NOTE: This presentation was not made for public use. Please do not use this presentation without my permission and the permission of each of the authors of the photographs, quotes, and other materials that they contain. Thank you, Vicki Hughes Labs, Activities, and WS for this presentation: Earth 2100

Climate Changes (ACT L51) Arctic Ocean sea ice coverage has shrunk to the lowest level since modern records began, smashing the previous record by 760,000 square kilometers (293,000 square miles). National Snow and Ice Data Center CrashCourse Ice Age

Ice Ages Ice age = long period of climatic cooling during which continental ice sheets cover large areas of Earth’s surface.

Ice Ages Begins with a long-term decrease in average temperatures.

Ice Ages Drop of 5 o C with increased snowfall = ice age

Ice Ages Glacial period = time during which ice sheets are advancing

Ice Ages Last glacial period 1/3 of Earth was covered in glaciers Mostly North America and Eurasia Sea level was 140 m lower than today

Ice Ages Causes of Ice Ages Milankovitch Theory 1. Changes in Earth’s orbit about every 100,000 years.

Ice Ages Causes of Ice Ages Milankovitch Theory 2. Earth’s tilt varies from 21.5 to 24.5 over about 41,000 years.

Ice Ages Causes of Ice Ages Milankovitch Theory 3. Earth’s precession makes a complete circle every 26,000 years.

Ice Ages Causes of Ice Ages All theories state that the amount of solar energy reaching the Earth’s surface decreases.

Climate Change Temperature has increased 1.53 o F Human Impact

Natural Climate Change Ocean pH has dropped 0.01 pH points. Human Impact When carbon dioxide dissolves in the ocean, carbonic acid is formed.

Natural Climate Change Human Impact Sea level has risen 0.14 inches per year since the early 1990s.

Ozone Depletion CFCs (ChloroFluoroCarbons) Ozone occurs naturally in the atmosphere. Natural ozone protects the Earth from solar ultraviolet rays. Ozone occurs naturally in the atmosphere. Natural ozone protects the Earth from solar ultraviolet rays.

Noticed first in the late 1970s Steady decline of about 4% per decade Noticed first in the late 1970s Steady decline of about 4% per decade TOMS ozone

Global Warming and Hydrocarbons Hydrocarbons are the chemicals that make up fossil fuels like gasoline and oil. CrashCourse Climate Change

IPCC Intergovernmental Panel on Climate Change What is the IPCC? Headquarters in Geneva, Switzerland Assigned by the United Nations to study and report on climate change 772 top climate scientists from 195 countries IPCC was awarded the Nobel Peace Prize

Pine Island Glacier, Antarctica 2014 Evidence of Climate Change Greenland Ice Melt Permafrost Melting and Methane Release Disappearing Islands

In the Southeast USA: Since 1970, average annual temperatures in the region have increased by about 2°F. The average number of freezing days has declined by four to seven days per year since the mid-1970s.

Low emission scenarioHigh emission scenario In the Southeast USA: Projected temperature increase by 4 to 9°F by More frequent and more severe hurricanes. Florida will experience less rainfall outside of storms.

Ocean acidification = decrease in ocean pH caused by excess CO 2 turning to carbonic acid in the water.

Why the IPCC thinks we are experiencing global warming: Indications of global warming: 1. More Severe Storms

Facts about Global Warming 2. Increasing global temperatures

Facts about Global Warming 3. Melting Ice Bodies

Facts about Global Warming 4. Droughts

Facts about Global Warming 5. Rising Sea Levels

Facts about Global Warming 5. Melting Permafrost

Facts about Global Warming 5. Melting Permafrost and Release of Methane Permafrost layer with methane trapped in ice.Melted layer with methane released from ice.

The direct relationship between warming and hydrocarbons.

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