22-12-2012, 06:55 PM
GLOBAL WARMING
GLOBAL WARMING[.ppt (Size: 3.31 MB / Downloads: 44)
Introduction
Is the world getting warmer?
If so, are the actions of mankind to blame for earth’s temperature increases?
What can/should be done about these issues?
History of Earth’s Climate
Earth formed ~4.6 billion years ago
Originally very hot
Sun’s energy output only 70% of present
Liquid water present ~4.3 billion years
Life appeared ~3.8 billion years ago
Photosynthesis began 3.5-2.5 billion years ago
Produced oxygen and removed carbon dioxide and methane (greenhouse gases)
Earth went through periods of cooling (“Snowball Earth”) and warming
Earth began cycles of glacial and interglacial periods ~3 million years ago
Blowing Up Your World
How many of you eat fresh vegetables instead of canned or frozen?
Fresh vegetables cook more quickly and are usually more nutritious than frozen or canned foods. Canned and frozen vegetables are often over-processed, contain additives, contribute to air pollution (transport and packaging) and add to our waste problem. 4 pts u