What is Climate Change and how human activities are causing Global Warming?

According to Oxford Dictionary,Changes in earth's weather due to changes in temperature, rainfall, wind patterns, increase in temperature of earth's atmosphere which is caused by gases partculary carbon dioxide, is called climate change.

According to United Nations Framework Convention on Climate Change (UNFCCC), The climate change may be direclty or indirectly attributed to human activities that change the composition of global atmosphere.

The results of climate change are global warming and ozone depletion. The retention of heat by the atmosphere is called Greenhouse Effect. It happens naturally but due to human activity, it is enhanced.

The greenhouse effect is natural activity. It is supposed to be happen even if there is no human being present on the planet. Without greenhouse effect, we could not live on this planet as the planet would be as cold as Mars and would be 33c colder.

The main causes of greenhouse effect are population growth, Chlorofluorocarbons(CFC's), burning of coal, wood, fossil fuel and deforestation. The gases which trap the heat in the atmosphere are called greenhouse gases. Examples are Methane, Nitrous Oxide, Carbon dioxide and water vapor.

There are some greenhouse gases like Fluorinated gases, which are only produced due to human activities.During the industrial process of semiconductor and aluminium manufacturing, these gases are emitted. Such gases have very high global warming potentials and some of them may have long atmospheric lifetime i.e. they can last for thousands of years. They got mixed in the atmosphere and are then easily spreaded. However, they can only be destroyed by sunlight in upper atmosphere.

The example of greehouse effect is like this. Suppose the car is parked in sunlight. The glass allows to let in sunlight. At the same time, the glasses prevent the heat from escaping. As a result the car heats up.

When sunlight passes through the atmosphere, 26% is scattered or reflected, 19% is obsorbed in clouds, gases and particles, 4% is reflected through spase and remaining 51% reaches the surface. This 51% energy is used in heating the ground, melting of snow and ice, photosynthesis of plants and evaporation of water.

According to report, around 6.5 billion metric tons of greenhouse gases in emitted in USA, which is 25% of the total world. Carbon dioxide can stay in the atmosphere for 100 years and methane lasts for 12 years. These gases continue to raise the temperature of the surface, they trigger the release of even more carbon dioxide and methane which are currently trapped in frozen permafrost and tundra soils, thus further increasing the temperature. Thus we can say warming begets more warming.

Ozone is made up of three oxygen items and is relatively unstable molecule. Ozone layer protects the earth from harmful ultraviolet radiation of the sun. Unfortuantely, this layer is being destroyed by CFCs and other human activities.

Due to depletion of Ozone layer, acute and chronic health of skin, eyes and immune system are resulted. The life cycle of plants is changed, thus whole food chain is disrupted.Many marine species are coming to end, like Phytoplankton, due to increased ultraviolet radiation. Wind patterns are changed which result in climate changes.

The summarized impacts of climate changes are rise in temperature, rising sea levels, change in precipitation, changing habitats of plants and animals, extreme weather conditions, food and water scarcity, ocean acidification and greenland melts.

So what can we do to reduce climate change? We can start using efficient vehicles; reduce vehicle use, efficient buildings,enhance the world's nuclear capacity, increase solar electricity and reduce global deforestation.