Pollution and the Role of the Courts in Remedying Pollution Problems
Environmental Problems Climate Change Pollution Overfishing.
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Transcript of Environmental Problems Climate Change Pollution Overfishing.
© 2011 Pearson Education, Inc.
Determining Causes of Earth’s Climate Change
• Paleoclimatology • Proxy data – indirect
evidence using natural recorders of climate variability– Sea floor sediments– Coral deposits– Glacial ice rings– Tree rings– Pollen – Historical documents
© 2011 Pearson Education, Inc.
Natural Causes of Climate Change
• Solar energy changes, Variations in Earth’s Orbit, Volcanic eruptions, Movement of Earth’s Plates
• Linked to Pleistocene Ice Age, Little Ice Age, Medieval Warm Period
• Recent change unprecedented– More likely result of human activity than
natural causes
Global Warming: Causes
• Green house gases (chloroflourocarbons =CFCs, methane, CO2, water vapor)
• Increasing CO2
– Deforestation & burning fossil fuels
© 2011 Pearson Education, Inc.
Global Warming• The 8 warmest years have occurred since 1998• Earth’s surface temperature has risen 0.8°C (1.4°F) in last
140 years.
© 2011 Pearson Education, Inc.
Changes in the OceansChanges in deep-water circulation • North Atlantic especially sensitive• Melting glaciers• Warmer surface waters
© 2011 Pearson Education, Inc.
Changes in the OceansPolar Ice Melting• Arctic amplification • Loss of more than
2 million square kilometers (800,000 square miles) of Arctic sea ice in last decade
• Loss of ice = enhanced warming due to lower albedo
© 2011 Pearson Education, Inc.
Changes in the OceansPolar Ice Melting• Arctic ice melting
affects polar bear survival.
• Food sources are dwindling for human Arctic dwellers.– Marine species migration
© 2011 Pearson Education, Inc.
Changes in the Oceans• Rising Sea Level –
already occurring • Main contributors:
– Melting of Antarctic and Greenland ice sheets
– Thermal expansion of ocean surface waters
– Melting of land glaciers and ice caps
– Thermal expansion of deep-ocean waters
© 2011 Pearson Education, Inc.
Rising Sea Level
• Severely affect areas with gently sloping coastlines– U.S. Atlantic and Gulf Coasts
• Models predict rise between 0.5 and 1.4 meters (1.6 and 4.6 feet) by year 2100
• Affects coastal ecosystems like corals
© 2011 Pearson Education, Inc.
Changes in the OceansOcean acidity increase• Some atmospheric
carbon dioxide dissolves in ocean water.– Acidifies ocean
• Threatens calcifying organisms– Coccolithophores– Foraminifers– Sea urchins– Corals
Marine Pollution
• The introduction into the ocean by humans, substances that changes the physical, chemical or biological environment
Fig. 15-28, p. 368
Each year 240 million gallons of used motor oil are dumped in storm drains…22x the amount spilled by Exxon Valdez
Marine Pollution
• Bioamplification – even small amounts of pollutants can have large effects
• DDT example
DDT in water 0.000003 ppm
DDT in fish-eating birds (pelicans) 25
ppm
Concentration has increased 10 million times
DDT in small fish (minnows) 0.5 ppm
DDT in small zooplankton 0.04 ppm
DDT in large fish
(needlefish) 2 ppm
Stepped Art
Fig. 15-32, p. 371
Marine Pollution
• Eutrophication– Excess nutrients in water also lead to problems
• HABs
• Oxygen depletion
© 2011 Pearson Education, Inc.
Marine Fisheries • Commercial fishing• Most from continental
shelves• Over 20% from areas of
upwelling that make up 0.1% of ocean surface area
© 2011 Pearson Education, Inc.
Overfishing
• Fish from standing stock – the mass present in the ecosystem at any given time
• Overfishing – fish stock harvested too rapidly, juveniles not sexually mature to reproduce
• Reduction in Maximum Sustainable Yield (MSY)
© 2011 Pearson Education, Inc.
Overfishing • 80% of available fish
stock fully exploited, overexploited, or depleted/recovering
• Large predatory fish reduced
• Increased fishing effort, decreased stocks
Overfishing: Causes• Hard to estimate maximum sustainable
yield– Must know pop. size, growth & reproduction,
life span
• International waters
• Economic Needs
Bykill or By-catch
• Other species are accidentally caught
• Drift nets – banned in 1993
• “Dolphin-Safe Tuna”
• Turtle exclusion devises (TEDs)
TEDs
© 2011 Pearson Education, Inc.
Fisheries Management
• Consumer choices in seafood
• Consume and purchase seafood from healthy, thriving fisheries– Examples: farmed seafood, Alaska salmon
• Ecosystem-based fishery management
• Avoid overfished or depleted seafood– Examples: tuna, shark, shrimp