California State University Long Beach 

Complexity of modern climatic change

• Global warming / global cooling
• When we look closely:
• Does anything change globally?
• Do all changes have a global effect?
• The truth is that any change may weave a complex web

• Irregular multi-year (3-7?) cycle of oceanographic & climatic change
• Typically last 14-22 months, but quite variable
• Centered in Pacific, but global effects
• Web of triggering events (El Niño)
• Westward shift of atmospheric high pressure cells
• Weakened trade winds
• Slowed westward flow of equatorial surface water
• Warm pool relaxes back to the east
• Storms and rain shift from Indonesia eastward
• Normal years referred to as "La Niña"

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Climatic & ecologic repercussions in the Pacific

• Decreased upwelling off Peru
• Catastrophic reduced fisheries
• Torrential rains along west coast of North & South America (California)
• Floods, mudslides, crop damage
• Drought and fires in Australia, Indonesia, Micronesia

Teleconnections (somewhat predictable)

• Equatorial air temperature and pressure disrupts the jet stream
• Simultaneous warm pool shift in Indian Ocean
• Drought in India, Australia, central North America, Caribbean, & Africa
• Fires and starvation

• Recent El Niño episodes
• 1977-1978, 1982-83, 1986-87, 1991-92, 1993-94 Mississippi floods), 1994-1996 (some consider 1990-1996 the longest single El Niño
• 1982-1983: the worst El Niño of the century
• Encephalitis along the east coast (mosquitoes)
• Bubonic plague in New Mexico (fleas)
• Shark attacks off Oregon (warm water)
• Drought in Spain & N. Africa
• Changing frequency of El Niños
• During the Little Ice Age
• Every 7-10 years
• This century
• Every 3-5 years
• Past 20 years
• Six episodes
• Why?
Global warming????

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