Global Warming Global warming is the warming near the earth's surface that results when the earth's atmosphere traps the sun's heat. The earth is getting warmer. The changes are small, so far, but they are expected to grow and speed up. Within the next fifty to one hundred years, the earth may be hotter than it has been in the past million years. As oceans warm and glaciers melt, land and cities along coasts may be flooded.
Heat and drought may cause forests to die and food crops to fail. Global warming will affect weather everywhere, plants and animals everywhere, people everywhere; humans are warming the earth's atmosphere by burning fuels, cutting down forest, and by taking part in other activities that release certain heat trapping gases into the air. One major cause of global warming is the use of fossil fuels. Fossil fuels like coal, oil, and natural gas that were formed from the remains of plant material deposited during the earth's carboniferous period. We have known for only a few thousand years that coal, oil, and natural gas can be burned to provide energy. It was not until the mid-1800's, however, that we began to burn very large quantities of these fossil fuels.
It has been estimated that between 1850 and 1950, approximately sixty billion tons of fossil fuel were burned, mostly in the form of coal. More recently, the worldwide consumption of fossil fuel has increased dramatically. The world now burns at least five billion tons of fossil fuel each year. This means that we are adding between fifteen and twenty billion tons of carbon dioxide to the air every twelve months! As this carbon dioxide from burning fossil fuels enters the atmosphere, some of it is take up by photosynthesizing plants, and the oceans absorb some. But because we are burning so much fossil fuel at such a rapid rate, we are putting carbon dioxide into the atmosphere much faster than these natural process are taking it out. There is no longer a balance between the amount of carbon dioxide being added to the air and the amount of carbon dioxide being removed.
As a result, the concentration of carbon dioxide in the air is steadily increasing. Unfortunately, burning fossil fuels is not the only thing that we humans are doing to increase the amount of carbon dioxide in the atmosphere. In many parts of the world today, forests are being destroyed at an alarming rate. Enormous numbers of trees are being cut down, both to provide timber and to clear the land for farming or ranching. This destructive process is called deforestation.
In order to clear forests for agriculture, people cut down and burn all the trees in area. When the flames die down, nothing is left but acres of blackened, lifeless countryside. The fire destroys all the plants and kills or drives off the animals. Because there has been little attempt to replant trees in deforested areas, the world's forests are disappearing very quickly. In fact some experts predict that if deforestation continues at its current rate, all the world's rain forest could vanish within only a few decades. Deforestation makes the problem of the greenhouse effect worse in two ways.
When trees are burned, carbon dioxide is released into the air. Some researchers think that the large-scale burning of forests around the world adds at least one billion tons of carbon dioxide to the atmosphere each year. But deforestation does more than just add carbon dioxide into the air. To also eliminates countless numbers of carbon dioxide-absorbing trees from the environment. As fewer and fewer trees are left to take up carbon dioxide, the concentration of carbon dioxide in the atmosphere increases faster and faster. Much evidence exists showing that the climate changes in response to the greenhouse effect.
The degree of change depends on the degree of global warming. Even the lowest projected temperature increases for the coming decades, however, are expected to cause considerable climatic changes. The greater the increase, the more dramatic the changes. Some parts of the earth will warm more than other parts. Some parts may even become cooler.
Global circulation models have shown that warming will be faster near the poles than near the equator. Such changes will have a significant effect on weather patterns. There will be changes in precipitation, storms, and wind directions and so on. Rising temperatures are expected to increase tropical storm activity. The hurricane season in the Atlantic and Caribbean is expected to start earlier and last longer.
Storms will be more severe. Changing wind patterns will mean that the paths of the storms will be changed, too, making some regions more vulnerable to damage than they are today. Another major effect of global warming is the rising of seas. As the earth gets warmer, there will be a rise in the average water level of the oceans. Two factors will cause this rise: thermal expansion and melting polar ice caps. As water is heated, it expands, or increases in volume.
According to theory, global warming could cause thermal expansion of the ocean waters, which in turn would cause sea levels to rise. Thermal expansion is expected to account for as much as half of the increase in sea level over the next century. The rest will come from the melting of glaciers. Glaciers are large, thick masses of slow-moving ice that persist from year to year. They cover about a tenth of the earth's land surface. The vast ice sheets of Antarctica and Greenland account for most of this area.
Smaller ice caps are found in Scandinavia, Caff in Island, Iceland, and elsewhere. In addition, there are tons of thousands of valley glaciers that follow stream channels down mountain slopes. All together, glaciers contain about seventy-five percent of the available fresh water of the earth. Because global warming is expected to be greatest in polar and temperate regions, scientists expect the glaciers to melt more rapidly than they do today. An executive summary of a United Stations survey published in 1990 concluded that if worldwide "business as usual" continues, the resulting global temperature increased would produce mean sea-level rise of about twenty-five inches by the end of the next century. Other studies predict such increases will occur as soon as 2040.
Much depends on how fast the polar ice melts. If global warming accelerates and the ice melts faster than expected, ocean levels may rise as much as ten feet by 2100. In order to slow global warming, scientists estimate that we need to cut in half the amount of carbon dioxide that we now release into the air each year. There are at least three ways in which we can do this: by conserving energy, by reforesting the earth, by reforesting the earth, and by switching to renewable and alternative forms of energy.
