Climate Change

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)

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

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

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

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

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

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

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

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?

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

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.

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?

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)

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

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.

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

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

Carbon Dioxide (CO2) CO2 is a greenhouse gas. Sources of CO2 are: Volcanoes Forest Fires Factories & Cars (Burning of Fossil Fuels) Other Natural Sources

Insolation Insolation is the amount of energy from the Sun reaching the Earth. The solar energy is measured in watts per square meter (W/m2). Insolation is dependent on the changes of the Earth’s orbit (Eccentricity, Tilt, and Precession).

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

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

Changes in the Earth’s Orbit : Precession 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.

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

Biodiversity Number and variety of species on Earth.

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