Measuring The Global Warming

Global warming is defined as the process of increasing the average temperature of the earth at the atmosphere, ocean, and land. Global average temperature at the earth's surface has risen by about ± 0.74-0.18 degrees Celsius over the period 1906-2005. In fact, according to the IPCC (Intergovernmental Panel on Climate Change), most of the increase in global average temperatures since the mid-2O likely caused by greenhouse gases from human activities.

Efforts to measure global warming from the beginning of 1896. At that time, scientists thought that the burning of fossil fuels will change the composition of the atmosphere and can increase the average global temperature. This hypothesis was confirmed in 1957 when researchers working in the International Geophysical Year sampled the atmosphere of the summit of Mount Mauna Loa in Hawaii.

Measurement results showed an increase in the concentration of carbon dioxide in the atmosphere. After that, the composition of the atmosphere continues to be measured carefully. The data collected shows that indeed had increased concentrations of greenhouse gases in the atmosphere.

Scientists have long suspected that the global climate warms, but they are not able to provide proper evidence. Temperature continues to vary from time to time and from one location to another location. It took years of climate observations to obtain data that shows a clear trend towards global warming. Note in the late 1980s showed little warming trend, but statistics are few and unreliable.

Weather station was originally located close to urban areas so that the temperature measurement is affected by the heat emitted by buildings and vehicles as well as heat stored by the building materials and roads. Since 1957, data obtained from weather stations that trusted the location of the station away from urban areas, as well as data from the satellite. These data provide a more accurate measurement, especially at 70% of the surface of the ocean-covered planet.

Data that more accurately shows that the trend of warming the Earth's surface is really happening. When seen at the end of the 20th century, it was noted that the ten warmest years over the last century occurred after 1980, and the three hottest years occurred after 1990, with 1998 being the hottest.

Concept diagram of climate modeling.
(Picture from: http://www.britannica.com/)

Meanwhile, climate models referenced by the IPCC shows global surface temperature of the earth will increase from 1.1 to 6.4 degrees Celsius between 1990 and 2100. Although most researchers focus on the period up to 2100, warming and sea level rise are expected to continue for more than a thousand years even if greenhouse gas levels have been stable at that time. This shows the large heat capacity of the oceans.

The IPCC panel also warned, although the concentration of gases in the atmosphere will not increase again since 2100, the climate continued to warm during certain periods due to emissions that have been released in the past. Carbon dioxide, for example, will remain in the atmosphere for more than a hundred years before the world was able to absorb it back.

If greenhouse gas emissions continue to rise, experts predict the concentration of carbon dioxide in the atmosphere can be increased up to three times in the early 22 th century when compared to the pre-industrial era. The result will be dramatic climate change.

Although the actual events of climate change has happened several times throughout Earth's history, humans will encounter this problem with a very large risk. Increasing global temperature will cause changes such as rising sea levels, increased intensity of extreme weather phenomena and changes in the amount and pattern of precipitation. Another result is the decrease of agricultural products, the loss of glaciers, and the extinction of various animal species.

Scientists have studied global warming based on computer modeling using the basic principles of fluid dynamics, radiative transfer, and other processes with some simplifications as a result of the limitations of the computer. This model predicts that the addition of greenhouse gases affect the climate warmer.

Climate models are also used to investigate the causes of recent climate change by comparing the observed changes in the models to a variety of causes, both natural and human activities. Today, the climate models can produce a well with observations of global temperature changes over the last hundred years, but did not simulate all aspects of climate. These models do not unambiguously attribute the warming that occurred between 1910 and 1945 caused by natural processes or human activity. However, these models suggest that the warming since 1975 is dominated by the emission of gases produced by humans.

Most climate models when calculating future climate is usually based Special Report on Emissions Scenarios (SRES) IPCC. That is rarely done by adding a simulation of the carbon cycle, which usually results in a positive feedback although the response is still uncertain. *** [GUN GUN GUNAWAN | PIKIRAN RAKYAT 20122012]

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