The Greenhouse Effect and Global Warming
Recently, global warming has moved to a serious scientific issue. Because sunlight is constantly falling on the earth, the law of physics say that the planet has to radiate the same amount of energy back into space. Infrared radiation is sent out by the earth through the atmosphere, where molecules (carbon dioxide) hold outgoing radiation for a while, warming the surface.1 The molecules are kind of like glass in a greenhouse which is why this process of warming is called the greenhouse effect.
The greenhouse effect has been operating since the beginning of time. Without the effect, the surface of the earth would be -20 degrees Celsius, oceans would have frozen, and there would be no life on earth.The Washington Post has reported that the earth is warmer than it has been in 1,200 years.2 Recently, the summer of 1999 set records for heat in much of the United States. The average world temperature has increased one degree Fahrenheit over the last 120 years, making the world hotter than it has been in 100,000 years. From the beginning of the industrial revolution, concentrations of carbon dioxide have increased by 30%, concentrations of methane have doubled, and nitrous oxide has risen by 15%. The increases of these chemicals have enhanced the heat trapping capability of the atmosphere of the earth. Sulfate aerosols, cool the atmosphere because they reflect light back into space, but sulfates do not live long in the atmosphere.
Scientists still do not know what exactly is heating up the earth. Some say the earth is going through a natural cycle because the earth has gone through cold periods as well as hot periods. Mounting evidence is saying that humans are to blame for the rise in temperatures over the past 120 years. When we burn fossil fuel, oil, gasoline, and natural gas to run power plants, cars, and heat homes, we produce carbon dioxide. An increase in carbon dioxide magnifies the greenhouse effect. All this energy accounts for 80% of society’s carbon dioxide emissions, 25% of methane emissions, and 20% of nitrous oxide emissions. In 1994, the U.S. emitted one fifth of all the greenhouse gases in the earth. Carbon dioxide amounts are now 360 parts per million today, verses 315 per million parts in 1958, when modern technology started, and 270 per million parts in pre-industrial times. Scientists cannot actually predict what the climate will be like in the future, though. James E. Hansen, a director of NASA’s Goddard Institute for Space Studies, says that scientists know too little about the climate to make accurate predictions.”The forcings that drive long-term climate change are not known with an accuracy sufficient to define future climate change,” Hansen wrote in a journal, The Proceedings of the National Academy of Sciences.
Many people believe that carbon dioxide is nothing to worry about. And many scientists are turning away from the debate about whether human-induced global warming is taking place. It is true that Earth’s ocean, plants, soil, and animals naturally release carbon dioxide into the atmosphere. And other gases such as methane and water vapor trap solar radiation like the way a greenhouse traps the sun’s warmth. Human activities are adding more carbon dioxide to the atmosphere than are being naturally recycled. This is what scientist believe is causing global warming.
And what are the effects of global warming? Rising temperatures are expected to raise the sea level and change local climate conditions. By changing these conditions, the climate could alter forests, water supplies, and crop yields. This could also threaten human health, and harm many ecosystems of animals. Deserts could expand into range lands and many National Parks could be altered. And many of the most important impacts depend upon whether rainfall will increase or decrease. The rate of climate change is also much more important than how much the change will be because the rate will determine whether humans and ecosystems can adapt to survive. A decreased day and night temperature and night warming may happen when an increase of atmospheric greenhouse gases takes place.
Emissions are a major problem contributing to the greenhouse effect. These gases are called volatile organic compounds (VOC’s) and consist mostly of carbon, hydrogen, oxygen, and nitrogen. These gases react in sunlight with nitrogen oxides to form photochemical smog. A lab experiment was done to simulate typical outside conditions. Stems of fescue grass and white clover were cut and tested for VOC content and researchers found that emissions of certain VOC’s spiked immediately after cutting, while others continued at a high rate for the next two days. Uncut grass also gives off VOC’s and cutting grass makes it worse. In a city like Los Angeles, mowing accounts for 10% of the VOC’s in the atmosphere, say researchers.
President Bill Clinton and Vice President Al Gore have different stands on the global warming issue. Al Gore is pushing for a radical stand and wants to cut back on emissions to ten percent below the levels of 1990 and this would require a 20% cut in the fossil fuel usage. Al Gore even called for a White House conference with weather forecasters saying that the U.S. should fund more abortions in order to cut down on the number of people populating our world. Gore believes that Americans will be thankful in the long run for him saving the world from ecological disaster. Many others believe that Americans will be mad at Gore if Clinton takes Gore’s stand on the issue because energy costs will rise and the economy will slump. Not many people seem to be in favor of a rise in taxes on energy so we can cut usage and stop the warming trend. Steve Forbes is also speaking out on the global warming issue. Forbes believes that practically all of the global warming that has occurred in the past one hundred years took place before green house gas emissions took off.
