Climate Change 1 Weather vs Climate Weather is

Climate Change 1

Weather vs. Climate • Weather is the atmospheric conditions at a given place at a given time. – Example: On Sunday it was 72 degrees Fahrenheit and mostly sunny in Sacramento. • Climate is the average weather of a place over a long period of time. – Example: Sacramento has hot dry summers and cool wet winters. (Mediterranean climate) 2

Climate • Temperature and precipitation are how we measure climate. • Climate information preserved in the geologic record only tells us about temperature. • We infer precipitation from temperature. – Warmer climates are usually wetter – Colder climates are usually drier 3

Plate Tectonics & Climate • On longer time scales (millions of years) Plate Tectonics play a major role in climate. • Land changes ocean currents • Mountains change wind patterns 4

Plate Tectonics & Climate • Movement of plates + landmasses can close or open new pathways for ocean currents (Isthmus of Panama) 5

Plate Tectonics & Climate • Building or destruction of topography changes global air circulation patterns (Himalayas) 6

Plate Tectonics & Climate • Changing ocean currents and global air circulation patterns can cause major changes to climate. 7

Climate • What do we use to analyze climate? –Ice Cores –Tree rings –Glacier length –Ocean sediments 8

Ice Cores • Ice Cores are pieces of ice that are drilled out of glaciers, ice sheets and shelves 9

Tree Rings • Growth rings form every year. They often reflect the conditions in which the tree grew. • Thicker rings indicate more sun and rain. • What would thinner rings mean? 10

Glacier Length • Longer and larger glaciers mean a colder climate. • Shorter and smaller glaciers mean a warmer climate. 11

Ocean Sediments • Tiny fossil sea animals, called foraminifera are found in the material at the bottom of the ocean. • By analyzing the fossils scientist can determine the temperature of the ocean at the time the sea animal died. 12

Earth’s History • We will use years before present (b. p. ), measured from 1950, to describe Earth’s history. • Using the next slide answer the following: – Which way is time flowing on the diagram? • From Left to Right • From Right to Left – Did modern humans (homo sapiens) live at the same time as sabertooth tigers? – Do wooly mammoths live today? 13

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Average Global Temperature • Average Global Temperature is the average temperature of all locations on the surface of Earth. – Today’s average global temperature is approximately 59° Fahrenheit (14° Celsius) 15

Global Warming • Global Warming is when the Average Global Temperature goes up. 16

Ice Age vs Glaciation • Ice Ages are periods of time when large portions of the Earth’s surface are covered with ice sheets. • Ice Ages last 10 -100’s of millions of years. • Glaciations last 10’s of thousands of years. • We are dealing with glaciations (short ice ages) • The time period between ice ages/glaciations is called an interglacial period. 17

Ice volume • Ice volume is the amount of Ice on the surface of the Earth. – Glaciers – Sea Ice 18

Greenhouse Effect/ Gases • Greenhouse gases trap heat in the Earth’s atmosphere. • This trapping of heat is called the Greenhouse Effect. 19

Carbon Dioxide (CO 2) • CO 2 is a greenhouse gas. • Sources of CO 2 are: – Volcanoes – Forest Fires – Factories & Cars (Burning of Fossil Fuels) – Other Natural Sources 20

Insolation • Insolation is the amount of energy from the Sun reaching the Earth. • The solar energy is measured in watts per square meter (W/m 2). • Insolation is dependent on the changes of the Earth’s orbit (Eccentricity, Tilt, and Precession). 21

Changes in the Earth’s Orbit : Eccentricity Near-circular Orbit = Mild winters but cool summers. Favors Ice Age Eccentric Orbit = Cold winters but hot summers. Favors Interglacial Period 22

Changes in the Earth’s Orbit : Tilt • Small Axis Tilt: Mild winters but cool summers. Favors Ice Age • Large Axis Tilt: Cold winters but hot summers. Favors Interglacial Period 23

Changes in the Earth’s Orbit : Precession is the "wobble" of the Earth's rotational axis. One complete wobble takes 26, 000 years. Precession changes the pole star as seen from Earth. 24

Industrial Revolution • The time period in which machine power replaced human and animal power in the production of goods. 25

Biodiversity • Number and variety of species on Earth. 26

Biome • Area on the Earth with a particular climate. – Desert, rainforest, tundra, boreal forest, grassland, deep oceans, etc. 27