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Global Warming
by Alex Kiss
Natural Warmth
The Earth’s surface is heated primarily by
sunlight
 It radiates long wavelength photons of
Infrared (IR)
 Certain “greenhouse” gases trap some
escaping radiation, exciting them to
vibrate and rotate, effectively heating the
air. Examples: CO2, CH4, N2O, O3, H2O

Consequences
Without this natural “greenhouse effect”
acting as a blanket, temperatures near the
surface would be around -18°C (0°F)
 Instead the average is 15°C (59°F), which
is warm enough to assure a liquid ocean
and conditions suitable for life

Pollution

Since the Industrial Revolution, atmospheric
concentrations of naturally occurring greenhouse
gases:
– Carbon dioxide has increased by 30%
– Methane has more than doubled
– Nitrous oxide has risen by more than 15%

Hydrofluorocarbons (HFCs), perfluorocarbons
(PFCs), and sulfur hexafluoride (SF6), are
unnatural and highly effective greenhouse gases
generated in a variety of industrial processes.
Where Do They Come From?
Combustion of fossil fuels to run cars and trucks, heat
homes and businesses, and power factories
contributes to:
– 98% of U.S. carbon dioxide emissions
– 24% of methane emissions
– 18% of nitrous oxide emissions
 Methane is emitted during the production and
transport of coal, natural gas, and oil, from the
decomposition of organic wastes in landfills, and from
the raising of livestock.
 Nitrous oxide is emitted during industrial and
agricultural activities as well as the combustion of
solid wastes and fossil fuels.

Climate Change
Average global surface temperature has
increased 0.5-1.0% since the end of the 19th
century.
 The 20th century’s 10 warmest years occurred in
the last 15 years of the century, 1998 being the
warmest.
 Snow cover in the northern hemisphere and
floating ice in the Arctic Ocean have decreased.
 Globally, sea level has risen 4-8 inches over the
last century

Future Predictions
Increasing concentrations of greenhouse gases
are likely to accelerate the rate of climate
change.
 Scientists believe average global surface
temperatures could rise by 2.2-10°F in the next
century.
 Evaporation will increase in the next century,
increasing average global precipitation. Also,
Intense rainstorms are likely to become more
frequent.
 Sea level is likely to rise two feet along most of
the U.S coast.