During the 1990’s, many people thought that there was a connection between economic growth and carbon dioxide emissions because emissions have risen and fallen with the nation’s economic output.3 Ever since 1991, emissions have grown nearly 2% each year because the economy demanded a greater use of fossil fuels. But now research shows that there is not a link between the economy and emissions. Changes in economy such as the growth of the Internet are allowing economic growth without fuel consumption. And the Energy Information Administration says that the consumption of coal, oil, and natural gas went down last year. Now environmentalists have recommended emissions be cut to prevent the effects of a temperature rise. But many industry advocates disagree because they are afraid that doing so will lessen their economic growth.
One problem in global warming is that in August, Vice President Al Gore released photos of the Arctic ice sheet taken by satellites. These photos show that the ice is melting at a very rapid pace.4 Researchers from the University of Colorado and the British Antarctic Survey reported that 1,100 square miles of ice off Antarctica had broken off in the last year. The researchers say that the ice shelves “are in full retreat.” Last year a giant iceberg the size of Rhode Island broke off from the Ross Ice Shelf in Antarctica and poses a great danger to ships traveling through the South Atlantic Ocean. If the polar ice caps continue to melt for the next 100 years at the rate they are melting at now, all the world’s coastal cities could possibly be submerged in the sea before the end of the 21st century. And even before that happens, the temperature rise would disrupt the Earth’s climate.
Scientists have observed other warning signals about the greenhouse effect. 1998 was the warmest year recorded in history in the northeast U.S. Scientists from the University of Munich reported that spring has started to arrive earlier in Europe and autumn has arrived later. The highest temperatures ever recorded in the Pacific caused the largest die-off of corals in history. This warm weather destroyed up to 70 % of the corals.5 A Hemisphere-wide climate cycle called “Arctic oscillation” is stuck in one of its two alternating phasing, which is causing surface winds to sweep larger quantities of ocean air across the northern continents. Many scientists until now even believed in the “Medieval Warm Period” where temperatures supposedly rose through Europe and sea ice retreated in the Northern Atlantic ocean, which allowed Vikings to colonize England.6 Global warming skeptics cite the area where this happened very frequently as an example of climate variation. These skeptics say that the climate changes without the aid of people and they believe that warming would be beneficial. But now new research says that the “Medieval Warm Period” never even happened. By studying ancient tree rings, glaciers and other measurements of past climate, the thaw seems to be limited to northern latitudes in Europe and North America.
One thing being done to fight global warming is when officials from 150 nations met in Kyoto, Japan, to figure out a way to reduce greenhouse gas emissions.7 A treaty was agreed on called the Kyoto Protocol, in which the industrial nations pledged to lower their emissions by 2012. The U.S. Senate still has to ratify the treaty and other nations such as China, which produces vast amount of carbon dioxide, has refused to sign it.Other action is being taken at every level to reduce, avoid, and better understand the risks associated with climate change. Some cities and states have prepared greenhouse gas inventories and others are pursuing programs and policies that will result in the greenhouse gas emission reductions. The U.S. Global Change Research Program coordinates the world’s most extensive research effort on climate change. The Clinton Administration is aiming at addressing the challenge of global warming and at the same time strengthening the economy. Martin Parry, a geographer at University College in London proposes these measures in the reducing of global warming: Breeding food crops that can better withstand drought; discouraging people from living in flood plains; making irrigation and use of water more efficient.8 In the United States, some scientists are forming partnerships with public officials, business people, and the public to make their research known. They are going to assess what climate change means at a local and regional level.
Deforestation is another issue that is often discussed as a problem contributing to global warming that can easily be stopped.Deforestation has many negative effects such as ecological imbalance, bio-diversity loss, and climate change.Most areas in which deforestation is a problem are located in 3rd world countries. Deforestation leads to a massive extinction of species as well as vascular plant species, such as trees. When this happens, atmospheric carbon dioxide is increased because the carbon in forests is higher than in the agricultural areas which replace them.
In conclusion, global warming is an increase of the Earth’s surface temperature and the Earth’s lower atmosphere. Atmospheric greenhouse gases (water vapor, carbon dioxide, and other gases) trap outgoing energy, and retain heat like the glass panels in a greenhouse. Many people believe that humans are causing the problem with emissions from things such as cars and trucks. Others say that the warming is just part of a trend and that the world goes through warm and cold periods. If the planet continues to warm, there could be many harmful side effects.