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Introduction
Observations and graphs
Global warming
Causes of the climate change
Consequences of the climate change
The climate future of the Planet
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.: Matthieu BERCHER, Master M.I.G.S., University of Burgundy, 27/10/2008
08:45 :.
(1) Introduction
Global warming is the increase in the average temperature of the Earth's
surface and oceans since the 20th century, and its projected continuation.
During millions of years, the climate of the Earth had a lot of modifications.
The various causes of these changes are volcanoes, sun.
But for some decades, the influence of the man
increases and modifies the climate.
On February 2007, the United Nations scientific panel
declared that the evidence of a warming trend is
"unequivocal," and that human activity has "very
likely" been the driving force in that change over the
last 50 years.
Nowadays, Global warming is accepted by scientists
as a fact.
(1) Introduction
Two millennia of mean surface temperatures according to different
reconstructions.
(2) Observations and graphs
Global surface temperature increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during
the 100 years ending in 2005.
(3) Causes of the climate change
This warming is largely attributed to the increase of greenhouse gases
(carbon dioxide and methane) in the Earth's atmosphere caused by
human burning of fossil fuels, industrial, farming, and deforestation
activities.
The Intergovernmental Panel on Climate Change (IPCC) concludes "most of
the observed increase in globally averaged temperatures since the midtwentieth century is very likely due to the observed increase in
anthropogenic greenhouse gas concentrations" via an enhanced
greenhouse effect.
Natural phenomena such as solar variation combined with volcanoes
probably had a small warming effect from industrial times to 1950 and a
small cooling effect from 1950 onward.
(3) Causes of the climate change : Solar variation over the last thirty years
Solar cycles led to a small increase of 0.07 percent in brightness. This
effect is too small to contribute significantly to global warming.
(3) Causes of the climate change : Carbon dioxide concentration over
the last 10,000 years.
The carbon dioxide concentration increased a lot in the two last centuries.
(3) Causes of the climate change : Methane concentration over the last
10,000 years.
(3) Causes of the climate change : Measures of Carbon Dioxide
concentration in Hawaii
Components of the current radiative forcing as estimated by the IPCC
The forces that drive climate change are said to be operating in a system
called forcing.
Global and continental temperature change
This observations confirms that the increasing of temperature is due to the
human activities.
Greenhouse gas emissions by country in 2000
Poor regions, particularly Africa, appear in countries which their emissions
have been small compared to the developed world.
Per capita greenhouse gas emissions by country in 2000
(4) Consequences of the climate change
Increasing global temperature is expected to cause sea levels to rise, an
increase in the intensity of extreme weather events, and significant
changes to the amount and pattern of precipitation, likely leading to an
expanse of tropical areas and increased pace of desertification. Other
expected effects of global warming include changes in agricultural yields,
modifications of trade routes, glacier retreat, mass species extinctions and
increases in the ranges of disease vectors.
Average glacier thickness change
Northern Hemisphere ice trends
Southern Hemisphere ice trends.
The ozone layer
The hole in the ozone layer is provoked by the gases rejected by human
activity. This hole amplify the global warming.
(5) The climate future of the Planet
Average global temperatures may increase by 1.4-5.8ºC (that's 2.5 - 10.4º F)
by the end of the 21st century.
The difference between global temperatures during an Ice Age and an icefree period is only about 5ºC.
Warmer ocean water may result in more intense and frequent tropical
storms and hurricanes. Sea levels are also expected to increase by 0.09 0.88 m. In the next century, mainly from melting glaciers and expanding
seawater . Global warming may also affect wildlife and species that cannot
survive in warmer environments may become extinct. The global warming
may result in the spreading of certain diseases such as malaria and
diseases due to the poor air quality.
The future problems caused by rising seas, growing deserts, and more
frequent droughts which can affect the developing world more than rich
countries.
One study predicts 18% to 35% of a sample of 1,103 animal and plant
species would be extinct by 2050, based on future climate projections.
(5) The climate future of the Planet : global warming predictions
The globally averaged warming corresponds to 3.0 °C (5.4 °F).
Data Internet
http://en.wikipedia.org/wiki/Main_Page
http://www.nytimes.com
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