Chapter 1: A Changing Planet

earth=about 4.6 billion yrs old

humans=about 2 million yrs

thermosphere

mesophere

stratospause

stratosphere

tropopause

troposphere

-temperature declines as you travel up the atmosphere

Aerobic Respiration-combines organic molecules + O2, produces CO2, water, and energy

-releases energy at a greater rate than Anaerobic respiration

-facilitated evolution

*Climate

-average conditions of atmosphere and surface

-ex; temperature, humidity, cloudiness

-different than weather (local and immediate, changes on diff scales)

-affected by 1. sunlight and 2. composition of earth's atmosphere

-sunlight warms planet and drives circulation of atmosphere and oceans

1. sunlight warms, bring energy

2. earth returns energy to space   (creates balance, maintains constant temp)

3. Greenhouse gases block outgoing energy and make earths temp higher than it would be otherwise

GG=water vapor, CO2

Climate depends on rate at which earth receives solar energy or concentration of atmospheric GG

*sun has become stronger but earth has been warmer at others points in history

Negative Feedback-earth warms and earth atmosphere system responds by countering warming. Earth cools and EAS responds by counter cooling

*predicted 4 snowballs=extreme changes

Earth's Energy Sources: Flows and Fuels

Flows: streams of energy, bring energy no matter what. ex; sunlight

Fuels-stored usually in molecules or atomic nuclei. stored until actively liberated

*solar energy quickly returned back to space (relative)

Thermal energy=heat

Geothermal energy=mix of primordial heat liberated in gravitational accretion decay of radioactive elements

*The temp difference of core and surface drive steady energy to surface

Tidal energy-motions of earth and moon

*Main energy=sunlight, geothermal, tidal

Fossil Fuels

-nonrenewable!

-supply vast  majority of energy for human society

-coal, oil, natural gas

-relatively new

-form at millx slower than we consume

Nuclear Fuels

-always have been on earth

-uranium

-thorium

-truly nonrenewable-no terrestrial process that can create them

*Hydrogen could supply us with 40 bill yrs, 10x longer than the sin will shine

-enourmous amts

-yet haven't learned how to use

Antropogenic-human caused