A ppt on Global warming..

Download A ppt on Global warming..

Post on 11-Jul-2015




1 download


Slide 1

Global Warming how it is caused and what we should do about it1IntroductionIs the world getting warmer?If so, are the actions of mankind to blame for earths temperature increases?What can/should be done about these issues?2In examining global warming, we will be looking at questions such as Is the world getting warmer? If so, are the actions of mankind to blame for earths temperature increases? What can or should be done about global warming? Are the potential resolutions to global warming worth the cost to implement them? History of Earths ClimateEarth formed ~4.6 billion years agoOriginally very hotSuns energy output only 70% of presentLiquid water present ~4.3 billion years3This is a big picture examination of the earths climate The Earth was formed around 4.6 billion years ago And was originally very hot However, the Suns energy output was only 70% of what it is presently Liquid water was present on the surface around 4.3 billion years agoHistory of Earths ClimateLife appeared ~3.8 billion years agoPhotosynthesis began 3.5-2.5 billion years agoProduced oxygen and removed carbon dioxide and methane (greenhouse gases)Earth went through periods of cooling (Snowball Earth) and warmingEarth began cycles of glacial and interglacial periods ~3 million years ago4The 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 Sun

Earths TemperatureSolarEnergySolarEnergy5The temperature of the earth is directly related to the energy input from the Sun. Some of the Suns energy is reflected by clouds. Other is reflected by ice. The remainder is absorbed by the earth. Sun

Earths TemperatureSolarEnergyRadiationCoolingradiation=absorptionConstant temperature6 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. Sun

Earths TemperatureSolarEnergyRadiationCooling

AbsorptionAbsorptionjCools down8 If the amount of solar energy is less than the amount radiated, then the earth cools down. Greenhouse EffectSUNTo 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.

9How different greenhouse gases are mixing into the atmosphere Earths Atmospheric GasesNitrogen (N2)Oxygen (O2)Water (H2O)Carbon Dioxide (CO2)Methane (CH4)Non-GreenhouseGases99%GreenhouseGases1%11Likewise, the earths atmospheric gases affect the ability of the earth to radiate the Suns energy back into space. Nitrogen and Oxygen make up 99% of the earths atmospheric gases and are non-greenhouse gases. Water, Carbon Dioxide, and Methane make up 1% of the earths atmosphere, but are greenhouse gases, since they cause the earth to retain heat. The U.S. emits about 6.4 billion metric tons of greenhouse gases annually, 25% of the worlds total.Carbon dioxide stays in the atmosphere for approximately 100 years, methane lasts about 12 years. Other greenhouse gases last even longer.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.potentially causing runaway global warming.

6.4 billion metric tons CO2/yrThese greenhouse gases last a long timeWarming begets more warmingA feedback mechanism ensues

12Worldwide Carbon EmissionsCarbon (109 metric tons)012345678175018001850190019502000YearLiquid fuelTotalGas fuelSolid fuel13This 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. Annual Carbon EmissionsAnnual carbon emissionsAtmospheric CO2Atmospheric CO2 average19551965197519851995200504682YearCarbon (109 metric tons)14Despite 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. So how can each of us slow global warming now??15Because 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.

Reduce our consumption of fossil fuels

Mountaintop removal for coal mining near Rawl, West Virginia.

50% of electricity in the United States is produced from coal.(

16 We can make some simple substitutions Replacing just 1 incandescent light bulb with 1 compact florescent bulb saves about 150 pounds of carbon dioxide per year!If every American household replaced just 5 high-use incandescent bulbs with compact florescent lights we'd collectively save more than $8 billion each year in energy costs and we would prevent the greenhouse gases equivalent to the emissions from nearly 10 million cars.

Source: http://www.energystar.gov17Small changes really add upReplace your old refrigerator with a new Energy Star: Annual savings: $90; 700 pounds CO2

Set your thermostat down a few degrees in the winterAnnual savings: $135; 1400 pounds CO2

Wash clothes in cold water onlyAnnual savings: $70; 500 pounds CO2

Drive JUST 10 fewer miles per weekAnnual savings: $80; 520 pounds CO2

Reduce your garbage by 10% through greater recycling or reduced packagingAnnual savings: 1200 pounds CO2 Caulk and weather-strip around doors and windowsAnnual savings: $80; 650 pounds CO2

18Our take-home message

Each of us must take steps to protect our Earth's climate. 19THANK YOUReferencesWikipediawww.google.com bing,com