  Examples: CO2, Methane
• What are human sources of greenhouse gases?

  Fossil fuels: Burning fossil fuels releases CO2. They are used in transport, building, and producing energy.-60% of greenhouse gases

  Agriculture: Microbes in flooded rice fields produce methane-Cows produce methane in digestion 20% of greenhouse gases.

  Deforestation: Trees are cut down for land for farming, logging and expanding urban areas-Less carbon can be absorbed by trees, increasing the amount of carbon in the atmosphere-When trees are burnt, carbon is released
• What are the effects of climate change?

  • Social-Drought will affect food supply in desert areas-Malaria increases as more places are hot enough for the mosquitoes to thrive
  • Economic-East Asian Fishing industry declines as the sea is less habitable-Flood risk increases, causing huge property damage to Bangladesh and London
  • Environmental-Low lying islands e.g -Maldives will disappear due to sea level rise-Coral reefs will lose biodiversity
• What is mitigation?


  Action taken to reduce or eliminate the long-term risk to human life and property

  Reducing the amount of carbon in the atmosphere
• What strategies mitigate against climate change?

  1. Alternative Energy production

  Other ways of producing energy e.g solar, wind, tidal, hydroelectric

  2. Carbon Capture

  technology is used to take carbon from the power station and is stored in the ground, in coal or in old coal fields

  3. Planting trees (afforestation)

  International agreements

  4. When countries work together
• How does alternative energy production mitigate against climate change?

  Most renewable energy sources do not emit any greenhouse gases, and so can produce energy without enhancing the greenhouse effect.
• How does carbon capture mitigate against climate change?

  Carbon dioxide does not enter the atmosphere, and so the greenhouse effect is not enhanced, even though fossil fuels are still being used
• How does planting trees mitigate against climate change?

  Trees absorb carbon dioxide for photosynthesis and so there is less carbon dioxide in the atmosphere to cause global warming.
• How do international agreements mitigate against climate change?

  At the 2015 Paris climate conference all countries agreed to keep global temperatures below 2 degrees.
• What is adaptation?


  Actions taken to adjust to natural events

  Learning to live with climate change
• What strategies are there to adapt to climate change?

  1. Change in agricultural systems

  2. Changing farms

  3. Managing water supply

  4. Reducing risk from rising sea levels
• How does changing agricultural systems adapt to climate change?

  Why?Increased drought affecting outputStrategies?1. Drought resistant crops.Using different seeds which are better at coping with less water2. Drip irrigationWater is dripped directly on, using less water to water crops.
• How does managing water supply adapt to climate change?

  Why?Water use is increasing but supplies are less reliableStrategies?1. Tap aeratorsMixing air into the water so it is the same flow but less water is being used2. Water buttsStoring rainwater and reusing it3. Water transfer schemesPumping water from areas of surplus (too much) to areas of deficit (too little)
• How does reducing risk from rising sea levels adapt to climate change?

  Why?20 cm rise since 1880. Islands like the Maldives are vulnerableStrategies?Building homes on stiltsCoastal defences like sea walls to keep flood water out