STUDYIN

G PAST

CLIMATE

S

STUDYING CLIMATE IN THE PASTPaleoclimatologists study past climates

They use Proxy records; which are stores of information in tree rings, ice cores and fossils that can be measured to give clues to what the climate was like in the past

ICE CORESIce in Greenland and Antarctica contains air

bubbles that have been trapped for thousands of centuries

Scientists drill deep into the ice and extract long cylinders of ice

The ice at the top of the ice core is recent and the bottom ice can be up to 800 000 years old

ICE CORESScientist cut ice cores into very thin

slices and test the air bubbles in each slice for various gases

This measures the amount of carbon dioxide, methane and nitrous oxide that was in the air when the bubble formed

Ice cores have shown scientists that the concentration of these greenhouse gases has changed dramatically over Earth’s history

ICE CORESScientists can also obtain information about the

earth’s temperature, precipitation and volcanic eruptions through preserved layers of dust in an ice core

Ice cores tell scientists that the earth’s climate has gone through many changes in climate (including warmer and colder periods)

TREE RINGS When a tree grows, it creates one growth ring per

year

The rings are the thickest during the years of good growing conditions

Some trees live for thousands of years and scientists can assemble clues from living and dead trees about the climate during that time

CORAL REEFSLike trees, coral reefs add layers of growth each

season

Scientists drill cylinders of coral and study their layers

Information from coral layers help determine the temperature of the surface ocean water when each layer was growing

ROCK, CAVES AND OCEAN SEDIMENTLayers of soil and rock build up on the earth over

time and each layer gives clues, such as plant or fossils to the climate at that time

Sediment cores from the ocean floor contain clues that provide data about past climates

SUMMARYProxy records are indirect records of

past climates contained in natural materials

Analyzing air bubbles in ice cores provides data on greenhouse gases temperature from the past

Analyzing the growth rings on ancient trees and coral provides data on temperature and precipitation from the past