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.