Chapter 13: Earth’s Atmosphere and Climate Big Question Global Warming Is Happening: What Part Do We Play?

Lesson 13 / ESRM 100 / University of Washington Is the Global Temperature Rising? Yes, and it is rising globally. Has the temperature risen steadily?

Lesson 13 / ESRM 100 / University of Washington What Causes Climate Change and What Is Making It Get Warmer? Studies of ice cores show Earth’s surface temperature has varied over time.

Lesson 13 / ESRM 100 / University of Washington The answer lies in the Earth’s energy balance between the amount of energy coming in from the sun and the amount of energy radiated out by the Earth.

Lesson 13 / ESRM 100 / University of Washington Albedo Albedo: the percentage of light received by a surface that is reflected and scattered

Lesson 13 / ESRM 100 / University of Washington Variation in the Sun’s Energy May Be A Reason for Climate Changes The sun’s energy seems to have varied over the ages. The Little Ice Age lasted from about 1450 to 1850.

Lesson 13 / ESRM 100 / University of Washington Milankovich Cycles: Another Possible Explanation Some temperature cycles stem from Earth’s wobble in an elliptical orbit.

Lesson 13 / ESRM 100 / University of Washington Volcanoes Can Alter Climate Volcanic eruptions cool the climate in two ways: - Atmospheric dust reflects sunlight back into space - Smaller dust particles provide water condensing surfaces, forming clouds

Lesson 13 / ESRM 100 / University of Washington Dust from Our Own Activities Also Cools the Climate Aerosol pollution particles reduce amount of sunlight reaching Earth. Emissions have reduced global warming.

Lesson 13 / ESRM 100 / University of Washington Variations in Ocean Currents May Affect the Climate Ocean currents and prevailing winds warm or cool our planet. The Gulf Stream: a major ocean circulation affecting climate.

Lesson 13 / ESRM 100 / University of Washington El Niño: A Climate Phenomenon Linked to Ocean Currents Source: Available at

Lesson 13 / ESRM 100 / University of Washington The Greenhouse Effect, and How It Warms Earth’s Surface

Lesson 13 / ESRM 100 / University of Washington Greenhouse Gases Are Increasing We are part of the reason. Carbon dioxide has been increasing in the atmosphere for some time.

Lesson 13 / ESRM 100 / University of Washington Would It Really Be So Serious If Earth Warmed Up a Bit?

Lesson 13 / ESRM 100 / University of Washington Computer models are the major scientific tool in step one. Model results: global warming will increase Earth’s surface temperature by 1.5 to 4.5°C from 1990 to 2100.

Lesson 13 / ESRM 100 / University of Washington The Effects of a Rising Sea Level Risen naturally since last ice age. Increases damage from major storms.

Lesson 13 / ESRM 100 / University of Washington Global Warming Affects on World Climate Glaciers are melting while Antarctica’s central ice cap is growing. Change frequency and intensity of storms. Other climate changes include wetter winters, hotter and drier summers, and increased droughts.

Lesson 13 / ESRM 100 / University of Washington Agriculture Global warming may seriously affect world’s food supply. The best agricultural areas may no longer be in North America. Winter snowpacks will store less water.

Lesson 13 / ESRM 100 / University of Washington Lowering of Water Tables and Reservoirs Could cause serious water supply shortages. Water use in some regions is already unsustainable.

Lesson 13 / ESRM 100 / University of Washington Biological and Ecological Changes

Lesson 13 / ESRM 100 / University of Washington Endangered Species What will happen to species that can not migrate nor adapt? Case Study: Kirtland’s warbler: an endangered-species success story

Lesson 13 / ESRM 100 / University of Washington Kirtland’s warblers require a very specific habitat. They nest only in young jack-pine woodlands. To save these birds, 38,000 acres were set aside in Michigan.

Lesson 13 / ESRM 100 / University of Washington Slowing the Temperature Rise Reduce production and release of greenhouse gases. Find ways to sequester (store) greenhouse gases. Actively cool the climate.

Chapter 13: Earth’s Atmosphere and Climate Questions? your TA.