Global Warming

Global warming is the process of increasing the average temperature of the atmosphere, ocean, and land surface. Global average temperature at the earth's surface has increased by 0.74 ° C ± 0:18 (1:33 ± 0:32 ° F) during the last hundred years. Intergovernmental Panel on Climate Change (IPCC) conclude that, "most of the increase in global average temperature since the mid -20th century, most likely caused by increased concentrations of greenhouse gases resulting from human activity through the greenhouse effect. Basic conclusions have been presented by at least 30 scientific societies and academies, including all the national science academies of the G8 nations. However, there are still some scientists who do not agree with some of the conclusions that the IPCC stated. Climate models referenced by the IPCC project shows global surface temperature will increase by 1.1 to 6.4⁰ C (2.0 to 11.5⁰F) between 1990 and 2100. Different guesstimate was caused by the use of different scenarios on emissions of greenhouse gases in the future, as well as models with differing climate sensitivity. While most research focuses on the period up to 2100, warming and sea level rise is expected to continue for more than a thousand years even if greenhouse gas emissions has stabilize reflects the large heat capacity of the oceans. "

 

Increasing global temperature will cause other changes such as rising sea levels, increased intensity of extreme weather phenomena and changes in the amount and pattern of precipitation. The effects of global warming include its impact on agricultural output, loss of glaciers, and the extinction of various animal species. Cause of Global Warming are:

1 . Greenhouse Effect

All energy sources that exist on Earth comes from the Sun. Most of the energy in the form of short- wave radiation, including visible light. When this energy arrives Earth's surface, he turned from the light into heat that warms the Earth. The surface of the Earth, will absorb some of the heat and reflect the rest. Some of this heat tangible long-wave infrared radiation into space. However, some of the heat remains trapped in the Earth's atmosphere due to accumulated amount of greenhouse gases include water vapor, carbon dioxide, sulfur dioxide and methane into the trap this radiation. These gases absorb and reflect radiation emitted heat the Earth, and consequently will be stored on the surface of the Earth. This situation occurs continuously, resulting in an annual average temperature of the earth continues to rise.

2 . Feedback Effects

Nasir cause of global warming is also influenced by a variety of feedback processes that result. An example is the evaporation of water. In the case of warming due to increasing greenhouse gases such as CO₂, warming will initially lead to more water to evaporate into the atmosphere. Because water vapor is itself a greenhouse gas, warming will continue and increase the amount of water vapor in the air until it reaches equilibrium with the water vapor concentration. The resulting greenhouse effect greater than the effect of CO₂ alone. (Although this feedback increases the absolute water content in the air, the relative humidity of the air is almost constant or even decreases slightly because the air becomes warmer). This feedback affects only slowly as CO₂ has a long time in the atmosphere. Another important feedback is the loss of reflectance (albedo) of ice. As global temperatures increase, ice near the poles melts at an increasing rate. Along with melting ice, land or water below will open. Both land and water has the ability to reflect light much less when compared to ice, and consequently will absorb more solar radiation. This will add to the heating and causing more ice to melt, causing a continuous cycle.

3. Variations in the Sun

There is a hypothesis that states that the variation of the Sun, with a possibility reinforced by feedback from clouds, can contribute in the current warming. The difference between this mechanism with the warming due to the greenhouse effect is the increased activity of the Sun would heat the stratosphere reverse the greenhouse effect should cool the stratosphere . Cooling of the lower stratosphere has been observed at least since 1960 , that will not happen when solar activity being the main contributor to recent warming. (Depletion of the ozone layer can also provide the cooling effect but the depletion occurred from late 1970's). Phenomenon solar variability combined with volcanic activity may have given the warming effect from pre - industrial to 1950, as well as a cooling effect since 1950.

There is some research that states that the contribution of the Sun may have been overlooked in global warming. Two scientists from Duke University estimated that the Sun may have contributed to the 45-50 % increase in global average temperature over the period 1900-2000, and about 25-35 % between 1980 and 2000. Stott and his colleagues argued that the climate models are used as guidelines now make exaggerated estimates of the effect of greenhouse gases compared to the influence of the Sun, they also argued that the cooling effects of volcanic dust and sulfate aerosols have also been underestimated. Nevertheless, they conclude that even by increasing the sensitivity of climate to solar influences though, most of the warming that has occurred in recent decades is due to greenhouse gases.

In 2006, a team of scientists from the United States, Germany and Switzerland declared that they did not find an increase in the level of " testimony " from the Sun in the last thousand years. Solar cycle is only a small increase of 0.07 % in the rate of " statement " during the last 30 years. This effect is too small to contribute to global warming. A study by Lockwood and Fröhlich found no relation between global warming and solar variability since 1985, whether through variations of solar output or variations in cosmic rays.

4.      Carbon dioxide pollution from fossil-fuel power plants

Our increasing dependence on electricity from fossil fuel power plants to make the increasing release of carbon dioxide from the combustion gases to the atmosphere. Approximately 40% of global carbon dioxide pollution, originating from the U.S. electricity production. This need will continue to increase every day. Apparently, the business use of alternatives to fossil energy should be immediately implemented. However, there are still many of us are reluctant to do this. 

