GLOBAL AND REGIONAL PERSPECTIVES ON GLOBAL WARMING ISSUE
Abstract: Climate change and global warming have been the issues that have grabbed the attention of the entire world during this decade. The debate is on between the developing countries and the developed countries about climate change and its impact on the environment. The developing countries do not want to follow certain guidelines which are to be implemented because they do not want to affect their national growth and productivity. On the contrary, they emphasize that actions are required to be taken by the developing nations that are responsible for the current crises. In other words, the future of the earth remains questionable in the hands of politicians, who should take some decisions for a better tomorrow. In this article, we try to discuss the global and regional perspectives on global warming and measures to control global warming.
Global Warming, Climate Change, Global and Regional Perspectives
The presence of greenhouse gases is important in the atmosphere. But problem is that their amount in the atmosphere is increasing day by day. Scientists conclude that the temperature of the earth is increasing at the rate of 0.2°C per decade. In the 20th-century earth’s average temperature has risen 0.5°C. In our country, 700 crore tonnes of carbon dioxide gas emit out into the atmosphere every year. In India, the emission of CO2 has not been stopped. In 1990 it was 0.68 megatonnes which increased up to 1015 mega tones in 2002.
Thus the greenhouse gases are increasing fast. By global warming, we mean a rise in the average temperature due to the concentration of thermal energy in the atmosphere. Due to industrialization, there has been an increase in the amount of carbon dioxide which has given origin to the greenhouse effect. The thermal energy coming out of the earth’s surface cannot escape from the atmosphere. As a result, there is an increase in the temperature of the earth. In addition to carbon dioxide, methane, chlorofluorocarbons, and nitrous oxide are also responsible for the greenhouse effect.
Due to global warming sea-level rise would immediately threaten that large fraction of the globe living at sea level. Nearly one-third of all human beings live within 36 miles of a coastline. Most of the world’s great seaport cities would be endangered. Some countries-the Maldives Island in the Indian Ocean, islands in the Pacific oceans would be inundated. Heavily populated coastal areas such as in Bangladesh and Egypt, where large populations occupy low-lying areas, would suffer extreme dislocation. Warmer oceans would spawn stronger hurricanes and typhoons, resulting in coastal flooding, possibly swamping valuable agricultural lands around the world. Food supplies and forests are adversely affected. Changes in rainfall patterns would disrupt agriculture. Warmer temperatures would shift grain-growing regions polewards. Human health would be affected. Warming could enlarge tropical climate bringing with it yellow fever, malaria, and other diseases. So global warming may be the greatest challenge facing humankind.
Global and Regional Perspectives
Increased Sea Surface Temp. (SST) by 2°C could increase cyclone intensities by 20 percent, wind gust velocities by 11 percent, and wind loadings on structures by 20 percent. An increase of SST by 2° C. could mean an increase in cyclone frequency at the order of 2 o 3 times. A modest sea level rise could have great implications particularly for low-lying islands and coastal nations in the form of increased rates of coastal erosion and salt intrusion into groundwater systems. These in turn have secondary impacts on agriculture, water resources; commercial and residential property, energy systems, transportation systems, and so on. One meter rise of sea level would require expenditures of between US$ 10 and US$100 billion to maintain threatened beaches and coastal areas on the eastern coast of the USA.
In the Netherlands, existing dikes and other protection against storm surges will have to be reinforced at a cost of US$3 to 8 billion, respectively for a 70 to 200 cm sea-level rise. In Bangladesh, the combination of sea-level rise and subsidence of the river system could flood the delta region and threaten anywhere between 8 to 24 million people. A rise in sea level of 0.5cm would also severely affect small oceanic Islands, Particularly the low reef islands and atolls of the Caribbean and the Pacific Ocean. Many regions, particularly the most overpopulated ones, could suffer from severe drought, famine, and shortages of essential raw materials. The net global impact may be a drastic lowering of standards of living, physical wellbeing, and even substantial loss of life.
The rapid change in temp probably has a more severe impact on forest ecosystems and on irrigated agriculture in the semi-arid areas of the mid-latitudes (e.g. The American Midwest) Which will suffer from higher temperatures and increased drought in summer. The sea level has probably already risen 7-17cm during the 20th Century. On the basis of the observed changes it is assumed that the predicted global warming of 1.5°C to 3.1°C would lead to a sea-level rise of 20-165cm, the results would be the erosion of beaches and coasts and land-use changes particularly in coastal and river regions.
Wetland loss, increased frequency, and severity of flooding, damage to port facilities are some of the important effects. In an extremely pessimistic scenario, a temp, rise of 20 to 40^’C due to an increase in atmospheric C02 to 600PPM or more would cause the polar ice caps to melt sufficiently to raise the sea level of the major oceans by 5 meters or more.
Due to global warming, many species may not successfully adapt to changing habitats or migrate to new ones. Some may become extinct, whereas others may survive only in reduced numbers and range. Effects of global warming on individual species will be greatest on plants, which are directly affected by temperature and rainfall because individual plants like animals cannot move from one place to another as climate and habitats change. According to Margaret Davis of the University of Minnesota the four species of beech, birch, hemlock, and sugar maple trees would have to shift approximately 500kms north to remain in a suitable climate and habitat.
Davis says beech forests would disappear from the southern United States due to global warming; similarly, Davis Predicts sugar maple trees now growing from the great lake region of southern Canada to Tennessee, would migrate north along both sides of Hudson Bay. According to Daniel Botkin of California University shifting forest ranges would also affect animals such as Kirtland’s warbler, a critically endangered bird that breeds only on the sandy soils of Michigan’s Jack Pine forests. If the pine retreats north into Canada, the warbler will also follow.
According to Dennis Murphy of Stand ford University (USA) if the earth warms by 3°C the Western United Stated will lose 44 percent of the normal species, 23 percent of the butterfly species, and a somewhat smaller percentage of the bird species that reside there. Vera Alexander, director of the University of Alaska’s Institute for Man rise sciences in Fairbanks notes the direct relationship between Primary nutrients, food production, and the viability of many fish and marine mammals in Arctic Waters. According to Alexander if global warming melts the polar sea ice, the number of microscopic organisms would be reduced, and the marine animals they support would probably suffer as well.
Less sea ice would also affect seals that breed on the ice and polar bears which hunt and travel on the ice. Daniel Rubenstein a Princeton University biologist, argues that a hotter, drier Africa will force elephants to search further for food. Warmer conditions at high latitudes could lead to reduction in the area extent of boreal forests and to a poleward shift in their boundaries. A high rate of warming of 0.8°C to 1°C per decade will have major impacts on the mid-latitude temperature forests in the Northern Hemisphere and large-scale forest dieback between 2000 and 2050 is expected. Changes in climatic conditions would destabilize the unique climate and nutrient cycling systems of tropical forests.
Due to global warming, the increased severity and frequency of droughts such as experienced during 1986-87 and 1987- 88 will pose the largest threat to Canadian agriculture. Due to Global warming in the Arctic, the tree line is expected to move slowly northward at the rate of approximately 100 km per 1°C of warming. Drier climates in Southern Canada could also affect tree growth and significantly increase the risk of forest.
Ranjeet Singh Budania
Assistant Professor, Dept. of Geography, Govt. College, Taranagar (Churu), India