1. Climate Changes

2. Climate vs Weather
Weather and climate are different. Both weather and climate are measurable, and to a a certain extent, predictable.

3. Weather describes day to day changes in atmospheric conditions.

4. Climate
Climate describes the typical weather patterns for a given location over a period of many years.

5. Factors that affect climate
ONE: LATITUDE
As latitude increase, the average intensity of solar energy (heat) received at Earth’s surface decreases.
So, what happens to the sun’s rays and that heat energy in the temperate zones where we live, or in the polar zones?

6. Factors that affect climate
TWO: ELEVATION -The higher the elevation is, the colder the climate. The following slide shows two southern asian cities: Kathmandu and Bangalore. Kathmandu is located to the south of the Himalayas and Bangalore is significantly lower in elevation.

7. What does the data show?

8. What does the data show?
Bangalore is lower in elevation and lower in latitude, which leads to slightly higher average temperatures during the summer months and much higher average temperatures during the winter months

9. Factors that affect climate?
THREE: Large bodies of water -Large bodies of water such as lakes and oceans have an important effect on the temperature of an area because the temperature of the water body influences the temperature of the air above it.

10. Factors that Affect Climate
FOUR: TOPOGRAPHY -Topographic features like mountains influence the amount of precipitation that falls over an area. How may the climates on the windward and leeward sides of the mountains be different?

11. Factors that affect Climate
FIVE: Circulation in the atmosphere -Global winds distribute heat and moisture around the Earth

12. Factors that affect Climate
SIX: Vegetation
-Vegetation can affect both temperature and the precipitation patterns in an area.
-How might this affect the atmosphere and precipitation?

13. So the difference?
Climate VS Weather
Weather is the differences from day to day. Climate is a specific area’s normal or typical conditions throughout many years.

14. Climate CHANGE
Climate is always changing. Some are short-term, and some are long-term.
Let’s look at some natural factors that can cause these changes:

15. 1. Plate tectonics
Geographic changes in the Earth’s land and oceans, due to plate tectonics, can cause changes in climate over long periods.
For example: Convergence of continents like Asia and India that build mountains cool global climates by removing CO2 from the atmosphere (For further details check out chapter 21.3 in your textbook)

16. 2. Earth’s orbital motions
Changes in the shape of the Earth’s orbit and the tilt of Earth’s axis of rotation affect global time scales.
Our eccentric orbit brings us closer to and further away from the sun during our revolution. When closer to the sun Earth’s global climate is warmer.
Earth’s wobble on our axis can change by 3°, causing more severe seasons. When the axis is less tilted, the temperature difference between summer and winter is less.

17. 3. Ocean Circulation
Changes in ocean circulation caused by El Nino can also result in short term climate shifts.
El Niño is associated with a band of warm ocean water temperatures that periodically develops off the Pacific coast of South America.
For example, some areas that are normally dry and arid receive large amounts of rain during El Nino.

18. 4. Solar Activity
An increase in sunspots appears to correspond with warm periods in Europe and North America. When sunspots occur, more solar energy is being released by the sun.
So it is no surprise that a decrease in sunspots has been shown to correlate with cooler periods.

19. 5. Volcanic Eruptions
Volcanic ash, dust, and sulfur based aerosols in the air increase the amount of solar radiation that is reflected back into space. This causes the Earth’s lower atmosphere to cool on a short-term geologic time scale.
Over longer time scales, volcanic eruptions can raise global temperatures by adding gases like CO2 to the atmosphere, increasing the warming caused by the greenhouse effect.

20. Anthropogenic Factors
These are factors that result from the influence of human beings on nature.
What are human’s impact on climate?

21. On your own – turn to text book pages 606- 607 and complete the inquiry lab

22. The greenhouse effect is a natural warming of both the Earth’s lower atmosphere and Earth’s surface.
Major Gases involved:
water vapor, methane, and carbon dioxide
Without these greenhouse gases, Earth would be much too cold to support most types of life that exist on Earth.
So why are humans so worried?

23. Data
Studies indicate that human activities for the past 200 years or so have strengthened the greenhouse effect.
Since 1850, CO2 levels have risen at an alarming rate.
Most of the CO2 has been added by the burning of fossil fuels, and deforestation.

24. The result Global climate change
As a result of increase in carbon dioxide levels, as well as other greenhouse gases, global atmospheric temperatures have increased.
The term global warming is used to refer specifically to the increase in temperature of Earth’s atmosphere near the surface.
During the 20th century, Earth’s average surface temperature increase by about 1.0°C
Scientists predict that temperatures on Earth will continue to increase in the 21st century.