Transcript Global Warming

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 Churchill
November 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 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.
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=9tk
DK2mZlOo
Al Gore on Ocean Currents/Gulf Stream
http://www.youtube.com/watch?v=02N
RKzemXYE&feature=related
Greenland Melting
http://www.youtube.com/watch?v=1Kkr
lhoFbBM&feature=related
Consequences
MELTING 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.