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The Greenhouse Effect The Earth’s greenhouse effect is a natural occurrence that helps regulate the temperature of our planet. When the Sun heats the Earth, some of this heat escapes back to space. The rest of the heat, also known as infrared radiation, is trapped in the atmosphere by clouds and greenhouse gases, such as water vapor and carbon dioxide. If all of these greenhouse gases were to suddenly disappear, our planet would be 60°F colder and would not support life as we know it. However, human activities, such as the burning of fossil fuels and deforestation, have enhanced the natural greenhouse effect by adding greenhouse gases to the atmosphere causing the Earth’s average temperature to rise.
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Global Warming
“The Era of Procrastination, of Half-Measures, of Soothing and Baffling
Expedients, of Delays, is Coming to its Close.
In its Place We are Entering a Period of Consequences.”
-Sir Winston ChurchillNovember 12, 1936
Climate Change or Global Warming?
According to the National Academy of Sciences, "the phrase 'climate change' is
growing in preferred use to 'global warming' because it helps convey that there are [other] changes in addition to
rising temperatures." Climate change
refers to any significant change in measures of climate
(such as temperature, precipitation, or wind)
lasting for an extended period
(decades or longer).
Global warming is an average increase in the
temperature of the atmosphere near the Earth's surface and in
the troposphere, which can contribute to changes in global climate patterns.
The Greenhouse EffectThe Earth’s greenhouse effect is a natural
occurrence that helps regulate the temperature of our planet. When the Sun heats
the Earth, some of this heat escapes back to space. The rest of the heat, also known as
infrared radiation, is trapped in the atmosphere by clouds and greenhouse gases, such as water vapor and carbon dioxide. If all of these greenhouse gases were to suddenly
disappear, our planet would be 60°F colder and would not support life as we know it.
However, human activities, such as the burning of fossil fuels and deforestation, have enhanced
the natural greenhouse effect by adding greenhouse gases to the atmosphere causing
the Earth’s average temperature to rise.
Carbon Dioxide Levels Rising
Carbon dioxide and other air pollution that is collecting in the atmosphere like a thickening blanket, trapping the
sun's heat and causing the planet to warm up. Coal-burning power plants are the largest U.S. source of
carbon dioxide pollution -- they produce 2.5 billion tons every year. Automobiles, the second largest source,
create nearly 1.5 billion tons of CO2 annually. Over the past 50 years the average global
temperature has increased at the fastest rate in recorded history. And experts think the trend is
accelerating: The World Meteorological Organization reported that 2000-2009 was the hottest decade on record, with 8 of the hottest 10 years having occurred since 2000. Scientists
say that unless we curb global warming emissions, average U.S. temperatures could be
3 to 9 degrees higher by the end of the century.
Al Gore on Carbon Dioxide Levels http://www.youtube.com/watch?
v=9tkDK2mZlOoAl Gore on Ocean Currents/Gulf
Streamhttp://www.youtube.com/watch?v=02NRKzemXYE&feature=related
Greenland Meltinghttp://www.youtube.com/watch?v=1KkrlhoFbBM&feature=related
ConsequencesMELTING GLACIERS, EARLY SNOWMELT AND SEVERE
DROUGHTS WILL CAUSE MORE DRAMATIC WATER SHORTAGES IN THE AMERICAN WEST.
RISING SEA LEVELS WILL LEAD TO COASTAL FLOODING ON THE EASTERN SEABOARD, IN FLORIDA, AND IN
OTHER AREAS, SUCH AS THE GULF OF MEXICO.
WARMER SEA SURFACE TEMPERATURES WILL FUEL MORE INTENSE HURRICANES IN THE SOUTHEASTERN
ATLANTIC AND GULF COASTS.
FORESTS, FARMS AND CITIES WILL FACE TROUBLESOME NEW PESTS AND MORE MOSQUITO-BORNE DISEASES.
DISRUPTION OF HABITATS SUCH AS CORAL REEFS AND ALPINE MEADOWS COULD DRIVE MANY PLANT AND
ANIMAL SPECIES TO EXTINCTION.
Evidence
Abrupt Climate Change
Abrupt climate change refers to sudden (on the order of decades), large changes in some major component of the climate system, with rapid, widespread effects. The potential for abrupt climate changes
cannot be predicted with confidence; however, abrupt climate changes are an important consideration because, if triggered, they
could occur so quickly and unexpectedly that human or natural systems would have difficulty adapting to them (NRC, 2002).
Abrupt climate changes occur when a threshold in the climate system is crossed – a trigger that causes the climate to rapidly shift from one
state to a new, different one (Schneider et al., 2007).
These triggers can be forces that are “external” or “internal” to the climate system. Examples of these triggers include:
changes in the Earth’s orbit a brightening or dimming of the sun melting or surging ice sheets
strengthening or weakening of ocean currents emissions of climate-altering gases and particles into the atmosphere
More than one of these triggers can operate simultaneously, since all components of the climate system are linked.
