Global Warming




Foundations of Science

Natural Cause: The universe behaves in a predictable way under “rules” that can be determined through observation and experimentation.

Uniformity: The “rules” are constant through space and time.

Foundations of Science

Parsimony: All other things being equal, the simplest explanation is the best.

Efficient Cause cause & effect


Scientific “Method”




Test & Observe


Repeat (as necessary)



Repeat (as necessary)

Environmental Science

interdisciplinary a way of looking at things scientific (& objective) interconnected systems human impact vs naturally occurring

• attempt to assign “responsibility”

What is the Environment?

definitions circumstances or conditions that surround an organism or group of organisms the complex of social or cultural conditions that affect an individual or community for humans - our home - well suited to our existence natural world


• plants

• sociological

• animals

• scientific

• earth

• air

• water

• technological

“Tragedy of the Commons”

common property usually owned by all (or the government) examples

• air

• water

• “air waves”

• public land commons are subject to poor use open, unregulated access benefits of use are focused costs are widely distributed

Common Property

must be carefully managed may privatize cost of use & effects

• internalization of costs

• laws and taxes commons (difficult)

• sale of public land

• sale of right to use

Global Climate Change

Earth’s climate has been changing for over 4.5 billion years wide scale of variability causes of variability

Sun physical Earth life

Research Priorities

What is the scale of the current change?

What are the causes of the current warming?

What are the effects of human activity?

Tools to Study Global


geologic record historical record real time observation mathematical modeling

Energy Balance

almost all energy ultimately from sun earth’s energy cycle incoming energy

• reflected 30%

• absorbed 70% (visible & IR) outgoing energy emitted as IR

• (as much energy as received)

Earth warmed by energy between absorption and emission energy circulated by air and water movement

Earth’s Temperature

atmospheric retention of heat

“greenhouse effect”



O vapor, CO


, CH


, CFC’s released by natural & human processes

Earth’s Temperature

historically over last billion years: warmer with ice ages current ice age

• 2MYA to present: cooler with “interglacials”

• last glacial advance ended 10,000 yrs ago

• generally warming since warming rapidly in last 150 years

Earth’s Temperature


2 changes currently: 0.03% of atmosphere recent highs

• “interglacial periods”

• 125K yrs ago and now releasing stored CO


• natural from rocks & plants

• humans current increase started in 1800's other “greenhouse” gasses human’s have increased release rate

Potential Effects of Global


local climate change more rain more violent storms sea level rise change in ocean circulation complex response

Current Research On-line e1/current/lectures/samson/climate_patterns/ ate?OpenDocument

More research and advocacy on-line

American Petroleum Institute:

industry site

Natural Resources Defense Council: environmental organization

Global Warming Information Page:

“astroturf” site (no direct supporters listed)

Global Warming Early Warning Signs:

“environmentalist” site (supporters listed) the Global Simulation Workshop commercial “environmentalist” site

worldwide use of energy

overall oil - 36% coal - 26% natural gas - 23% nuclear - 7% biomass – 6% hydro - 2% geothermal & wind - 1%

U.S. consumes ¼ of worlds energy