Causes of Environment change : Greenhouse Phenomenon

 

Causes of Environmental Changes

There are many causes of environmental changes on Earth. Natural events cause changes in climate. For example, large volcanic eruptions release tiny particles into the atmosphere that block sunlight, resulting in surface cooling that lasts for a few years. Variations in ocean currents which can also change the distribution of heat and precipitation. Over longer time spans, tens to hundreds of thousands of years, natural changes in the geographical distribution of energy from the Sun and in the amounts of greenhouse gases and dust in the atmosphere have caused the climate to shift from ice ages to relatively warmer periods. On a longer timescale the presence of life on Earth has changed the environment of the planet radically, transforming a predominantly reducing atmosphere made up of methane and ammonia to today's oxygen-rich gaseous envelope.

Human activities can also change the environment. Orbiting satellites have photographed the transformation of deserts into productive agricultural areas. Conversely, satellites have tracked the advance of deserts (desertification) and the loss of forests (deforestation) as a result of human activity. One root cause of desertification and deforestation is the use of wood as the basic source of energy, with the consequent loss of trees and degradation of the soil. Desertification affects about one-sixth of the world's population and affects 70 percent of all dry lands, amounting to 3.6 billion hectares (8.9 billion acres), or one-quarter of the total land area of the world. let see these causes of Environment changes in detail .

The Greenhouse Phenomenon

In addition to desertification, changes caused by human activities include recent increases in the atmospheric concentrations of both greenhouse gases and sulphate particles which are also known as "aerosols". Greenhouse gases such as carbon dioxide cover the atmosphere's "infrared window," and trap heat. Data from satellites can trace changes in the globally averaged surface temperature of Earth and can be used to predict temperature changes in the future. According to some models, if current trends continue, the amount of carbon dioxide in the atmosphere will double during the twenty-first century, and the average rate of warming of Earth's surface over the next hundred years will probably be greater than it was at any time in the last 10,000 years. The current best estimate of the expected rise of globally averaged surface temperature relative to 1990 is 1°C to 3.5°C by the year 2100, with continued increases thereafter.

 Because seawater expands when heated and some glacial ice will melt, the global sea level is expected to rise a further 15 to 95 centimeters (6 to 37.5 inches) by 2100 as a result of global warming. Since 1978 satellite technology has been used to monitor the vast Arctic Sea ice cover on a routine basis. In 2001 a joint U.S.-French oceanography mission, Jason 1, was scheduled to be launched to monitor world ocean circulation, study interactions between the oceans and the atmosphere, improve climate predictions, and observe events such as El Niño. You all be thinking what is El Niño?

What is El Niño anyway?

El Niño is a condition that sometimes occurs in the Pacific Ocean, but it is so big that it affects weather all over the world.

Weather depends a lot on ocean temperatures. Where the ocean is warm, more clouds form, and more rain falls in that part of the world. In the Pacific Ocean, near the equator, the Sun makes the water especially warm on the surface.

Normally, strong winds along the equator push the warm surface water near South America westward toward Indonesia. When this happens, the cooler water underneath rises up toward the surface of the ocean near South America.

However, in the fall and winter of some years, these winds are much weaker than usual. They actually blow the other way (toward South America instead of Indonesia) in October. So the warm surface water along the equator piles up along the coast of South America and then moves north towards California and south toward Chile.

Many fish that live in the normally cooler waters off the coast of South America move away or die. The fishermen call this condition of warm coastal waters and poor fishing "El Niño" meaning "the Christ Child," because in the occasional years it comes, it comes at Christmas time.

In El Niño years, lots of rain clouds forms over this warm part of the ocean. These clouds move inland and dump much more rain than usual in South and Central America and in the United States. Meanwhile, other parts of the world can suffer drought. Weather patterns all over the world may be unusual, making lakes out of deserts and charcoal heaps out of rain forests.

That's all for today in the next week we will see few more reasons of environment changes before signing off the question for today is 

What are the actions that can help to reduce global warming ?