Since the known science on climate, scientists have learned that in fact the climate on Earth is always changing. From the study of past ice ages show that the climate can change by itself, and changed radically. What causes it? Meteor falls?Variations hot sun? Volcano eruption that caused a cloud of smoke? Changes in wind direction due to changes in the structure of Earth and ocean currents? Or because of the changing composition of the air? Or other reasons?
Until recently in the 19th century, the study of the climate began to learn about the content of the gas in the atmosphere, called greenhouse gases, which could affect the climate on Earth. What is a greenhouse gas?
Actually known as 'greenhouse gases', is an effect, in which the molecules that exist in our atmosphere acts like a greenhouse effect. The greenhouse effect itself, should be a natural effect to keep the Earth's surface temperature is at normal temperature, about 30 ° C, or if not, then of course there would be no life on Earth.
In about 1820, father of Fourier discovered that the atmosphere was very able breached (permeable) by sunlight coming into the Earth's surface, but not all of the light emitted into the Earth's surface can be reflected out, infra-red radiation which should be reflected trapped, with Thus the Earth's atmosphere trap heat (the principle greenhouse).
Thirty years later, Mr. Tyndall found that the types of heat-trapping gases are mainly carbon-dioxide and water vapor, and the molecules that finally named as a greenhouse gas, as we know it today. Arrhenius later showed that if carbon-dioxide concentration doubled, the increase in surface temperature becomes very significant.
Since the discovery of Fourier, Tyndall and Arrhenius, scientists increasingly understand how greenhouse gases absorb radiation, allowing to make a better calculation for linking greenhouse gas concentrations and temperature increase. If carbon-dioxide concentrations are doubled, then the temperature may increase to 1 ° C.
However, the atmosphere was not as simple model calculations, in fact an increase in temperature can be more than 1 ° C because there are factors such as, say, changes in cloud amount, reflecting different heat between land and ocean, changes in moisture content in the air, the surface changes Earth, either because of land clearing, surface changes, or other causes, natural or due to human actions. The evidence suggests, there is an atmosphere that is getting warmer and the atmosphere holds more moisture, and store more heat, warming strengthening of the standard calculation.
Since 2001, studies on global climate dynamics indicate that at least, the world has experienced warming of more than 3 ° C since pre-industrial era, it's just if you can suppress greenhouse gas concentrations to stabilize at 430 ppm CO2e (ppm = parts per million = per million of CO2 equivalent - which states the ratio of the number of CO2 molecules per million air dry). To be sure, since 1900, the Earth has experienced warming of 0.7 ° C.
Then, if warming does occur, as it is called; which became known as global warming, (or in popular terms the English language, we refer to as Global Warming): Is it an unavoidable natural phenomenon? Or is there some reason that exhibited significantly, so it became 'popular' as it is today? Is it because Al Gore with his film "An Inconvenient Truth" to popularizing global warming? Surely not that simple.
Need international cooperation to be able to say that the man was who was the main cause of global warming. Report of the IPCC (Intergovernmental Panel on Climate Change) in 2007, showed that the average global human activity causing the warming since 1750. Changes in the abundance of greenhouse gases and aerosols due to solar radiation and the entire surface of the Earth's climate system affects energy balance. In a quantity that is expressed as radiative Forcing as measure whether the global climate be hot or cold (positive values in red states or cause to be warmer, and blue the opposite), it was found that was the result of human activity (anthropogenic), which became the main driver of global warming
From the figure shows that the carbon-dioxide is a major contributor to gas emissions. From pre-industrial period of 280 ppm to 379 ppm in 2005. This figure exceeds the natural rate of studies of past climate changes (paleoclimatology), where over 650 thousand years is only an increase of 180-300 ppm. Especially in the last decade (1995-2005), recorded an increase of the largest concentrations of carbon-dioxide per year (1.9 ppm per year), much greater than atmospheric measurements in 1960, (1.4 ppm per year), although there are variations in peryears.
Sources, especially the increase of carbon-dioxide concentration is the use of fossil fuels, plus the influence of changes in land surface (land clearing, logging, forest fires, melting ice). Increased concentrations of methane (CH4), of 715 ppb (part per billion = one per billion) in pre-industrial to 1732 ppb in the early 1990s, and 1774 in 2005. This exceeds the number that changed naturally over 650 thousand years (320-790 ppb). The main source of methane increased agriculture and fossil fuel use. The concentration of nitrous oxide (N2O) from 270 ppb - 319 ppb in 2005. As well as the other contributor to emissions, is the main source of human agriculture.The combination of the three main components of the became the biggest contributor to global warming.
Anthropogenic contributions to aerosols (sulfate, organic carbon, black carbon, nitrate and dust) gives a cooling effect, but the effect is still not dominant than warming, in addition to the uncertainty calculations are still very large. Likewise, changes troposper ozone formation due to chemical processes of ozone (nitrogen oxides, carbon monoxide and hydrocarbons) contribute to global warming. The ability of sunlight reflectance (albedo), due to changes in the Earth's surface and the deposition of black carbon aerosols from the snow, resulting in changes that vary, from cooling to heating. Changes from the sun rays (solar irradiance) does not contribute to global warming.
Thus, it is understandable that there is indeed a role for the human self, because of global warming caused by human actions alone. Then how the impact of Global Warming for life? Flow time prediction and impact of science perspective can be read on the second part of this paper.
The warmth of the earth is very useful for kalangsungan human life, but warm here does not mean uncomfortable, can be said to be very dangerous. Earth's risingtemperatures cause the disruption of ecosystems keseimbanganan a result of globalwarming. Global warming is a condition in which the Earth's temperature rises as a result of greenhouse effect gases.
The greenhouse effect is caused by rising concentrations of carbon dioxide gas (CO2) and other gases in the atmosphere. The increase in CO2 concentration is due to the increase in fuel oil combustion, coal and other organic fuels which exceed the ability of plants and the ocean to absorb it.
Energy entering the Earth: 25% reflected by clouds or other particles in the atmosphere, clouds absorb 25%, 45% absorbed by the earth's surface, dan5% is reflected back by the earth's surface. The absorbed energy is reflected back in the form of infrared radiation by clouds and the earth's surface. But most of the infrared emitted by clouds and the earth retained CO2 and other gases, to be returned to the earth's surface. Under normal circumstances, the greenhouse effect is necessary, with the greenhouse effect the temperature difference between day and night on earth is not too much different.
IPCC (The Intergovernmental Panel on Climate Change) was established by the World Meteorological Organisation (WMO) and the United Nations Environment Programme (UNEP) is an agency panel composed of scientists from around the world whose primary job is to analyze the scientific evidence on global warming and climate change. The IPCC was established to address the very thorny issue of climate change. The decision makers need a source of objective and accurate information about the causes of climate change, its impact on the environment, social economy and alternative ways to overcome and adapt to climate change.
According to them, among other positive impacts:
Higher potential agricultural output is in an area that lies in the middle latitude.
Potential increase in global timber forests are well managed and properly.
Increased water availability for populations in some areas are relatively dry, for example in parts of Southeast Asia.
Reduction of mortality in the winter on earth in this part of the middle latitudes and high latitudes.
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