Most scientists around the world agree that the earth’s temperature is rising. In the past 100 years, the average surface temperature of earth has risen 0.45-0.6 degrees Celsius (°C) (0.8-1.0 degrees Fahrenheit - °F). This rising of the earth’s temperature is commonly referred to as global warming. This slight rise in temperature might not sound like much to be concerned about. However, the rise in temperature that caused the end of the last ice age, was only 5°C (9°F). We can therefore see that such small temperature changes can have drastic impacts on the earth. It should also be noted that that rise in temperature over millions of years, a rate much slower than the current rise. Scientists now are predicting that global temperatures will rise another 0.9-3.5°C (1.6-6.3°F) in the next hundred years, at which rate it would only be 200 years before global temperatures have risen another 5°C.
Global warming has many potentially adverse effects. Many of earth’s organisms can only survive within a very small range of temperatures. The biological processes that take place within these organisms, such as metabolism and respiration, are highly temperature dependent. One of the most serious implications of global warming is the rate at which it is occurring. Some organisms are able to adapt to environmental changes, such as a rise in temperature. However, some scientists say that global warming is now occurring much to fast to allow time for such adaptations to occur. Some organisms would most likely become extinct because they could not adapt to the rapidly changing temperature.
Not all organisms are so temperature dependent, a few can adapt rapidly enough to survive, and yet others can migrate to more appropriate climates when their environment changes. Keep in mind that migration is dependent on their being a way for the organisms to migrate. Not all organisms have the ability to fly or swim, and as temperatures rise, some landmasses will be cut off by rising sea levels.
Rising temperatures also have an obvious effect on the earth’s weather patterns. These changes do not occur uniformly across regions and therefore may cause complete alteration of various ecosystems. For example, precipitation has increased one percent in the past century, mainly in high latitudes. However, precipitation has actually decreased in tropical regions. With arid regions becoming more humid and vice versa, some ecosystems will deteriorate and become less abundant, while others will thrive. Many species are dependent on specific types of habitat. If some of these habitats become extinct, so will the organisms that depend on them. Therefore, this combined with the direct species effects mentioned above, could have a serious impact on global biodiversity.
Rising temperatures are also causing a rise in sea level – through both increased precipitation and glacial melting. Worldwide, sea level has risen approximately 15-20cm (6-8 inches) in the last century. Of this, about 2-5 cm (1-2 inches) can be attributed to glacial melting. Another 5-7 cm is attributed to the expansion of the oceans as the water warmed. Another contributing factor to rising sea level is the rising and sinking of various landmasses, due to depleted groundwater aquifers and other factors. If sea level continues to rise at this rate, entire island nations may soon be under water.
A lot of research has been done on the cause(s) of global warming. In 1998, the World Meteorological Organization (WMO) and the United Nations Environmental Programme (UNEP) established the Intergovernmental Panel on Climate Change (IPCC). The purpose of this organization is to assess the scientific, technical and socio-economic information necessary to understand the risk of human-induced climate change. This organization consists of more than 2000 of the world’s leading climate scientists, and they have concluded that global climate is highly affected by human activities.
According to the IPCC, the primary influence
on climate is the greenhouse gases: carbon dioxide (CO2), ethane, and nitrous
oxide. The earth’s atmosphere naturally traps heat from the
sun through a process known as the “greenhouse effect”. It is because
of the greenhouse effect that the maintains a comfortable average temperature
of 60°F. The greenhouse gases are responsible for this regulation of
the earth’s temperature. However, concentrations of the greenhouse gases
in the atmosphere are rising, thus increasing the temperature of the earth.
This increase in concentrations of greenhouse gases is partially due to changes in agricultural and industrial practices during the industrial revolution. During this time the fossil fuels, including coal, oil and natural gas, became common energy sources. One major by-product of the burning of fossil fuels is Carbon dioxide, a greenhouse gas. Therefore with the increased use of the fossil fuels, atmospheric concentrations of carbon dioxide began to rise. Since that time, CO2 concentrations have increased 30%, methane concentrations have more than doubled, and nitrous oxide concentrations have risen by 15%. Fossil fuels are now commonly used to power cars and trucks, heat homes, and generate electricity. If we continue to use today’s technology and if global population and economy continue to grow emissions of CO2 and the other greenhouse gases will continue. If the amount of greenhouse gas emissions continues at its present rate, then atmospheric concentrations will continue to grow, thus further enhancing the greenhouse effect and cause global warming.
Another human activity that enhances global warming is deforestation. Earth has a natural capacity for assimilating carbon dioxide through the process of photosynthesis, which takes place in primary producers such as trees and phytoplankton. Photosynthesis is an important part of the carbon cycle because it maintains healthy levels of CO2 in the atmosphere. However, deforestation reduces the amount of trees available to carry out photosynthesis, and thus reduces the capacity of the earth to assimilate CO2. Because CO2 is now being released into the atmosphere faster than it can be assimilated through photosynthesis, concentrations of CO2 in the atmosphere are increasing.
Many people refer to global warming as a crisis. It is a common misconception that there is nothing an individual can do to abate global warming. One of the best ways to prevent further increase of greenhouse gases is to reduce their emissions. Changing individual consumption patterns may be one of the most effective ways of doing this. Most energy in the United States is produced by the burning of fossil fuels. By reducing our individual use of energy derived from fossil fuels, we can contribute to reduced emissions.
Saving energy is as simple as turning off lights when you leave the room. Turn off stereos, computer monitors and other electronic equipment when they are not in use. We can also save energy by buying energy efficient home appliances and fuel-efficient cars, and making sure these things are well maintained. Additionally, using public transportation, car pooling, biking, walking or rollerblading to work is much more fuel efficient than driving a car at all.
Besides being highly pollutant, fossil fuels are also a limited resource. There is not an infinite supply of fossil fuels, and some day we will run out. Because of this, it is important to develop new technologies for producing energy. Many of these technologies have already been developed, and are much cleaner than fossil fuels. Solar, wind, geothermal, and hydro-powered technologies are becoming more and more popular as alternatives to fossil fuels.
International governments are also taking actions to promote the abatement of global warming. In 1997, the Parties to the United Nations Framework Convention on Climate Change (including the U.S.) met in Kyoto, Japan to sign the Kyoto Treaty. This treaty set emissions targets for each country who signed to reduce emissions over a five year period, and outline a program for international emissions trading and technological help for developing countries. Unfortunately, before action on the Treaty is taken in the U.S. it must be approved by the U.S. Senate. At this time, it has not yet been submitted to the Senate, but the U.S. does continue to participate in international negotiations related reducing emissions.
Another method for reducing greenhouse
gases is to increase their uptake by the environment. This can be done
by stimulating the increase of photosynthetic production by primary producers.
For this reason there has been a large movement to promote planting trees
and restoring forests. However, because trees grow so slowly, this is not
a highly effective method of abatement. Therefore scientists are also investigating
ways to stimulate phytoplankton growth in the oceans.