1. Earth’s Climate System

2. Factors Affecting Climate Change
Earth is surrounded by a layer of gases called the atmosphere.
The characteristic pattern of weather conditions within a region averaged over a period of time is called the climate.

3. Is climate change new?
No, climate change is a natural part of Earth’s history.
For example, thousands of years ago, thick ice sheets covered most of Canada and a large portion of the United States.

4. Factors Affecting Climate Change
Make a list of as many factors that affects climate as you are able….

5. Factors Affecting Climate Change
1. The Sun The Earth
3. The Atmosphere 4. The Hydrosphere
   
5. Moving Continents 6. Human Activity

6. 1. The Sun
Solar energy hits the Earth’s surface and the heat leads to winds, rain and other features of weather.
A sunspot maximum occurs every 11 years, which is thought to have added to climate change in the past.

7. 2. The Earth: Orbit, Tilt and Rotation
Eccentricity: over years our orbit goes from circular to elliptical, and back. This affects the length of seasons.
Tilt: over years tilt changes by about 2.4. When closer to upright the seasons are less variable. When more tilted the seasons are more variable.
Wobble: Earth is not a perfect sphere, so it wobbles a bit on its axis as it rotates. Has the same impact as tilt.

8. 2. The Earth: Latitude
Climate is hotter at the equator due to the angle at which the Sun’s rays hit Earth, not how close we are to the Sun.

9. 3. Atmosphere Made of mainly nitrogen, oxygen and water vapour.
Greenhouse Effect: natural warming caused when gases in Earth’s atmosphere absorb thermal energy from Sun and Earth.
Without it, Earth would radiate it’s energy back into space and it would be a lot colder on Earth.

10. 3. Atmosphere
Winds
Wind starts as an uneven heating of the Earth’s surface which causes high and low pressure areas and followed by the movement of air from the high pressure to the low pressure.
Ocean Currents
Energy from the moving air is transferred to the surface of the water, causing the water to move and to redistribute heat.

12. 4. Hydrosphere Water in all its forms composes the hydrosphere.
Because water has a large specific heat capacity (it takes a lot of energy to raise the temperature of a given volume of water) the Oceans and lakes act as stores of heat which is then moved around the planet in ocean currents.

14. 5. Tectonic Plates
Earth’s outer layer is made of tectonic plates which move a few cm each year.
Shapes of oceans and continents are always changing which alters the movement and distribution of heat at the surface of the planet.

15. 5. Volcanic Eruptions
Movement of tectonic plates produces volcanic eruptions.
Ash reflects solar radiation back to space creating a cooling effect on the global climate.
Eruptions may also raise global temperatures by emitting greenhouse gases.

16. 6. Human Activity
However …none of these factors can explain the warming trend we are experiencing now.
There is growing evidence that the present change in climate is at least partly anthropogenic in origin (caused by humans).
Due to burning fossil fuels (cars, factories, farming, home, electricity, etc) we are releasing huge amounts of greenhouse gases into the atmosphere.

17. Reconstructing Paleo-climates
Nova – Ice Mountain
Ice Core Graphing Activity