It was during the 19th century that scientists realized that gases—such as CO2—found within the atmosphere cause a "greenhouse effect" that regulates the atmosphere's temperature. Ironically, the discovery of the greenhouse effect did not happen because scientists were trying to understand global warming; it happened because they were searching for the mechanism that triggered ice ages. In an effort to understand the connection between CO2 and glacial periods, their interest was in studying the time intervals when concentrations of CO2 were at their lowest, which correlated with the glacial periods in the Earth's past climate.
The beginning of the discovery process began with Joseph Fourier in the 1820s. During this time period, scientists were beginning to understand that the gases that composed the atmosphere may trap the heat received in the atmosphere from the Sun.
Also at this time, John Tyndall, a natural philosopher, was interested in finding out whether any gases in the atmosphere could actually trap heat rays. In 1859, through a series of lab analyses, he was able to identify several gases that were able to trap and hold heat. The most important of these gases were water vapor (H2O) and CO2.
Later, in 1896, Svante Arrhenius, a Swedish chemist/physicist, who was working with data on the prehistoric ice ages, was able to determine in his laboratory that by cutting the amount of CO2 in the atmosphere by half, it could lower the temperature over Europe about 7-9°F (4-5°C)— roughly the equivalent of what would trigger another ice age.
In order for this to happen, however, the effect would have to be global. From this point, Arrhenius turned to Arvid Hogbom, who added a modern twist to the analysis. He discovered that various human activities were adding CO2 to the atmosphere at a rapid rate. At that time, he thought that the addition was not serious enough for alarm—it was not much different from other natural processes like erupting volcanoes. What he was concerned about, however, was that if the volumes continued being released into the atmosphere, it would not be long before they did start to negatively affect its quality. Arrhenius suggested that at the current rate of coal burning, the atmosphere could begin to start warming in a few centuries.
About that time, Thomas C. Chamberlin, an American geologist, became interested in atmospheric CO2 levels, and the Swedish scientist Knut Angstrom discovered that greenhouse gases do cause temperature to rise by retaining the heat instead of letting it escape to space. This added additional enlightenment to the beginning of the global warming theory.
FOURIER, ARRHENiUS, AND CALLENDAR: PIONEERS OF GLOBAL WARMING
Jean-Baptiste-Joseph Fourier, Svante Arrhenius, and G. S. Callendar are three scientists who are credited with the advancement of the science of global warming through their research and proactive leadership skills dedicated to dealing with the problem of global warming.
Jean-Baptiste-Joseph Fourier (March 21, 1768-May 16, 1830).
Jean-Baptiste-Joseph Fourier began paving the way toward the understanding of the greenhouse effect. In 1824, his work led him to believe that the gases in the atmosphere could actually increase the surface temperature of the Earth. He postulated that the properties of the Earth's atmosphere actually warm the entire planet. Once he proposed this concept, it spurred thought that the Earth actually had an "energy balance." In other words, the Earth, through various processes, was able to receive, generate, and transfer heat within its own system. When the Earth obtains energy from other sources or from within itself, it can transfer heat by conduction or convection. When the Earth obtains energy from outside sources, such as the Sun, that can cause the temperature to rise. In response, when the Earth heats up, the heat energy is changed to "infrared" radiation (longer wavelengths), and heat is reradiated outward and lost.
There is a balance between heat gain and heat loss. Fourier correctly calculated that the amount of infrared radiation increases with temperature. He also identified the fact that the Earth receives energy from the Sun, in the form of solar radiation. This works effectively because most of the atmosphere is transparent to the Sun's insolation (incoming solar radiation), allowing it to enter the atmosphere.
Svante Arrhenius (February 19, 1859-October 2, 1927).
Svante Arrhenius, from Vik, Sweden, contributed to scientific knowledge of the greenhouse effect and is credited with its discovery. Interested in developing a theory to explain ice ages, he originally speculated that it was changing levels of CO2 in the atmosphere that could significantly alter the Earth's climate via the greenhouse effect. Many of Arrhenius's ideas were based upon the work and breakthroughs of Fourier. Arrhenius theorized in 1908 that the human emission of CO2 would be strong enough to
prevent the world from entering another ice age. He was the first person to predict that emissions of CO2 from the burning of fossil fuels and other processes that use combustion machines would lead to global warming.
Still focused on ice ages, Arrhenius, however, believed that a warmer world would be better overall than a cooling one. He also made some predictions about the Earth's atmosphere based on varying the amounts of CO2. He calculated that if the current CO2 level was lowered by half, it would cause a cooling of 5.7-8.3°F (4-5°C). If, on the other hand, the CO2 was doubled, it would cause the temperature to rise 7-11°F (5-6°C). What is especially interesting about his calculations is that based on the report last issued from the Intergovernmental Panel of Climate Change (IPCC) released in 2007, they project a temperature rise of 3.3-7.5°F (2-4.5°C). The similarity between Arrhenius's and the IPCC's results are nearly the same. The only difference is that Arrhenius predicted it would take the CO2 about 3,000 years to double and cause this level of temperature rise; the IPCC has projected it will take only about 100 years.
Guy Stewart Callendar, (February 1898-October 1964).
Engineer, inventor, and amateur meteorologist.
G. S. Callendar, an amateur meteorologist, compiled a reliable global dataset of surface temperatures. He documented an upward trend in temperatures between 1900 and 1940. He was also able to correlate them in a cause-and-effect scenario to the retreat of the world's glaciers and the rising CO2 in the atmosphere as compared to the same areas before the Industrial Revolution. He also studied the infrared absorption bands and concluded that the trend toward higher temperatures was significant.
He was able to determine that it was the increase in fossil fuels that had caused the atmospheric CO2 to rise about 10 percent from the 1800s and that the increase in radiation had contributed to the rising temperatures. He was also credited with the development of the "Callendar Effect," which is defined as climate change brought about by anthropogenic increases in the concentration of atmospheric CO2.
The invaluable contribution of these scientists has allowed for the advancements seen today in the understanding of global warming and the effects it has had, is having now, and will have in the future on the environment.
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Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.