5.      Carbon dioxide pollution from burning gasoline for transportation

Other sources of carbon dioxide pollution comes from motor vehicle engines. Moreover, the situation is getting worse by the fact that demand for motor vehicles each year continues to increase along with the human population is growing very rapidly. Unfortunately, all this increasing is not matched by efforts to reduce the impact. 

4.      Methane gas from livestock and agriculture.

Methane is second only to carbon dioxide that causes the greenhouse effect. Methane gas can made from of organic matter is broken down by bacteria under conditions of oxygen deprivation, for example in a farm. This process can also occur in the intestines of farm animals, and with the growing number of livestock, resulting in increased production of methane gas that is released into the Earth's atmosphere.

5.      Activity logging

Frequent use of wood from trees as raw materials to make our diminishing number of trees. Moreover, the forest as a place of trees we grow increasingly narrow due converted to plantations such as oil palm. In fact, very important forest functions as the lungs of the world and can be used to recycle carbon dioxide released in the atmosphere.

6.  Excessive use of chemical fertilizers 

          In the span of the last half of the 20th century, the use of chemical fertilizer for farming increased rapidly world. Most of these chemical fertilizers are made ​​nitrogenoksida 300 times more potent than carbon dioxide as a heat trap, so it would heat up the earth. Another result is that chemical fertilizers seep into the ground can contaminate the sources of our drinking water. 

 

The scientists used computer models of temperature, precipitation patterns, and atmospheric circulation to study global warming. Based on these models, scientists have made some estimates of the impact of global warming on weather, sea levels, coastal, agricultural, wildlife and human health.

1. Unstable climate began 

   Scientists predict that during global warming, the northern regions of the Northern Hemisphere (Northern Hemisphere) will heat up more than other areas on Earth. As a result, mountains of ice will melt and the land will shrink. Will be less ice floating on the northern oceans. Areas that previously experienced mild snow, probably will not get it again. In mountainous areas in temperate, snow-covered part will shrink and will melt faster. Growing seasons will be longer in some areas. Temperatures in winter and at night will tend to increase.     

    Warm regions will become more humid as more water evaporates from the oceans. Scientists are not yet sure whether the moisture will actually increase or decrease the warming even further. This is because water vapor is a greenhouse gas, so its presence will increase the insulation effect of the atmosphere. However, more water vapor will also form more clouds, so it would reflect sunlight back into space, where it will reduce the heating process. High humidity will increase rainfall, on average, about 1 percent for each degree Fahrenheit warming. Storms will become more frequent. In addition, the water will evaporate more quickly than soil. As a result, some areas will become drier than ever. The wind will blow harder and probably with different patterns. Typhoon ( hurricane ) which draws its strength from the evaporation of water, will be greater. Contrary to the warming that has occurred, some very cold periods may occur. Weather patterns become less predictable and more extreme.

2. Rise Sea Level

 Changes in the average height of the sea surface area measured with stable environments geology. When the atmosphere warms, the surface layer of the oceans will warm, so the volume will expand and raise sea levels. Warming will also melt a lot of ice at the poles, especially around Greenland, which will raise the volume of water in the ocean. Sea levels worldwide have risen 10-25 cm (4-10 inches) during the 20th century, and IPCC scientists predict a further rise of 9-88 cm (4-35 inches) in the 21st century. Changes in sea levels will greatly affect life in the area. The increase in 100 cm (40 inches) would submerge 6 percent of the Dutch area, 17.5 percent of the Bangladesh, and many of the islands. Erosion of cliffs, beaches and sand dunes will increase. When the high seas to reach the mouth of the river, tidal flooding will increase in the mainland. Rich countries will spend huge amounts of money to protect the coastal area, while poor countries may only be able to evacuate from coastal areas.

Even a small rise in sea level will affect coastal ecosystems. Increase of 50 cm (20 inches) would submerge half of the coastal wetlands in the United States. New marshes will also be formed, but not in urban areas and areas that are already built. The sea level rise will cover most of the Florida Everglades. 

3.      Global temperatures tend to increase

         One might assume that a warmer Earth will produce more food than ever, but it is actually not the same in some places. Southern parts of Canada, for example, may benefit from the higher rainfall and growing season length. On the other hand, semi- arid tropical agriculture in some parts of Africa may not be able to grow. Agricultural areas that use irrigation water from distant mountains may suffer if the snowpack ( snow collection ) winter, which serves as a natural reservoir, would melt before the peak months of the growing season. Crop and forest insect attack and may experience a more severe disease.

4.  Ecological disturbance

    Animals and plants are living things that are difficult to avoid the effects of global warming because most of the land is controlled by humans. In global warming, animals tend to migrate toward the poles and up mountains. Plants will change the direction of growth, looking for new areas as old habitats become too warm. However, human development will deter this movement. Species that migrate north or south that are blocked by the cities or agricultural lands may be dead. Some types of species that are not able to quickly move toward the poles may also be destroyed.