ESC 110: Global Climate Change: Impact on Biological Systems Changes in glacial ice mass- Indication...
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Transcript of ESC 110: Global Climate Change: Impact on Biological Systems Changes in glacial ice mass- Indication...
ESC 110: Global Climate Change: Impact on Biological Systems
Changes in glacial ice mass-Indication ofClimate change
Bob EdmondsForest ResourcesReading p. 195-209
Lecture Topics
1. Is global warming really happening?
2. Greenhouse gases and increases in CO2
3. Climate in the past, present and future
4. What effect will climate change have?
5. What can we do about it?
1. Is global warming really happening?
GCC: Fact or Fiction
From an environmental textbook: One of “the two most immediate global environmental threats humans face is climate change caused by greenhouse gases. This is caused by the introduction of large quantities of human-produced gases into the atmosphere.” Are these statements true? Does everyone agree with them?
GCC: Givens
• Climate will change (because it has changed).• Carbon dioxide levels are increasing in the
atmosphere• The greenhouse effect is real (and important).
• How will the climate change and how much will the climate change?
• Is the change natural or due to human activities?• If there is climate change, will it affect me?
GCC: Questions
Human-Caused Global Climate Change
• IPCC (2001) released report stating “recent changes in the world’s climate have had discernable impacts on physical and biological systems.”– Concluded human activities must be at least
partially responsible.
2. Greenhouse gases and increases in CO2
GCC: Greenhouse effect• The greenhouse effect is caused by trace gases in the
atmosphere (water vapor, carbon dioxide, methane, others)
2
Greenhouse Gases
• Carbon Dioxide - Fossil-fuel burning.• Atmospheric levels increasing steadily.
• Methane - Ruminants, Coal-mines• Absorbs more infrared than CO2.
• Chlorofluorocarbons (CFC’s) - Refrigerants• Declined in recent years
• Nitrous Oxide - Burning organic material
• Sulfur Hexafluoride - Electrical insulation
Table 9.3
GCC: Changes in a greenhouse gas
IncreasingPatternBiological activityHuman activity
3. Climate in the past, present and future
GCC: Present Temperature Change to Historical
Fig. 9.9c
Fig. 9.9d
West Olympic Coastal Division, Washington Temperature(C)Climate Division (01), 12 month period ending in December
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Cascade Mountains West Division, Washington Temperature (C)Climate Division (05), 12 month period ending in December
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CO Drainage Basin (S) Division, Colorado Temperature (C)Climate Division (02), 12 month period ending in December
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South Central Division, Florida Temperature (C)Climate Division (04), 12 month period ending in December
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LARGE SCALE CLIMATE PERTURBATIONS- EL NINO AND LA NINA
El Nino Southern Oscillation
El Nino Southern Oscillation
• Large pool of warm surface water in Pacific Ocean moves back and forth between Indonesia and South America.– Most years, the pool is held in western Pacific
by steady equatorial trade winds.• Every three-five years the Indonesian low collapses
and the mass of warm surface water surges back east.
El Nino Southern Oscillation
– During an El Nino year, the northern jet stream pulls moist air from the Pacific over the U.S.
• Intense storms and heavy rains.– During intervening La Nina years, hot, dry weather is
often present.
GCC: Climate Change: Predictions
Know CO2 will continue to increaseGreenhouse effect should increaseTherefore temperature should increase
Four responses:• A disaster• The best news ever• Do not know enough• Natural cycles dominate
MODEL
The Pacific Northwest is likely to have hotter, drier summers and warmer, wetter winters.
4. What effect will climate change have?
EFFECTS OF CLIMATE CHANGE ON:
Agriculture - increase agricultural yields in Canada; could reduce in U.S.
Forests - change species distributions, more forest firesWater – stream flows could be less in some areas; big competition for
waterFish - could increase stream temperatures; reduce salmonCoral reefs - killing of reefs (bleaching)Wildlife – some species could go extinct; reduce biodiversity
People - sea level rise will flood coastal cities, water suppliescould be reduced, more fires, hotter in summer(more need forair conditioning and energy), reduced snow for skiing.Could result in rapid global cooling (breaking the conveyor belt)
Modern Glacial Retreat in Switzerland
THEN
NOW
Consequences of Changes in Global Snow/Ice Coverage
• Northern latitudes have warmed more than the global average.
• Spring is coming sooner to northern latitudes.
• Examined 10 plus year record of almost 300 different species: Changes in phenology (when leaves appear, migration, nesting, hibernation) and distribution and abundance
• Seasonal water shortages
• Loss of glaciers (e.g., Glacier Nat’l Park)
Consequence of this warming?
Feedback: Less snow, means warmer winters, earlier springs.Further:Changes in species distributionChanges in biological communities
GCC: Implications on PlantsSpecies responses
Disturbance regimes
Rapid melting of polar ice in the North Atlanticcould break the heat conveyer belt in the oceans andcause rapid cooling. Scarey!!
5. What can we do about it?
GCC: Let’s assume we need to do something, then what?
• Conservation – reduce fossil fuel energy use• Alternative energy sources• Regulate carbon dioxide emissions ( 1997
Kyoto Protocol – U.S. has not signed)• Carbon tax• Use plants (trees) to take up or sequester the
carbon.
GCC: Solutions with plants• Balance the net gain of global carbon by the
atmosphere through planting young forests requires over 109 hectares of young forest, ~14 times the size of Washington State.
• Balancing the CO2 input from the US alone would require an area ~3 times Washington State ( ~1.2 times the size of California)
• If you burn it then it goes back to the atmosphere. Could bury trees in the ocean.
GUILT
Global Climate Change: Summary.
Climate has changed in the past and will in the futureHumans have contributedClimate change has consequencesWe are involved in a massive experimentYou are the observers of this experiment.You will need to address whether & when something should be done & how.