Climate changes  Earth is constantly changing, including the climate. Natural processes Human impacts

Climate Change  Ice Ages-Periods of extensive glacial cover The last ice age ended about 10,000 years ago (Pleistocene) Ice ages have occurred due to changes in Earth’s tilt/axis

Volcanic eruptions  Volcanoes release large amounts of gas and ashes  Clouds can block out the sun’s radiation and cause a cooling of Earth (Year With No Summer)

El Niño  El Niño – Is a period where the Eastern Pacific Ocean gets warmer while the Western Pacific gets cooler Trade winds delivering warm water to the west die down The Eastern Pacific Ocean will have a pressure decrease  More rainfall The Western Pacific Ocean will have a pressure increase  Less rainfall

La Niña  La Niña – Period where temperatures in the Eastern Pacific Ocean cool down Caused when Trade Winds strengthen blowing warm water to the west causing cold water to pile up in the East The Eastern Pacific Ocean will have a pressure increase  Less rainfall The Western Pacific Ocean will have a pressure decrease  More rainfall

Solar Activity  When the sun is most active – contains sunspots (dark spots) on the sun (more solar radiation)  Increase in number of sun spots – temperatures in North America and Europe increase

Short Term Changes In Climate  Seasons are short term periods of climate change Exist because Earth is tilted on its axis Some areas of the world get more direct heat

Causes of Climate Change  Changes in Earth’s Orbit Every 100,000 years Earth’s orbit becomes more elliptical Changes in Earth’s Axis- Every 41,000 years Earth’s tilt changes from 22.1 degrees to 24.5 degrees

Sea Level  Sea level has fluctuated through Earth’s History. Global Warming activists often point rises in sea level as evidence However shifts in tectonic plates can cause a rise in sea level

Identifying P-S-T  Identify: Purpose---Why is the author writing this exercise? Scope----What are the range of ideas explored and addressed in this article? Topic-----What is the main idea addressed in this article? What point is the author trying to make?