by Anthony Roberts
The earth’s climate is predicted to change because human
activities are altering the chemical composition of the atmosphere through the
buildup of greenhouse gases – primarily carbon dioxide, methane, and nitrous
oxide. The heat trapping property of
these gases is undisputed.
The Greenhouse Effect
Solar radiation passes through the clear atmosphere
Most radiation is absorbed by the earth’s surface and warms
Some solar radiation is reflected by the earth and the
Infrared radiation is emitted form the earth’s surface.
Some of the infrared radiation passes through the atmosphere,
and some is absorbed and re-emitted in all directions by greenhouse gas
molecules. The effect of this is to
warm the earth’s surface and the lower atmosphere.
Energy from the sun drives the earth’s weather and climate,
and heats the earth’s surface; in turn the earth radiates energy back into
space. Atmospheric greenhouse gases
(water vapor; carbon dioxide, and other gases) trap some of the outgoing
energy, retaining heat somewhat like the glass panels of a greenhouse.
The earth’s average temperature is a more hospitable 60
Problems may arise when the atmospheric concentration of
greenhouse gases increases.
Atmospheric concentrations of carbon dioxide have increased
nearly 30% , methane concentrations have more than doubled, and nitrous oxide
concentrations have risen by about 15%.
Fossils fuels burned to run cars and trucks, heat homes and
businesses, and power factories are responsible for about 98% of U.S. carbon
dioxide emissions, 24% of methane emissions, and 18% of nitrous oxide
emissions. Increased agriculture,
deforestation, landfills, industrial production, and mining also contribute a
significant share of emissions. In
1997, the United States emitted about one-fifth of the total greenhouse gases.
Global mean surface temperatures have increased 0.5 – 1.0
degrees F since the late 19th century.
Sea levels has risen 4-8 inches over the past century.
Global Temperature Changes (1880-2000)
Source: U.S. Climate
Data Center, 2001
Scientists expect that the average global surface
temperature could rise 1-4.5 degrees F (0.6-2.5 degrees C) in the next fifty
years, and 2.2-10 degrees F (1.4-5.8 degrees C) in the next century, with
significant regional variation.
Sea level is likely to rise two feet along most of the U.S.
What Age Greenhouse Gases?
Some greenhouse gases occur naturally in the atmosphere,
while others result from human activities.
Greenhouse gases include water vapor, carbon dioxide,
methane, nitrous oxide, and ozone.
Carbon dioxide is released to the atmosphere when solid
waste, fossil fuels (oil, natural gas, and coal), and wood and wood products
Methane is emitted during the production and transport of
coal, natural gas, and oil. Methane
emissions also result from the decomposition of organic wastes in municipal
solid waste landfills, and the raising of livestock.
Nitrous oxide is emitted during agricultural and industrial
activities, as well as during combustion of solid waste and fossil fuels.
Changing regional climate could alter forests, crop yields,
and water supplies. It could also
threaten human health, and harm birds, fish, and many types of ecosystems. Deserts may expand into existing rangelands,
and the character of some of our National Parks may be permanently altered.
Climate Change Forcings -> Physical Processes (Biosphere,
Atmosphere, Ice, Oceans) -> Physical Responses -> Biological Processes
Scientists currently are unable to determine which parts of
the United States will become wetter or drier.
Actions are occurring at every level to reduce, to avoid and
to better understand the risks associated with climate change.
(Map of the east coast of the U.S. with markings for: Good,
Moderate, Unhealthy for Sensitive Groups, Unhealthy, and Very Unhealthy. Map is not reproducible here.)
At a national level, the U.S. Global Change Research Program
(USGRP) coordinates the world’s most extensive research effort on climate
EPA and other federal agencies are actively engaging the
private sector, states, and localities in partnerships based on a win-win
philosophy and aimed at addressing the challenge of global warming while, at
the same time, strengthening the economy.
The U.S. is working to strengthen international action and
broaden participation under the auspices of the Framework Convention on Climate
Would You Like To Wake Up Looking At This?
Or Would You Like To Inhale This?
(picture of city skyline covered in smog – not reproducible
Then You Better Make A Difference!
project for EPA was a Powerpoint Presentation concerning Global Warming. I
presented it to our Youth Advisory Board for Community Change for Youth Development.
The meeting consisted of 2 adults and approximately 10 youth. I talked about
pollution, green house affect, and how it effects the atmosphere, Thank you
for giving me the chance to build the computer. Anthony Roberts.