A large portion of the energy sources we use comes from burning fossil fuels. Most power plants burn fossil fuels, especially coal, to generate electricity. Both natural gas and oil are widely used for heating homes, schools, and offices. Cars, trucks, motorcycles, and lawnmowers all burn gasoline, which is extracted from oil. Energy is one of the quickest ways to reduce the buildup of carbon dioxide in the atmosphere. If we really want to control the greenhouse effect and global warming, then people everywhere must learn to use energy more wisely.
This is especially true in the United States. Then U. S. consumes more energy than any other nation on earth and contributes one fifth of all the carbon dioxide that enters the atmosphere each year. Conserving energy means making changes in the way we live. It means walking or biking instead of taking a car.
Or, if you must ride, taking the bus or some other form of public transportation whenever possible. Conserving energy means turning off the lights, TV, and stereo when you leave the room. It means turning down the thermostat in your house in the winter and turning it up in the summer. Or better yet, try using fans instead of air conditioning in the summer months. You can help some energy by recycling paper, glass, plastic, and aluminum-it takes energy to make all of these products. When it comes to energy conservation, little things mean a lot.
Some of the changes we make in our lives in order to save energy may not be pleasant. It is hard to cut down on conveniences that we are accustomed to using all the time. In order to get people to conserve energy effectively; it may become necessary for governments to provide incentives to encourage them to do so. Serious efforts to conserve energy will have many benefits. Most importantly, energy conservation will reduce carbon dioxide in the atmosphere and slow the rate of global warming. It will also reduce the air pollution and improve the quality of the air we breathe.
Energy conservation would mean that we could not need to dig as much coal mines or import as much oil from foreign countries as we do now. Another thing we can do to help reduce the amount of carbon dioxide that accumulates in the air is to plant millions of new trees. This process is known as reforestation. Like other green plants, trees use carbon dioxide from the atmosphere. But remember that burning fossil fuels adds about twenty billion tons of carbon dioxide to the air each year; In order to remove that much carbon dioxide from the air each year, we would need to plant enough trees to cover an area roughly the size of Australia! It's not very likely that we would be able to do that. But reforestation on a smaller scale can at least help slow the buildup of carbon dioxide in the air and delay global warming.
Some industries are using reforestation as a way to make up for the carbon dioxide they are releasing into the air. Like conserving energy, planting trees is a way in which many people can become involved in helping to control the greenhouse effect and global warming. Reforestation is certainly not a "cure" for the greenhouse effect. But like energy conservation, it will help control problems while we are developing new energy sources that don't add carbon dioxide to the atmosphere. There is not getting around the fact that our world needs energy. But we cannot go on using fossil fuels as we are now without doing more and more damage to the earth and its climate.
Therefore it is very important that the world quickly find new energy sources that do not add carbon dioxide to the atmosphere. Solar, wind, and geothermal power are ideal choices for new energy sources. Energy harnessed from the sun, from winds that sweep across the landscape, and from that stored deep within the earth can be use to make electricity. All these forms are clean, safe, and renewable: they can never be used up like fossil fuels eventually will be. Unfortunately, the world cannot easily switch to using these renewable energy sources at this point. The technologies of solar, wind, and geothermal power have problems that must be solved before they can be used for large-scale production of electricity.
Cost is also a problem. Eventually, advances in technology should lower the cost of solar power and should also make other renewable energy sources more practical replacements for fossil fuels. It is very likely that solar, wind, and geothermal power can eventually be used to produce electricity we need for many things. But what about energy needed to operate cars and other vehicles that now run on fossil fuels One potential source of energy for transportation is alcohol fuel. Alcohol fuel is produced from plant materials such as corn. Alcohol fuel gives off few pollutants as it burns.
And although carbon dioxide is released in the burning process, alcohol fuel doesn't add extra carbon dioxide to the atmosphere in the way that fossil fuels do. This is because the plants used to alcohol fuel to take carbon dioxide out of the atmosphere while they are growing. Thus, there is a continual balance between the amount of carbon dioxide removed from the air by the corn plants and the amount that enters the air when the fuel made from the plants is burned. If we can reduce the greenhouse gases going into the atmosphere, we probably can slow the rate of global warming and climate. There are a number of things that we can do to prepare for the changes that are coming. If we act now, perhaps we can "soften the blow" of the greenhouse effect.
In the future, the weather cold change much more dramatically from year to year than it does now. As global warming alters habitats, many kinds of animals will be on the move, but all sorts of barriers will stand between them and a new place to live. To help animals get around these barriers, it might be necessary to set up migration corridors that connect natural areas with one another. Without human intervention, many kinds of plants also may not survive as the earth's climate changes.
Forests, in particular, may need our help. If climate changes come rapidly, few tree species will be able to spread into new areas fast enough to keep up with changing conditions. The greenhouse effect will affect all life on earth. It is a global, problem, one that must be faced by people everywhere. No nation acting alone will be able to slow the pace of global warming due to climate change. Our only hope of dealing with this enormous environmental problem is international cooperation.
But getting countries to work together is a very challenging task.