Global Warming

Root Words

History of Earth’s Climate Earth formed ~4.6 billion years ago Originally very hot Sun’s energy output only 70% of present Liquid water present ~4.3 billion years This is a big picture examination of the earth’s climate  The Earth was formed around 4.6 billion years ago  And was originally very hot  However, the Sun’s energy output was only 70% of what it is presently  Liquid water was present on the surface around 4.3 billion years ago

History of Earth’s Climate Life appeared ~3.8 billion years ago Photosynthesis began 3.5-2.5 billion years ago Earth began cycles of glacial and interglacial periods ~3 million years ago The first life forms appeared ~3.8 billion years ago  Photosynthesis began 3.5-2.5 billion years ago,  which produced oxygen and removed carbon dioxide and methane, which are greenhouse gases, from the atmosphere  As a result, the Earth went through periods of cooling, commonly referred to as “Snowball Earth” and subsequent warming  Earth began its current cycles of glacial and interglacial periods around 3 million years ago 

Earth’s Temperature Solar Energy Solar Energy Sun The temperature of the earth is directly related to the energy input from the Sun.  Some of the Sun’s energy is reflected by clouds.  Other is reflected by ice. The remainder is absorbed by the earth. 

Earth’s Temperature Solar Energy Radiation Cooling Sun  If amount of solar energy absorbed by the earth is equal to the amount radiated back into space, the earth remains at a constant temperature. 

Solar Energy Earth’s Temperature Sun Radiation Cooling  However, if the amount of solar energy is greater than the amount radiated, then the earth heats up. 

Radiation Cooling Earth’s Temperature Sun Solar Energy  If the amount of solar energy is less than the amount radiated, then the earth cools down. 

Sun Greenhouse Effect To a certain degree, the earth acts like a greenhouse.  Energy from the Sun penetrates the glass of a greenhouse and warms the air and objects within the greenhouse. The same glass slows the heat from escaping, resulting in much higher temperatures within the greenhouse than outside it. 

Earth’s Atmospheric Gases Nitrogen (N2) Non- Greenhouse Gases 99% Oxygen (O2) Water (H2O) Greenhouse Gases 1% Likewise, the earth’s atmospheric gases affect the ability of the earth to radiate the Sun’s energy back into space.  Nitrogen and  Oxygen  make up 99% of the earth’s atmospheric gases  and are non-greenhouse gases.  Water,  Carbon Dioxide,  and Methane  make up 1% of the earth’s atmosphere,  but are greenhouse gases, since they cause the earth to retain heat.  Carbon Dioxide (CO2) Methane (CH4)

These greenhouse gases last a long time… The U.S. emits about 6.4 billion metric tons of greenhouse gases annually, 25% of the world’s total. 6.4 billion metric tons CO2/yr These greenhouse gases last a long time… Carbon dioxide stays in the atmosphere for approximately 100 years, methane lasts about 12 years. Other greenhouse gases last even longer. Warming begets more warming… As these gases continue to raise surface temperatures, they trigger the release of even greater quantities of carbon dioxide and methane that are currently trapped in frozen Arctic permafrost and tundra soils, further increasing temperatures. A feedback mechanism ensues… …potentially causing “runaway global warming”.

Worldwide Carbon Emissions 8 Liquid fuel Total Gas fuel Solid fuel 7 6 5 Carbon (109 metric tons) 4 3 This spike is due to the exponential increase in the use of fossil fuels over the last 150 years. Shown here are emissions of carbon from  gas,  solid,  liquid fuels, and  the total carbon emissions.  2 1 1750 1800 1850 1900 1950 2000 Year

Annual Carbon Emissions 8 Annual carbon emissions Atmospheric CO2 Atmospheric CO2 average 6 Carbon (109 metric tons) 4 Despite this rapid increase in  carbon emissions, only about  half the carbon can be detected in the atmosphere. The remainder of the carbon dioxide is being dissolved in the oceans or incorporated into trees.  2 1955 1965 1975 1985 1995 2005 Year

Future Carbon Dioxide Levels Increasing CO2 Likely to double within 150 years: Increased coal usage Increased natural gas usage Decreased petroleum usage (increased cost and decreasing supply) Future Carbon Emissions  will probably increase, especially in China and developing countries  This will result in a likely doubling of carbon dioxide levels within 150 years, due to  Increased coal usage  And increased natural gas usage,  although petroleum usage is likely to decrease due to increased cost and decreasing supply 

40 % Households are Big Contributors to Climate Change Of all U.S. greenhouse gas emissions come from households: Vehicles Home Heating Electricity 40 %

So how can each of us slow global warming now?

Reduce our consumption of fossil fuels Because greenhouse gas emissions are tied very closely to our energy consumption, using less fossil fuel based energy puts fewer greenhouse gases into the atmosphere. This will help slow global warming. Mountaintop removal for coal mining near Rawl, West Virginia. 50% of electricity in the United States is produced from coal. (