EarthEarth’’s climate and how it s climate and how it changeschanges

• Latitude – distance north or south of equator

• Elevation – height above sea level

• Topography – features on land

• Water Bodies – lakes and oceans

• Atmospheric Circulation – global winds

• Vegetation – type and amount of plants

What Factors Affect Climate?What Factors Affect Climate?

LATITUDELATITUDESun strikes Earth’s surface at different

angles creates variations in climate

Temperate zones

Hot summers and cold winters, 23.5o to 66.5o

north and south of equator

Tropical zonesWarm all year, 23.5o north

to 23.5o south of equator

Climate ZonesClimate ZonesDifferences in solar energy create climate zones

Polar zonesCold all year, 66.5o north

and south to the poles

• Less solar energy is transferred into atmosphere in polar regions than in tropics

• Differences in energy affects weather and climate

• Pressure differences produce winds– Affects evaporation rates, cloud formation, air

masses, and storms

Energy TransferEnergy Transfer

ELEVATIONELEVATION

Mt. Whitney and the Owens Valley, Eastern California

• Elevation increases, temperature decreases• approximately -6.5oC

every 1000 meters or -44oF every 3,281 feet

• Elevation also determines the amount of precipitation

answer: How does elevation affect temperatures and precipitation? Why?

Think:Think: Can you name a mountain range with a Rain Shadow Can you name a mountain range with a Rain Shadow Effect ? Effect ?

• Humid air moves up a mountain: cools, forms clouds, then precipitates

• Moisture is lost, very dry on other side

TOPOGRAPHYTOPOGRAPHYCan create a Rain Shadow Effect

Temperature of water influences atmosphere above it. Water has a higher heat capacity than land.

WATER BODIES AND ATMOSPHERIC CIRCULATIONWATER BODIES AND ATMOSPHERIC CIRCULATION

Global winds distribute heat and moisture around Earth

Look up the term heat capacity

VEGETATIONVEGETATION• Temperature – vegetation influences how much of sun’s

energy is absorbed and released

• Precipitation - plants release water vapor and particles into the air creating clouds (the more plants the more humid it is).

ConsiderConsider: how do you think cutting down the rain forest in : how do you think cutting down the rain forest in Brazil has affected the climate there?Brazil has affected the climate there?

Earth’s Orbital Motion

• Changes in the shape of Earth’s orbit and the tilt of its axis affects global climates

•How elliptical the orbit is varies every 100,000 to 400,000 years

•Every 20,000 to 40,000 years the tilt of the axis changes about 3° (less tilt = less difference between

seasons)

Notice: how has the Sahara desert changed in the last 8,000 years?

Solar Activity

• Over a short time scale: changes in the amount of solar radiation change global climate.

•More sun spots indicate a warmer sun that causes warming periods on Earth

• Fewer sun spots occurred in the 1600’s during the “little ice age” in Europe.

Volcanic Eruptions

• In the short term volcanic eruptions cause cooling from ash, dust and sulfur- containing particles reflecting sunlight back into space (aerosols).

• In the long term it can cause warming by increasing CO2 levels

The Greenhouse Effect

• The Greenhouse Effect is the warming of the atmosphere by gasses that trap solar radiation.

• Water vapor, CO2, and methane are the major greenhouse gasses

Consider: how would increasing methane levels in the atmosphere affect the Earth’s temperature?

Summary

•Write a 5-8 sentence summary of the factors that affect climate and climate change.