Global WarmingGlobal Warming

by Alex Kissby Alex Kiss

Natural WarmthNatural Warmth

The Earth’s surface is heated primarily The Earth’s surface is heated primarily by sunlightby sunlight

It radiates long wavelength photons of It radiates long wavelength photons of Infrared (IR)Infrared (IR)

Certain “greenhouse” gases trap some Certain “greenhouse” gases trap some escaping radiation, exciting them to escaping radiation, exciting them to vibrate and rotate, effectively heating vibrate and rotate, effectively heating the air. Examples: COthe air. Examples: CO22, CH, CH44, N, N22O, OO, O33, , HH22OO

ConsequencesConsequences

Without this natural “greenhouse Without this natural “greenhouse effect” acting as a blanket, effect” acting as a blanket, temperatures near the surface would temperatures near the surface would be around -18°C (0°F)be around -18°C (0°F)

Instead the average is 15°C (59°F), Instead the average is 15°C (59°F), which is warm enough to assure a which is warm enough to assure a liquid ocean and conditions suitable liquid ocean and conditions suitable for lifefor life

PollutionPollution

Since the Industrial Revolution, atmospheric Since the Industrial Revolution, atmospheric concentrations of naturally occurring concentrations of naturally occurring greenhouse gases:greenhouse gases:– Carbon dioxide has increased by 30%Carbon dioxide has increased by 30%– Methane has more than doubledMethane has more than doubled– Nitrous oxide has risen by more than 15%Nitrous oxide has risen by more than 15%

Hydrofluorocarbons (HFCs), perfluorocarbons Hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF(PFCs), and sulfur hexafluoride (SF66), are ), are unnatural and highly effective greenhouse unnatural and highly effective greenhouse gases generated in a variety of industrial gases generated in a variety of industrial processes.processes.

Where Do They Come From?Where Do They Come From? Combustion of fossil fuels to run cars and Combustion of fossil fuels to run cars and

trucks, heat homes and businesses, and power trucks, heat homes and businesses, and power factories contributes to:factories contributes to:– 98% of U.S. carbon dioxide emissions98% of U.S. carbon dioxide emissions– 24% of methane emissions24% of methane emissions– 18% of nitrous oxide emissions18% of nitrous oxide emissions

Methane is emitted during the production and Methane is emitted during the production and transport of coal, natural gas, and oil, from the transport of coal, natural gas, and oil, from the decomposition of organic wastes in landfills, decomposition of organic wastes in landfills, and from the raising of livestock.and from the raising of livestock.

Nitrous oxide is emitted during industrial and Nitrous oxide is emitted during industrial and agricultural activities as well as the combustion agricultural activities as well as the combustion of solid wastes and fossil fuels.of solid wastes and fossil fuels.

Climate ChangeClimate Change

Average global surface temperature has Average global surface temperature has increased 0.5-1.0% since the end of the increased 0.5-1.0% since the end of the 1919thth century. century.

The 20The 20thth century’s 10 warmest years century’s 10 warmest years occurred in the last 15 years of the occurred in the last 15 years of the century, 1998 being the warmest.century, 1998 being the warmest.

Snow cover in the northern hemisphere Snow cover in the northern hemisphere and floating ice in the Arctic Ocean have and floating ice in the Arctic Ocean have decreased.decreased.

Globally, sea level has risen 4-8 inches Globally, sea level has risen 4-8 inches over the last centuryover the last century

Future PredictionsFuture Predictions Increasing concentrations of greenhouse Increasing concentrations of greenhouse

gases are likely to accelerate the rate of gases are likely to accelerate the rate of climate change.climate change.

Scientists believe average global surface Scientists believe average global surface temperatures could rise by 2.2-10temperatures could rise by 2.2-10°F in the °F in the next century.next century.

Evaporation will increase in the next Evaporation will increase in the next century, increasing average global century, increasing average global precipitation. Also, Intense rainstorms are precipitation. Also, Intense rainstorms are likely to become more frequent.likely to become more frequent.

Sea level is likely to rise two feet along Sea level is likely to rise two feet along most of the U.S coast.most of the U.S coast.