Chapter 13 Section 4 What are local climates? Objective: Describe some factors that affect local climates.

Local Climate Local conditions can affect the climate of any area These conditions result in small climate zones called local climates. Altitude, or distance above sea level, has the greatest effect on local climates.

Local Climate Large lakes and forests also affect local climates. Like oceans, large lakes can warm or cool the temperature of the air. Forests are another factor. They slow down winds and add water vapor to the air. This increases humidity.

IDENTIFY: What are three factors that can affect local climates?

Microclimates Local climates can be broken down into even smaller climate zones called microclimates. Can be as small as a schoolyard. All cities have microclimates. The average temperature in a city is higher by several degrees than it is in surrounding areas. Heavy traffic in cities warms the air and raises average temperatures.

Microclimates The energy used to heat and light buildings also raises the air temperature in cities. The heat absorbed during the day by streets and buildings is radiated back into the air at night.

Microclimates Skyscrapers in cities may act as mountains and change patterns of rainfall. Air pollution and dust from automobile exhaust and also from industrial smokestacks add particles to the air. These extra particles cause more rain to fall over large cities.

2. EXPLAIN: How do skyscrapers affect the climate in cities?

Global Warming Today, human activities may be changing Earth’s climate. Increased pollution may cause temperatures around the world to increase. This pattern of increased temperature is called global warming.

Global Warming Global warming could cause: the polar ice caps to melt and sea levels to rise as much as 60m New York would be almost covered with water Only the tops of very tall buildings would be above the water

3. PREDICT: What would New York City look like if the ice caps melted?

13-4 Classwork What factor affects local climates the most? Is the average temperature in a city lower or higher than that of surrounding areas? Why? Can air pollution affect the amount of rainfall in an area? Explain. What is global warming?

13-4 Classwork 5. HYPOTHOSIZE: Chicago is located in the north central United States. It is on one of the Great Lakes. How does this affect the local climate? 6. INFER: Would you expect a city or its suburbs to get more snow? Explain.