Your Name Your Title Your Organization (Line #1) Your Organization (Line #2) Global warming.: Matthieu BERCHER, Master M.I.G.S., University of Burgundy, 27/10/ :45 :. Introduction Observations and graphs Causes of the climate change Consequences of the climate change The climate future of the Planet

(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 mid- twentieth 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 ºC (that's º F) by the end of the 21st century. The difference between global temperatures during an Ice Age and an ice- free 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 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

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