ESC 110: Global Climate Change: Facts & Fiction

Olympic rain forest isn't going awayTuesday, February 26, 2002

DAVID L. PETERSONRESEARCH SCIENTIST

Olympic rain forest doomed by global warming, report fearsFriday, February 8, 2002

By ROBERT McCLURESEATTLE POST-INTELLIGENCER REPORTER

Chapter 18 of text

GCC: Fact or Fiction

From your text: 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?

GCC: Questions

GCC: Greenhouse effect• The greenhouse effect is caused by traces

gases in the atmosphere (water vapor, carbon dioxide, methane, others)

• 1.4oF• -17oC• 59oF• 15oC

• “Steady”

2

GCC: Changes in a greenhouse gas

GCC: Changes in a greenhouse gas

IncreasingPatternBiological activityHuman activity

GCC: Why is the greenhouse gas changing? Human activity?

GCC: Consequences of Increased CO2

• If CO2 has increased,• CO2 is a greenhouse gas and• Greenhouse gases warm the earth then• The earth should be warmer! Is it?• Yes• But

– Surface– Trend– Solar– Aerosols

GCC: Present Temperature Change to Historical

GCC: Present Temperature Change to Historical

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

GCC: Implications on PlantsSpecies responses

Disturbance regimes

GCC: Implications on Plants: How do we know?

GCC: Let’s assume we need to do something, then what?

• Conservation• Alternative energy sources• Consumption• Regulate carbon dioxide emissions (Kyoto

Protocol)• Carbon tax• Use plants (trees) to take up or sequester the

carbon.

GCC: Solutions with plants

Could the earth’s biological systems accumulate sufficient CO2 to balance emissions?

Anthropogenic release

Net uptake by terrestrial vegetation

Net uptake by the oceans

+6.3 - +7.0

-0.7

-2.3

Gain by the atmosphere +3.3 - +4.0

1 Giga ton = if the carbon was solid, 81 Safeco Fields and if the carbon was in the form of pure carbon dioxide, 392 Safeco Fields

GCC: Solutions with plants• To balance the net gain of 4 Gt of carbon by

the atmosphere through planting young forests, and,

• assuming an increase in production of 5 t ha-1 over the vegetation replaced, e.g., replacing an older, natural forest with a forest crop,

• 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)

Global Climate Change: Where are we?

Olympic rain forest doomed by global warming, report fearsFriday, February 8, 2002

Human contributionClimate has changedClimate change has consequencesInvolved in a massive experimentYou are the observers of this experiment.You will need to address when something should be done & how.