GREENHOUSE EFFECT

Is it getting warmer?

definition

• Sun’s rays are trapped by greenhouse gases in troposphere

• Heat is trapped like a greenhouse

Is this bad?

• Not all• Need greenhouse

effect to warm earth

• But…• Too much heat

creates global warming (enhanced greenhouse effect)

EARTH

• Without Greenhouse Effect: 32º F

• With Greenhouse Effect: 57 º F

Mars- too little Venus- too much

Enhanced Greenhouse Effect

Human contribution to Greenhouse Gases

GHG

• Greenhouse gas

• Any gas the traps in heat

• Review: What gases make up the atm.?

Greenhouse gases

• Water Vapor– H2O

– Sources (natural)• evaporation• volcanoes

– Concentration• 1-3 ppm

– Lifetime• A few days

– GWP= na

But….Co2 is the biggest man-made

greenhouse gas

Greenhouse gases

• Carbon dioxide-– CO2

– Sources• Burning fossil fuels

• Deforestation (trees use Co2)

• Cement production

– Concentration• 379 ppm (largest man-made contributor)

– Lifetime• varies

– GWP= 1

What do we use fossil fuels for?

• Coal– electricity

• Oil– Gasoline– plastics

• Natural gas– heating

Greenhouse gases

• Methane– CH4

– Sources• Agricultural waste

• Fossil fuels

• Land fills

– Concentration• 1.77 ppm = 1770 ppb

– Lifetime• 12 years

– GWP= 23

Greenhouse gases

• Nitrous Oxide– N20

– Sources• Fertilizers• Combustion of ff

– Concentration• .319 ppm = 319 ppb

– Lifetime• 114 years

– GWP= 296

Greenhouse gas producers

GH gases and climate graph

Are we warming?

Rising sea level by 2080(projected)