LONG-TERMCHANGES IN CLIMATE

STUDYING CLIMATE CHANGE

In studying ancient climates, scientists follow an important principal: If plants or and animals need certain conditions to live in, then similar plants and animals in the past also required those conditions.

3 WAYS SCIENTISTS STUDY CLIMATE CHANGE

1- Fossil Records2- Tree Rings3- Pollen Records

1- Fossil RecordsFossils of plants or animals do not

match the current climate.

2- Tree RingsThickness of the tree ring indicates the climate. (A thin ring- dry or cool, and a wide ring- warm or wet)

3- Pollen RecordsPollen records (buried under layers of mud) indicate the types of plants that

grew in an area thousands of years before.

ICE AGES During each ice age, huge sheets of ice called

glaciers covered large parts of the Earth’s surface.

Interglacial Periods- the warm period of time between ice ages

Last Ice Age- Ended about 10,500 years ago Next Ice Age- 90,000 years? 490,000? Maybe?

CAUSES OF CLIMATE CHANGE

Earth’s Position- to the sun (orbit) or the tilt of the Earth

Solar Energy- the amount of energy from the sun

Movement of the Continents- about 225 million years ago Pangaea broke apart and the continents moved to their present positions

CHECKPOINT QUESTIONWhy were the oceans lower during the ice

ages?Much of the water on Earth was frozen in

ice sheets that covered the land.

WHAT NORTH AMERICA MAY LOOK LIKE IF ALL OF THE POLAR ICE MELTS.

INTERPRETING MAPS Which present-day continents broke

away from Gondwanaland?South AmericaAfricaAntarcticaAustraliaIndia