4.4: Climate change. Changes in Carbon Dioxide in our Atmosphere in the last 100+ years. Why has carbon dioxide increased? Carbon Dioxide Levels (ppm)

4.4: Climate change

Changes in Carbon Dioxide in our Atmosphere in the last 100+ years. Why has carbon dioxide increased?

Car

bon

Dio

xide

Lev

els

(ppm

)

Greenhouse gasesCarbon dioxide and water vapor are the most significant greenhouse gases.

Carbon dioxide Water vaporReleased by cell respiration and combustion.

Removed by photosynthesizing plants & dissolving in the ocean.

Formed by evaporation from the oceans and transpiration in plants.

Removed by rainfall and snow.

Methane Nitrous oxidesThird most significant greenhouse gas.

Released from water logged areas.

Released from melting ice in polar regions & extracting fossil fuels.

Oxidises into CO2 over time.

Released naturally by bacteria, agriculutre and car exhausts.

The greenhouse effect1.Solar radiation travels to the surface of the earth.2.This radiation is absorbed by the earth’s surface.3.Earth’s surface emits (releases) radiation in the form of Infrared radiation(also called heat)4.This infrared radiation (heat) tries to leave earth but gets trapped by the greenhouse gases.5.The heat is trapped close to earth’s surface and thus, keeps the planet warm.

COPYRIGHT PEARSON PRENTICE HALL


The Greenhouse Effect Explained a) Short wave solar radiation (light)

b) light penetrates the atmosphere and passes through the molecules of the atmosphere

c) Absorption by the ground and conversion to long wave infrared radiation (heat)

d)This warms the planet

e) Some infrared is lost to space as heat

f) Atmospheric gases particularly, carbon dioxide, methane and nitrogen oxides.

g) Greenhouse gases absorb infra-red radiation and scatter this rather than letting it escape to space. In effect this traps the heat energy.

h) Some light reflects off the outer surface of the atmosphere and never enters

Note that if this 'greenhouse' effect did not exist the average global temperature would be -17 C.

Enhanced Greenhouse Effect• Enhanced greenhouse effect is the concern that the activities of human's may

be increasing the levels of carbon dioxide and other 'greenhouse gases’ in the atmosphere.

• That this may lead to increased global temperatures and climate change



The enhanced greenhouse effect.

•Increase in carbon dioxide and other greenhouse gases (methane, oxides of nitrogen) will increase the particles in the greenhouse gas layer

•Therefore more infra-red will be absorbed, scattered and retained as heat.•The average global temperatures will rise. Some models suggest as much as 40C in the next 50 years.

•An enhanced greenhouse effect is predicted to cause global climate changes. This is often referred to as global warming but whilst the average global temperatures may rise the local effects may vary widely.

Online tutorial of greenhouse effect:

http://earthguide.ucsd.edu/earthguide/diagrams/greenhouse/


http://earthguide.ucsd.edu/earthguide/diagrams/greenhouse/

Online resources relating to Climate changehttp://channel.nationalgeographic.com/channel/content/earth-the-biography/interactive/main.html

https://www.climateinteractive.org/tools/climate-bathtub-simulation/

http://channel.nationalgeographic.com/channel/content/earth-the-biography/interactive/main.html

https://www.climateinteractive.org/tools/climate-bathtub-simulation/

Documents

4.4: Climate change. Changes in Carbon Dioxide in our Atmosphere in the last 100+ years. Why has carbon dioxide increased? Carbon Dioxide Levels (ppm)