Climate change at other scales

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Climate change at other scales

• The El Nino Southern Oscillation

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Last Lesson

• Specifically looked at Micro-Climates
• 4 types- Upland, Coastal, Forest and Urban
• Urban Heat Islands (handout)
• Atmospheric pollution in Urban areas
• Presentations

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Well done!!
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El Niño / La Niña

• El Niño Southern Oscillation will often be
  referred to as ENSO in your exam
• After the seasons, El Niño and La Niña are the
  single largest cause of year-to-year climate
  variability on the Earth
• The devastating El Niño event of 1997/98 ranks as
  the second strongest in the past century, causing
  over 2,000 deaths and leaving a global damage
  bill of around 20 billion
• El Niño literally means the child and was named
  by Peruvian fishermen who noticed around
  Christmas time coastal waters got warmer and fish
  became more scarce
• La Niña means the female child

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What is El Niño / La Niña?

• El Niño is a current of warm water which occurs
  in the Pacific Ocean every 3 to 7 years
• An El Niño event may last for many months
  resulting in significant change in weather
  patterns and significant economic consequences
  worldwide
• During the past forty years, ten of these major
  El Niño events have been recorded, the worst of
  which occurred in 1997-1998
• Some of the El Niño events have persisted more
  than one year

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What causes El Niño?

• In truth, they are still yet to be fully
  understood
• The major factor is the strength of the
  prevailing trade winds that blow from east to
  west across the equatorial Pacific
• In the tropical Pacific Ocean, trade winds
  generally drive the surface waters westward
• As a result, the surface water becomes warmer
  going westward
• El Niño is observed when the easterly trade winds
  weaken, allowing warmer waters of the western
  Pacific to move eastward and eventually reach the
  South American Coast

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What are the effects of El Niño?

• The cool nutrient-rich seawater normally found
  along the coast of Peru is replaced by warmer
  water depleted of nutrients, resulting in a
  dramatic reduction in marine fish and plant life
• In some parts of the world, El Niño causes heavy
  rains and flooding. In other parts of the world,
  drought and starvation occur as a result of El
  Niño. In the ocean, fish migrations and coral
  reef ecosystems are disrupted due to the ocean
  temperature changes caused by El Niño
• Some events attributed to the last El Niño
  include floods and landslides in Ecuador which
  resulted in death and property damage The
  Atacama Desert, which is known for its arid
  climate, received a greater amount of rainfall
  than normal Santiago in Chile experienced severe
  flooding as a result of heavy rainfall
• The effects of El Niño are not restricted to
  South America however. Also attributed to El
  Niño, drought caused widespread hunger in Papua
  New Guinea water shortages were reported in Java
  and drier conditions than usual were experienced
  south eastern Africa. This reduced crop yields
  and resulted in starvation. In parts of India,
  the monsoons were weaker than normal, again
  affecting crop growth

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Other Effects

• The El Niño in 1982-83 also caused much damage.
  In Australia, it caused massive bush fires and
  widespread drought
• In the sub-Saharan countries, it caused one of
  the worst periods of drought, with the monsoons
  failing again in India
• Approximately two thousand lives were lost as a
  result of this El Niño, with damages estimated to
  have cost over 8 billion

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What is La Niña?

• In contrast to El Niño, La Niña refers to an
  anomaly of unusually cold sea surface
  temperatures found in the eastern tropical
  Pacific
• La Niña occurs roughly half as often as El Niño
• La Niña also affects the oceans and global
  climatic patterns although not usually on the
  same scale as El Niño

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Summary
During an El Niño
El Niño events typically bring heavy, drenching
rain to South America, while Indonesia
experiences drought conditions
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Summary
During a La Niña
During La Niña the opposite occurs to El Niño.
Heavy rain over Northern Australia and Indonesia,
and drought in South America
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The Impacts of El Niño

• (ENSO)

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The Impacts of El Niño

• The ENSO affects the whole worlds climate,
  therefore has a massive global impact
• Surprisingly, not all these effects are bad-
  during an El Niño, the Atlantic becomes slightly
  cooler, so the Hurricane season over the
  Caribbean and USA is less dramatic
• Also, the rain in California helps to clear the
  smog / pollution in Los Angeles

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Task (to be completed for HW)

• Using pages 82 and 83
• Make notes from page 82 83. Try to show the
  impacts on People, the Environment the Economy
• Answer Questions 1, 2 3
• You will need a blank outline map for Q2
• Questions will be in next week