Global Warmingby

Adam Leeper and Jennifer Fox

Global Warming

• A gradual increase of planet-wide temperatures.

• Greenhouse effect: Swedish chemist suggested in 1896 that we were increasing the Earth’s natural greenhouse effect, leading to global warming.

The Greenhouse Effect

• A natural effect, due to normal amounts of carbon dioxide and water vapor in the atmosphere.

• The gases absorb infrared radiation to keep the earth at a suitable temperature for life.

The Greenhouse Gases

• CH4, Methane

• H2O, water vapor

• CO2, Carbon Dioxide

• N2O, Dinitrogen Oxide

Carbon Dioxide, CO2

• Natural Sources: Respiration, decay of organic matter, “natural” forest fires.

• Human Sources: combustion of organic resources such as fossil fuels and wood, for everything from industry to transportation.

• Up 25% since Industrial Revolution.

• Atmospheric life 50-200 years.

Methane, CH4

• Natural Sources: Wetlands and termites.

• Human Sources: cattle farming, rice fields, land fills, coal mining, David’s little brother, petroleum and natural gas processing.

• Up 145% (!) since IR• Life 12 years

Nitrous Oxide, N2O• Natural Sources: “Bacterial Action”• Human Sources: Nitrogen Fertilizers• Up 15% since Industrial Revolution.• Atmospheric life of 120 years.

Water Vapor, H2O• Natural Sources: Evaporation (!)• Human Sources: Combustion of

hydrocarbons.

Recorded Effects

Over the last century:• Average global temperatures have

increased by about ½ degree Centigrade.• There has been a 1% increase in average

precipitation.• Sea levels have risen by about 15-20 cm,

6-8 inches. (The Dutch are even further underwater ;-)

Theoretical Effects:• Health: Life cycles of pathogens and insects

made easier when warm. Disease thrives.• Agriculture: Changed crop yields; some

crops will enjoy the increased temp, others will suffer.

• Forests: Dryness and droughts will make forest fires flare. (No pun intended)

• Water: More extreme conditions, from more flooding to longer droughts.

• Coasts: low-land flooding.• Habitats will change or be destroyed;

species relying on cold/ice will be screwed.

Particulates• Small particles, products from combustion and

heavy industry; volcanoes.

• Counteract greenhouse gases by deflecting sunlight, scattering radiation.

• Provide something for water vapor to condense on, adding cloudiness to reflect radiation and increase precipitation, ultimately cooling the Earth.