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What is climate change? It is caused by humankind?

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Presentation on theme: "What is climate change? It is caused by humankind?"— Presentation transcript:

1 What is climate change? It is caused by humankind?

2 Weather can change from day to day, and even minute to minute. Climate remains relatively stable over many years, but we are experiencing climate change. Weather Weather refers to current conditions such as temperature, pressure, humidity and precipitation. Climate Climate refers to average weather over time and space. Seasons have a typical climate associated with them.

3  High frequency rays of light travel from the sun towards the earth, carrying energy. The high frequency rays are able to penetrate the earth’s atmosphere.  The high frequency rays of light strike the earth, causing it to warm up.  The heat radiates from the earth back towards the atmosphere. However, this energy has a lower frequency than the original rays of light.

4  Not all of this lower frequency energy can escape from the earth back into space – some of it is held in by the earth’s atmosphere.  As a result, the earth experiences a general warming effect; more heat energy is able to radiate onto the earth than is able to escape.  This is known as the greenhouse effect because it is similar to what happens when sun light radiates through a pane of glass into a greenhouse.



7  What are greenhouse gases?  Greenhouse gases are gases in the atmosphere that tend to absorb heat and prevent it from travelling back into space. They typically include water vapour, methane, and carbon dioxide as well as ozone.

8  How have humans contributed to global warming?  What greenhouse gas is associated with an increase in global temperature?  What do humans do that causes the production of this gas?  What are combustion reactions?

9 Natural Causes of Global Warming and Increased Greenhouse Gases

10  Methane gas (a greenhouse gas) is regularly released from Tundra and Wetlands areas, contributing to increased greenhouse effect.  Volcanic eruptions result in thick clouds of dust and gases that contribute to the greenhouse effect.  Changes in the earth’s solar radiation levels (sunspots) can have an impact on climate.

11  The earth wobbles: Although the earth rotates, it does not achieve perfect rotation. As a result, northern and southern areas are alternately exposed to increasing levels of heat. This effects climate for long periods of time.  Climate cycles are a regular occurrence on earth; there have been ice ages and periods of increased global temperature before.


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