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Global Warming

Introduction

In 1827, French mathematician and physicist Jean Fourier began the formal discussion which has led to the debate of global warming by identifying the thin atmospheric blanket which serves to warm the earth. Fourier suggested that the earth's atmosphere contains certain properties which resemble those of a greenhouse that allow solar energy to enter the atmosphere and appear on earth as visible light. These properties then, however, obstruct the return a portion of the energy into space by absorbing and re-radiating it as infrared heat to the earth. These "properties" that Fourier identified have turned out to be the greenhouse gases in the atmosphere which allow this process to occur. What Fourier discovered has come to be called the greenhouse effect. In recent years, human activity, centered around industrialization, has contributed excessive amounts of the greenhouse gases to the atmosphere, leading to a controversial phenomenon called global warming.

Geologic Processes and Products

The idea of global warming centers around a process called the greenhouse effect. This term is often interpreted as having negative results because of its connection to the damaging effects of global warming. The greenhouse effect, however, is a vital component of life on earth. This process keeps the earth's temperature about 59 degrees (F) warmer than it would be otherwise, providing a livable atmosphere for human life. This process becomes detrimental to the environment and its ecosystems when the greenhouse effect, which is normal and essential, is amplified by human activity, sending excess amounts of greenhouse gases into the atmosphere. Human actions such as the waste produced by factories increase the atmospheric concentrations of naturally occurring greenhouse gases such as water vapor, carbon dioxide, methane, nitrous oxide, and tropospheric ozone. In addition to the production of these extra natural gases, synthetic greenhouse gases are also being added to the atmosphere, including chloroflorocarbons and halons.

Impacts

Wildfires have become more common in recent years and are expected to be seen even more in the future, due largely to higher temperatures and decreased soil moisture which leads to drought. Wildfires, as well as pest infestations and disease in crops and trees, are more likely in times of sustained drought.

Global warming is an issue worldwide, but it has very different impacts in different regions. On each continent, the effects of global warming have varied.

~Africa has the lowest per capita fossil fuel use of any major region, but because of limited capabilities to adapt to climate change due to high rates of poverty, Africa could be the most vulnerable continent to the effects of global warming. Between 1985 and 1995, Southern Africa experienced both the warmest and driest decade on record. 92 percent of the Lewis glacier, Mt. Kenya's largest, has melted over the past 100 years. Many areas have also seen coral reef bleaching and increased malaria rates.

~Antarctica has seen very recent and dramatic evidence of global warming. In only 35 days, from February to March 2002, a piece of the Larsen B ice shelf which measured 1260 square miles, an area larger than that of Rhode Island and having the thickness of a 60 story building, simply disintegrated. Scientists say that there has been a continual warming trend in the region of 4.5 degrees Farenheit since the 1940's.

~Asia has been affected in many different ways by global warming and scientists predict that there will be much more serious implications in the future. For example, scientists expect the loss of all central and eastern Himalayan glaciers by the year 2035 if the rate of retreat they current see continues. Malaria has spread to record high elevations. Also, coral reef bleaching can be seen in many areas, as well as highly detrimental flooding and wildfire.

~Australia, considered to be one the the most diverse ecosystems on earth, has seen many damaging changes due to global warming. Sea temperatures have increased in recent years, damaging the magnificent coral reefs and many places have experienced land loss in the form of shore recession. Also, incidents of extremely heavy rainfall for the region have poured down as much as 12 inches of rain at a time.

~Europe has experienced many changes in its environment this century, varying greatly among regions within its own borders. In most places, the temperature increased even more than the global average. For the most part, precipitation levels increased in the north and decreased in the south. Some processes, such as plant and animal activities have shifted timing and location to adjust to changing environments. The Alps have provided evidence of global warming in the form of widespread retreat of glaciers. In Spain, half of the glaciers that were present in 1980 have now disappeared. Experts are trying to urge the industrialized countries of Europe to take action to reduce gas emissions that contribute to the amplified greenhouse effect induced by human activity.

~North America is home to 9 of the 10 "hotspot" categories, producing such dramatic changes as polar warming in Alaska, coral reef bleaching in Florida, and marsh loss in Chesapeake Bay. Within the continent's diverse array of ecosystems, there has recently been seen beach and glacial retreat, marsh and island loss, record level heat and both the driest and wettest seasons ever seen in the region. One may think that these kinds of evidence of the damaging effects of global warming would inspire industrialized countries to reconsider their methods. However, the United States and Canada continue to be two of the largest emitters of greenhouse gases that contribute to this problem worldwide.

~South America is a place where people depend greatly on the natural resources of the region for survival. These natural resources have been threatened in recent years in many ways due to the effects of global warming. The higher global temperatures have contributed to increased drought, melting glaciers which threaten water supplies in the future, glacial retreat, disease being found at higher elevations, sea level rising, and coral reef bleaching.

So, it appears that, while different regions of the world experience it differently, global warming is a problem worldwide. Also, it seems that the regions which produce the greatest amounts of damaging greenhouse gases are not necessarily the ones which see the most severe negative impacts.

Literature Cited

Global Investigator

Earth: An Introduction to Physical Geology. Tarbuck, Edward J. and Lutgens, Frederick K. Prentice-Hall Inc. Upper Saddle River, New Jersey. 2002. P. 591-593.

"Marine biodiversity hotspots and conservation priorities for tropical reefs" Science.295, no. 5558; American Assoc. for the Advancement of Science, United States.

National Climatic Data Center

National Environmental Satellite, Data, and Information Service

National Oceanic and Atmospheric Administration

National Snow and Ice Data Center (March 18,2000)

"Our Shifting Climate." Salinger, J. and B. Mullan; New Zealand Science Monthly, vol. 9, no. 9; South Pacific Publications, New Zealand.

World Meterological Organization

"Warming of the Southern Ocean Since the 1950s." Gille, Sarah T.; Science, vol. 295, no. 5558; American Association for the Advancement of Science, United States.

World Resources Institute

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Copyright ©-2001 Earlham College. Revised 25 February 2002. Send corrections or comments to csizmti@earlham.edu