GREENHOUSE EFFECT GREENHOUSE EFFECT l l Earth is

GREENHOUSE EFFECT

GREENHOUSE EFFECT l l Earth is unique in the solar system in that it is the only planet that supports life as we know it. Several factors account for this: – Position near the sun: not too close, not too far – Abundance of water – Right mixture of chemical compounds needed for life – Right types of gasses in the right combination making up our atmosphere

GREENHOUSE EFFECT Let’s look at the last factor… Right types of gasses in the right combination make up our atmosphere Why is this so important?

GREENHOUSE EFFECT l l The earth’s atmosphere is a protective blanket which surrounds our planet. It allows the right amounts of sun’s energy in and out, creating a climate that is supportive of life

SUN’S ENERGY l l The sun’s energy reaches the earth in the form of electromagnetic radiation. Electromagnetic radiation includes visible light, infrared (heat), ultraviolet wave lengths and others forms of energy.

SOLAR ENERGY l Two things can happen to solar radiation as it approaches earth’s atmosphere 1. Solar radiation can be reflected back into space 2. Solar radiation can be absorbed by clouds, gases like ozone or earth’s surface - or scattered by the atmosphere.

SOLAR RADIATION l l l Some of the solar radiation is reradiated or emitted by the earth in the form of long-wave radiation This long-wave radiation is absorbed by certain gasses in the earth’s atmosphere. These gasses are called “greenhouse gasses”

GREENHOUSE GASSES Naturally Occurring l Water Vapor l Methane l Nitrous Oxide l Carbon Dioxide Influenced by humans l Carbon Dioxide l Nitrous Oxide l Methane l CFC’s l Ozone (? )

The level of greenhouse gases can be affected by man-made and natural processes

MAN-MADE PROCESSES l l Burning fossil fuels→CO 2 and NOx Removing vegetation (deforestation)→CO 2 Using aerosols→CFC Polluting of oceans and waterways →methane

NATURAL PROCESSES l l l Volcanic Eruptions Carbon Cycle Water Cycle Decay→methane Oceans and bacteria in soil→nitrous oxide

MAN-MADE CONTRIBUTIONS l l Man-made contributions to greenhouse gases are potentially devastating The rise in greenhouse gases, especially carbon dioxide, are being attributed to a general rise in earth’s temperature.

These two graphs show the relationship between carbon dioxide concentrations in ice core data/Mauna Loa data and global average temperatures. There seems to be a direct correlation between the two

So what are the consequences of an overall rising temperature on Earth?

CONSEQUENCES l Several theories exist as to what may become of our earth if temperature continue to rise l l Rise in sea level due to melting glaciers Balance of salt water in oceans will change, possibly affecting wildlife More tropical, dry weather in parts of world Increase in severe weather

rst. gsfc. nasa. gov/Sect 16_2. html

VIDEO CITATIONS l Greatest Discoveries with Bill Nye: Earth Science. Discovery Channel School. 2005. unitedstreaming. 1 July 2007 <http: //www. unitedstreaming. com/>