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Wicked Problems. Global Climate Change. Central Case: Rising seas may flood the Maldives. Central Case: Rising seas may flood the Maldives. Central Case: Rising seas may flood the Maldives. Our dynamic climate. Climate : an area’s long-term atmospheric conditions
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Wicked Problems Global Climate Change
Our dynamic climate • Climate: an area’s long-term atmospheric conditions • Temperature, moisture content, wind, precipitation, etc. • Influences everything around us • Weather: conditions at localized sites over hours or days • Global climate change: describes trends and variations in Earth’s climate • Temperature, precipitation, storm frequency • Global warming: an increase in Earth’s average temperature • Earth’s climate has varied naturally through time. • The rapid climatic changes taking place now are due to human activity: fossil fuels, combustion, and deforestation.
What changes climate? • Changes in: • Sun’s output • Earth’s orbit • Drifting continents • Volcanic eruptions • Greenhouse gases
The E-M Spectrum The Sun’s Energy Warms the Earth
Fate of Solar Radiation Reaching the Earth reflection Clouds (20%) snow and ice + the earth’s surface (20%) atmospheric dust (6%)
Fate of Solar Radiation Reaching the Earth absorption Oceans + Land (51%) Atmosphere (16%) Clouds (3%) Plant photosynthesis (<1%)
Fate of Solar Radiation Reaching the Earth Radiation Radiated to space from clouds and atmosphere (64%) Radiated directly to space from Earth (6%)
Greenhouse Gases Carbon Dioxide Methane Nitrous Oxide Water Vapor Ozone
Atmospheric CO2 (ppm) Temperature Change (oF) Thousands of Years Before Present
Atmospheric CO2 & Surface Temperature Trends Atmospheric CO2 (ppm) Temperature Temperature Change (oF) Carbon Dioxide Year
Predicted changes with increased greenhouse warming • Sea level rise • Increased plant primary productivity • Shifts in the distribution of plants and animals • Water contamination and outbreaks of water-borne diseases • Increased storm severity • Potential melting or enlargement of polar ice caps • Changes to patterns of rainfall • More severe droughts or increased precipitation • changes to ocean circulation patterns
Mean Sea Level Rise Changes in Mean Sea Level Year
Summer Arctic Sea Ice Decline Comparison between 1979 & 2005
Early Fall Arctic Sea Ice Extent Sea Ice Extent (million km2) Year
Greenland Seasonal Surface Melting Surface melting
Permafrost melting Drunken forest
North Atlantic Tropical Storms 10-year running average Named Tropical Storms Year
Larsen B Ice Shelf • 220 m thick • Lost 5700 km2 (2x Rhode Island) • Reduction of 40%
1 Meter Sea Level Rise Waikiki http://www.soest.hawaii.edu/HMRG/FloodingOahu/index.php http://www.soest.hawaii.edu/coasts/sealevel/waikiki.html
Sea Level Rise • Destroys coastal habitat (e.g. salt marshes, mangroves) • Destroys human property • Increases pollution • Decreases freshwater supply Venice, 2008
Effect on Marine Life • Phytoplankton bloom due to light and temperature cues • Changes will impact food web • Hypoxia may result
Effect on Fisheries • Migrations are in response to temperature • May impact fisheries
Effect on Corals • Coral bleaching • Leads to loss of habitat and food for reef- dependent species
Currents • Oceanic conveyor belt may change ocean currents • Currents carry plankton • Bring food and oxygen • Distribute eggs and larvae • Remove wastes and pollutants
Salinity • Animals have a narrow range of tolerance • Glacial melting inputs lots of freshwater
Projected changes in precipitation • High latitudes = increased precipitation • Low and middle latitudes = decreased precipitation will worsen water shortages in developing countries
Acidity • CO2 makes water acidic • Corals and other calcium carbonate species can’t make skeleton • Impact on plankton development impacts food web • Coral calcification rate reduced 15-20% • Skeletal density decreased, branches thinner
Temperature • Higher temperature results in less O2 • - Results in hypoxia • Ice melting leaves no resting/hunting areas for polar bears • Antarctic Krill impacts food web
Invasive Species • Algae smothers coral • Invasive species out-compete natives
Weather Events • More severe weather patterns • El Niño • Hurricanes • Mudslides • Forest Fires • Drought
Sea Surface Temperature Dec 3, 2013 http://www.elnino.noaa.gov/
Origin and paths of tropical cyclones • Tropical cyclones are intense low pressure storms created by: • Warm water • Moist air • Coriolis effect
El Niño-Southern Oscillation (ENSO) • El Niño = warm surface current in equatorial eastern Pacific that occurs periodically around Christmastime • Southern Oscillation = change in atmospheric pressure over Pacific Ocean accompanying El Niño • ENSO describes a combined oceanic-atmospheric disturbance
El Niño • Oceanic and atmospheric phenomenon in the Pacific Ocean • Occurs during December • 2 to 7 year cycle • Sea Surface Temperature • Atmospheric Winds • Upwelling