Predicting Past Climates

Huzaifa and Shajee

We will talk about: Predicting Past Climates:

Ice Cores Record temperature data by trapping

gases such as oxygen, carbon dioxide, methane, and nitrous oxide

Dentrochronology Tree rings and coral reefs grow annual

layers in proportion to how favourable climate is.

Rocks, Oceans, and Caves Sediment may contain evidence such as

fossils and plant pollen, of past climates.

Studying Clues to Past Climates: Scientist have recorded temperature, rainfall, and

other data over the last 200 years Before people kept climate records in:

Journals Paintings Farming Records Oral Histories

People who study past climates are called Paleoclimatologists.

Proxy record: stores of information in tree rings, ice cores, and fossils that can be measured to give clues on what the weather was like in the past.

Ice Cores

What are Ice Cores: A core sample from the build up of snow and

ice They have recrystallized and have trapped air

bubbles from previous time periods They Contain:

Ice Snow Wind blown dust Ash Bubbles of atmospheric gas Radioactive substances

What are Ice Cores: Typical ice cores are removed from ice sheets Most commonly from the polar ice caps of

Antarctica, Greenland, and from high mountain glaciers.

Structure: Mostly formed from snow It is a firm grainy material with

texture similar to sugar. Age depends of thickness Portions of Antarctica are said to

be covered with ice for more than 20 million years

Scientists don’t to retrieve cores more than one million years old.

What do Ice Cores do: Ice cores increase the levels of CO2 in the

atmosphere The concentration continuously has been

going up and down through out the millenniums.

Ice cores also change the temperature The temperature has been changing more

constantly today, than it was 400 million years ago.

Give information on weather, precipitation, and volcanic eruptions.

Dentrochronology

What is Dentrochronology:

Study of: Tree Rings

Wider in good growing years Narrower in bad growing years

Coral Reefs Grow near the surface of the ocean Layers of coral grow at different in warm

and cold weather

Tree Rings: Trees crate one growth ring per year In warm conditions, they produce a thick ring In cold conditions, a narrow ring Some trees live for thousands of years They are:

Bristle cone pine California Redwood

Clues are assembled from both dead and living trees

They collect records going as far back as 10,000 years

In Ontario, trees have provided proxy climate data for the past 2767 years.

Bristlecone

Pine

California

Redwood

Thicker

Narrower

Coral Reefs: Records are also preserved in coral reefs

Corals add a layer of growth each season

Scientist study them by drilling cylinders of coral and studying their layers

Information from corals, helps determine the water temperature.

Rocks, Oceans, and Caves

Rocks: Layers of soil and rock build up on the earths surface

over time. Each layer may contain clues such as:

Plant Pollen Fossils

Fossils of pollen grains can be used to identify the plants that grew thousand of years previously.

Palynologists: Scientist who study Pollen. They use the:

Size Shape Presence of:

Pores Furrows Air sacs

to Identify the species of the plants

Oceans: Layers of sediment drift to the ocean floor and

form layers of rock Scientist drill cores of sediment from the ocean

floor Fossils of marine plants and animals are found

sometimes Sometimes they are found in colder water than

they lived in This is evidence that the layer containing these

fossil fuels formed during a warmer climate This has allowed scientist to build a picture of the

earth's climate thousand years past.

Caves: Rock formations grow as the minerals that

are dissolved in dripping water solidify into rock.

Scientists can measure and date layers from these rocks

Rock formations grow faster in rainy water Analysis of the layers determine how much

precipitation occurred at specific times in the past.

Quiz Time

1.) What are Proxy Records?

a) Stores of information in tree rings and ice cores

b) Stores of information in tree rings and ice cores, and fossils

c) Stores of information in rocksd) Stores of information in

Dentrochronology

2.)In Ontario, trees have provided

proxy climate data for the past _____ Years

a) 2267

b) 2676

c) 2767

d) 10,000

3.)Tree rings are wider in good growing Years:

a) True

b) False

4.) Which tree can live for thousands of years?

a) Pine

b) Bristlecone Pine

c) Maple

d) Mahogany

5.) Scientists who study pollen are called ________.

a) Palynologistsb) Balneologists c) Pollen Scientistsd) Apologists

The End