Greenhouse Effect

Sun Greenhouse Effect To a certain degree, the earth acts like a greenhouse.  Energy from the Sun penetrates the glass of a greenhouse and warms the air and objects within the greenhouse. The same glass slows the heat from escaping, resulting in much higher temperatures within the greenhouse than outside it. 

The sun sends out energy as heat and light The sun sends out energy as heat and light. This energy comes to our earth during the day time. Some of the sun’s rays get ‘trapped’ in the atmosphere. Some of them get reflected back into space. The ones which get through the atmosphere warm the earth up.

All the time, the earth radiates heat into space, which cools it down All the time, the earth radiates heat into space, which cools it down. We only really notice this at night, when there is no heating from the sun. Some of the heat going out is trapped by the atmosphere. This is what makes our planet warm enough to live on. .

Why does the atmosphere trap heat? The atmosphere is the air around the surface of the earth. It is made from a mixture of gases. Some of the gases act like a blanket, trapping heat. These gases are called ‘greenhouse gases’. This is known as the ‘Natural Greenhouse Effect’. Without it, the earth would be much colder.

The greenhouse effect Teacher notes This four-stage animation can be used to illustrate the principles of the greenhouse effect. Students could be asked to consider the impact of rising greenhouse gases on the natural phenomenon of the greenhouse effect.

Is the Greenhouse Effect Good or Bad? It is necessary for life (good)- it keeps our climate toasty warm and prevents it from fluctuating (changing) too much. It is bad when: there are too many greenhouse gasses and the climate changes (GLOBAL WARMING)

Consider the Greenhouse effect on other planets Mercury Venus

What is Global Warming? Global warming doesn’t just mean that the earth gets hotter, it means that the whole climate is changing It is caused by an increase in Greenhouse Gases in the Atmosphere

Natural Greenhouse effect Enhanced Greenhouse effect Atmosphere has more greenhouse gases Heat radiates from the earth Heat radiates from the earth Less heat goes out to space Some heat goes out to space Atmosphere traps some heat Atmosphere traps more heat Quite a lot of heat is trapped and the earth is warm enough for life. More heat is trapped and causes global warming

What causes an Increase in Greenhouse gases? 1. CARBON DIOXIDE is added to the atmosphere when people burn coal, oil (gasoline), and natural gas (FOSSIL FUELS), for transportation, factories, and electricity.

What else causes an increase in Greenhouse gases? 2. Deforestation, or the clearing of forests, also increases the amount of CARBON DIOXIDE in the air because in photosynthesis plants take in carbon dioxide and remove it from the atmosphere, they make oxygen.

What else causes an increase in Greenhouse gases? 3. Volcanoes, fires, and respiration (breathing) also add CO2 to the atmosphere.

What else causes an increase in Greenhouse gases? 4. Methane is produced when garbage is buried in landfills, from animal waste and from other natural sources.

The carbon sink

Preventing global warming Energy efficiency means less fuel burned to make electricity. Fuel cell buses. Renewable energy sources like water power, solar, wind farms, bio fuels. Nuclear power. The Kyoto agreement to reduce CO2 emissions. Reduction in large scale deforestation

Watch Video and Answer Questions https://www.youtube.com/watch?v=pnrlSMCBeR8

Watch Video and Answer Questions In workbook do pages: 113 142 151 (climate change questions)