RESOURCE CARD 1: GOLDILOCKS

Too much : The of Venus, like , is nearly all . But Venus has about 300 times as much carbon dioxide in its atmosphere as and Mars do, producing a runaway greenhouse effect and a surface hot enough to melt lead.

The atmosphere on Venus is much denser than the ones on Mars or Earth. If we represented the with beans, Venus would have 9000 beans compared to 100 on Earth.

Temperature and Pressure Comparison Atmospheric Concentrations of Greenhouse Gases (%) on Venus Surface Pressure Relative to Earth 90 Carbon Dioxide (CO2) 96.5

Major Greenhouse Gases (N2) 3.5 CO2

Estimated Temperature if no -46 (O2) Trace Greenhouse Gases (°C) Actual Temperature (°C) 477 (Ar) 0.007

Temperature Change Due to GHG +523 Methane (CH4) 0

The relative distance from the has some influence on planetary temperature, but the greenhouse gases and atmospheric density have more of an impact on temperature. Venus has an extremely dense atmosphere (with a surface pressure 90 times that relative to Earth's atmosphere). Conversely, Mars has an extremely thin atmosphere (with a surface pressure less than 1/100th of that relative to Earth's atmosphere). RESOURCE CARD 2: GOLDILOCKS MARS

Not enough greenhouse effect: The Mars has a very thin atmosphere, nearly all carbon dioxide.

Because of the low , and with little to no methane or to reinforce the weak greenhouse effect, Mars has a largely frozen surface that shows no evidence of .

Temperature and Pressure Comparison Atmospheric Concentrations of Greenhouse Gases (%) of Mars Surface Pressure Relative to Earth 0.007 Carbon Dioxide (CO2) 95

Major Greenhouse Gases Nitrogen (N2) 2.7 CO2

Estimated Temperature if No -57 Oxygen (O2) 0.13 Greenhouse Gases (°C) Actual Temperature (°C) -47 Argon (Ar) 1.6

Temperature Change Due to GHG +10 Methane (CH4) 0

The relative distance from the Sun has some influence on planetary temperature, but the greenhouse gases and atmospheric density have more of an impact on temperature. Mars has an extremely thin atmosphere (with a surface pressure less than 1/100th of that relative to Earth's atmosphere). RESOURCE CARD 3: GOLDILOCKS EARTH

The right amount of greenhouse effect?

The Earth has small amounts of carbon dioxide and other greenhouse gases, but working together they create a balanced system that helps to support life. US!

This model does not take into account the importance of water vapor as a greenhouse gas. Water vapor both helps warm the planet, when it is in the form of a gas, and cool the planet, when it is in a reflecting .

Temperature and Pressure Comparison Atmospheric Concentrations of Greenhouse Gases (%) on Earth Surface Pressure Relative to earth 1 Carbon Dioxide (CO2) 0.03

Major Greenhouse Gases Nitrogen (N2) 78 H2O,

CO2 Estimated Temperature if No -18 Oxygen (O2) 21 Greenhouse Gases (°C) Actual Temperature (°C) 15 Argon (Ar) 0.9

Temperature Change Due to +33 Methane (CH4) 0.002 Greenhouse Gases

The relative distance from the Sun has some influence on planetary temperature, but the greenhouse gases and atmospheric density have more of an impact on temperature. Venus has an extremely dense atmosphere (with a surface pressure 90 times that relative to Earth's). Conversely, Mars has an extremely thin atmosphere (with a surface pressure less than 1/100th of that relative to Earth's).