Climate Change and Ozone Loss G. Tyler Miller’s Living in the Environment 14 th Edition Chapter 21 G. Tyler Miller’s Living in the Environment 14 th Edition Chapter 21

Key Concepts  Changes in Earth’s climate over time  Factors affecting climate  Possible effects of global warming  Adapting to climate change  Human impacts on the ozone layer  Protecting and restoring the ozone layer

Average temperature over past 900,000 years Thousands of years ago Average surface temperature (°C) Present Past Climate Changes

Temperature change over past 22,000 years Years ago Temperature change (°C) 20,00010,0002,0001, Now End of last ice age Agriculture established Average temperature over past 10,000 years = 15°C (59°F) Past Climate Changes

Temperature change over past 1,000 years Year Temperature change (°C)

Average temperature over past 130 years Year Average surface temperature (°C) Recent trends in global temperatures

IPCC 1988 UN and the World Meteorological Organization established the (IPCC) Intergovernmental Panel on Climate Change to document past climate change and project future climate change. A network of over 2,000 leading climate experts from 70 nations.

Table 21-1 Page 464 Table 21-1 Major Greenhouse Gases from Human Activities Greenhouse Gas Carbon dioxide (CO2) Methane (CH4) Nitrous oxide (N2O) Chlorofluorocarbons (CFCs)* Hydrochloro- fluorocarbons (HCFCs) Hydrofluorocarbons (HFCs) Halons Carbon tetrachloride Average Time in the Troposphere 100–120 years 12–18 years 114–120 years 11–20 years (65–110 years in stratosphere) 9–390 15– Human Sources Fossil fuel burning, especially coal (70– 75%), deforestation, and plant burning Rice paddies, guts of cattle and termites, landfills, coal production, coal seams, and natural gas leaks from oil and gas production and pipelines Fossil fuel burning, fertilizers, livestock wastes, and nylon production Air conditioners, refrigerators, plastic foams Fire extinguishers Cleaning solvent Relative Warming Potential (compared to CO 2 ) –8, –2, –12,700 5,500 1,400

The Greenhouse Effect Fig p. 110

Climate Change and Human Activities  Increased use of fossil fuels  Deforestation  Global warming  Melting icecaps and glaciers  Rising sea level

Global Warming Svante Arrhenius first speculated in 19 th century Current Causes Deforestation Greenhouse Gas Levels Burning of Fossil Fuels Main villain is currently Carbon Dioxide (CO 2 )

Deforestation

Deforestation - US About one half of the forests that covered the Earth are gone Since 1600, 90% of the U.S. forests have been cleared away

Deforestation - Rainforests One football field of rainforest is lost every 1.4 seconds

Results of Deforestation Loss of trees’ ability to remove CO 2 Decaying trees release CO 2 and methane 25% of global GHG emissions Fallen trees are often burnt which releases CO 2 Accounts for 20% of global CO 2 emissions Deforestation the largest source of emissions in developing countries

Greenhouse Effect

Certain gases in the Earth’s atmosphere trap energy from the sun carbon dioxide – water vapor methane – nitrous oxide Without these gases, the Earth’s average temperature would be about 60ºF colder Greenhouse Gases These gases are Greenhouse Gases

Global Warming

Evidence CO 2 and Temperature

Five Warmest Years on Record Since 1980, the Earth has experienced 19 of its 20 hottest years on record

Evidence CO 2 and TemperatureGlaciers

Portage Glacier- near Anchorage Alaska- 1950/2001

Rhone glacier in the Kanton of Valais, Switzerland 1859 / 2001

Grinnell glacier, Glacier National Park, USA 1911 / 2000

Glacier Ururashraju, at about 15,000 feet in Cordillera Blanca of Peru 1986 / 1999

2004

Glaciers Have been shrinking throughout the 20th Century Loss of glaciers in South America and Asia glaciers is particularly rapid and will threaten the water supplies of millions of people

Evidence CO 2 and Temperature Glaciers Polar Ice Arctic Antarctic Greenland

Arctic Ice

Perennial ice may be 10 or more feet thick New ice is only one to seven feet thick Since 1970  10% loss of ice cover per decade

Albedo Effect

Albedo, or reflectivity Fig p. 480

NASA Sees Rapid Changes in Arctic Sea Ice NEWS RELEASE: September 13, 2006 From 1970 until 2000 there was a 10 percent decrease in Arctic perennial sea ice every decade 14 percent Between 2004 and 2005 the ice shrunk abruptly by 14 percent

Permafrost

Permafrost Where soil over 1-meter down never thaws About 10% of Earth’s surface has permafrost Tundra and taiga are characterized by extreme cold 24 hours of sun during the summer Huge amount of vegetation grows In the last 11,000 years, the permafrost has not thawed None of the vegetation has decayed Decay releases CO 2 and methane

Permafrost Alaska permafrost temperature has increased 0.5° to 1.5° C since 1980, Serious effects include forest damage sinking roads and buildings eroding tundra riverbanks changes in tundra vegetation increased carbon dioxide and methane emissions from thawed peat.

Permafrost Estimates of billions of tons of methane Double existing methane in atmosphere Methane is 20 to 60 times as strong of a greenhouse gas as CO 2 10 to 25% increase in global warming

Antarctic Ice

Antartica Land mass covered by multiple glaciers Glaciers average 8000 feet thick Represents 10% of all landmass on Earth

Moulins Rivers of water about 10 meters in diameter that flow through the glacier Bring melted water below the glaciers

Series of Moulins

Antarctica Melting If all of the ice in the glaciers of Antarctica melt the oceans will rise 200 feet

Greenland Ice

Greenland Ice Melt Glaciers located on three islands Greenland loses 20% more ice than it gains each year If all of the ice melts – oceans will rise 23 feet If moulins work like those in Antarctica…

Evidence CO 2 and Temperature Glaciers Polar Ice Arctic Antarctic Greenland Weather Severity

Droughts The national drought was one of the three most extensive droughts in the last 40 years In 2002, the Western United States experienced its second worst wildfire season in the last 50 years; more than 7 million acres burned The period from April through June of 1998 was the driest three-month period in 104 years in Florida, Texas, and Louisiana

Evidence CO 2 and Temperature Glaciers Polar Ice Arctic Antarctic Greenland Weather Severity Biome Changes

Oceans absorb CO 2 CO 2 in water makes Carbonic Acid Increased CO 2 especially in cold water As cold deep ocean currents (abyssal) resurface they are release CO 2 Greater acidity of oceans is one of the factors that effect bleaching coral