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.