The most serious environmental emergences which we have to face today involve global warming.
It means that the temperature of the earth and ocean increase gradually. It is the result of the build up of certain gases which make the atmosphere hotter. These heat-trapping gases are also called greenhouse gases.
Although carbon dioxide is said to be the cause of more than 60% of global warming, there are other substances which cause global warming as well, including methane, chlorofluorocarbons, and nitrous oxides. Did you ever asked yourself why the earth is heating up? Some may say it is a natural phenomenon, others may claim that man made the changes. As a matter of fact, natural causes and human activities are the factors which influence global warming.
Studies claim that billion years ago, long before man exists, there is already a warming of the planet. One of the natural cycles which believed to cause the rise of temperature is the sunspots cycle. For instance, explosions of the sun's surface produces heat which can hit the earth causing intense temperatures. Another natural factor believed to affect global climate is the earth orbit and tilt.
Any changes of the earth orbit can cause the planet to move closer or farther from the sun. Therefore it is one of the culprits for global warming. Evidence proved that plate tectonics caused poles to be isolated from warm ocean currents. Thus it can affect our climate. Furthermore, another natural factor for global warming is the release of methane gas from wetlands and arctic tundra. One example of greenhouse gas involved in global warming is methane.
Although greenhouse gases occur naturally to keep the Earth temperature stable to maintain life, human activities increase the concentration of these gases in the atmosphere. As concentration of greenhouse gases in the atmosphere increases, the atmosphere is capable of absorbing more heat. As a result, the earth tends to warm up. In this case, man is believed to be a factor for global warming. The rise of Industrial Revolution dramatically increases the concentration of Carbon dioxide and other greenhouse gases in the atmosphere at rates much faster than the earth can cycle them.
Transportations, factories, electricity from coal-fired power plants produce carbon dioxide and other heat-trapping gas in the atmosphere. Cutting down trees is another significant source of greenhouse gases, because fewer trees mean less conversion of carbon dioxide to oxygen. In addition, research shows that burning wood and fossil fuels such as gas, coal, and oil contributes carbon dioxide; methane is released from livestock and coal production; and agricultural and industrial processes produces nitrous oxide.
