SEVENTH GRADEEARTH SCIENCE

Climate and Climate Change

The Big Ideas

What is climate?Why is one climate different from another?How are climates classified?How has climate varied over time?What causes seasons?How does the ocean affect climate?How can human activities affect climate?How are predictions for future climate

change made?

Climate

The long-term average weather conditions that occur in a particular region.

There are many variables that determine an area’s climate.

Latitude

The amount of solar energy that hits the earth’s surface depends on its latitude. Locations near the equator tend to have warmer climates than locations at higher latitudes.

Altitude

Temperature decreases as altitude increases. Locations at higher altitudes will have lower temperatures.

Rain Shadows

Mountains influence climate another way. They are barriers to prevailing winds. This causes unique precipitation patterns called rain shadows. A rain shadow is an area of low rainfall on the downwind slope of a mountain.

Large bodies of water

High specific heat of water causes the climates along the coastlines to remain more constant than those in the middle of a continent.

Remember that specific heat is the amount of energy needed to raise the temperature of 1 kg of material by 1 degree C.

Specific heat of water is six times that of land.Ocean currents also affect climate. The Gulf

Stream is a warm current flowing northward along the east and south coast of the United States. It brings warmer temperatures.

Classifying Climates

Polar climate-cold year round, minimal precipitation

Classifying Climates

Continental climate- warm summers, cold winters, moderate precipitation.

Classifying Climates

Dry Climate- hot summers, cooler winters, low precipitation

Classifying Climates

Tropical climates- warm year round, high precipitation

Classifying Climates

Mild climate- warm summers, mild winters, high precipitation, humid

Classifying Climates

Microclimate- a localized climate that is different than the climate of the surrounding area.

Climate Cycles

Long term cycles- Scientists learn about long climate cycles by studying ice cores drilled from ice layers in glaciers and ice sheets.

Climate Cycles

Fossilized pollen, sediments, and the growth rings on trees are also used to gain information.

Climate Cycles

Ice Ages- cold periods lasting from hundreds to millions of years when glaciers covered most of the earth.

Climate Cycles

Interglacials- the warm periods that occur during the ice ages.

Climate Cycles

Short term cycles- these are seasonal changes and changes that result from interaction between the ocean and the atmosphere are short term.

Climate Cycles

Seasons- changes in the amount of solar energy received at different latitudes during different times of the year cause seasons

These changes include temperature changes…

Climate Cycles

… as well as length of day and night.

Climate Cycles

Solstices- marks the beginning of summer and winter.

Summer solstice is the longest day of the year.Winter solstice is the shortest day of the year.

Climate Cycles

Equinoxes- mark the beginning of Spring and Fall Both equinoxes have equal amounts of daylight and nighttime

hours.

Climate Cycles

El Nino and the Southern Oscillation – The combined ocean and atmospheric cycle that results in weakened trade winds across the Pacific Ocean.

Climate Cycles

Monsoons- a wind circulation pattern that changes direction with the seasons

Human Impact

Global Warming- the rise in Earth’s average surface temperature during the past 100 years.

Human Impact

Greenhouse gases- gases in the atmosphere that absorb earth’s outgoing infrared radiation.

Human Impact

Deforestation- the large-scale cutting and/or burning of forests.

Human Impact

Aerosols- released when fossil fuels are burned. Aerosols reflect sunlight back into space preventing the sun’s energy from reaching Earth, potentially cooling Earth’s climate

Human Impact

Warmer temps can cause More water to evaporate Increased water vapor, increased precipitation Melting glaciers and ice sheets Melting polar caps More common extreme weather events

Human Impact

Increased populations increase human impact

Human Impact

What can we do?

See this website:

http://www.nature.org/ourinitiatives/urgentissues/global-warming-climate-change/help/tips-from-a-nature-conservancy-scientist.xml