Chris+D.


 * TOPIC 5: Describe how climate can be influenced by human activities (eg. Greenhouse gasses, depletion of ozone layer) **

In many ways, the climate is changing and is linked with human activities. Humans are everyday using resources that have an effect on the Earth, whether they realize it or not. Human activites have been seen to cause more problems to global warming which assists the depletion of the ozone layer.

=__ Green House Gasses: __= A greenhouse gas (sometimes abbreviated as GHG) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the essential and fundamental cause of the greenhouse effect. The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface, energy is transferred to the surface and the lower atmosphere. As a result, the temperature there is higher than it would be if direct heating by solar radiation were the only warming mechanism.



Greenhouse gasses are made up of different gasses. In the Earth’s atmosphere, the most abundant gasses are water vapour, carbon dioxide, methane, nitrous oxide, ozone and chlorofluorocarbons. However, carbon dioxide seems to the most affecting trait on the Earth’s atmosphere.

Carbon dioxide (CO2) is the most important green house gas produced by human activities, primarily through the combustion of fossil fuels. Its concentration in the Earth's atmosphere has risen by more than 30% since the Industrial Revolution. If carbon dioxide concentration in the Earth's atmosphere were to increase, less radiation of from the Sun would be directed back into space leaving the Earth with a warmer atmosphere which affects the global climate.

So how would there be an impact on climate if the growth of greenhouse gasses would increase? The air we have around us will become warmer than it is now. The greenhouse gasses are trapping thermal energy into the atmosphere. Less heat would be able to leave the earth, so temperatures would increase. As the warm air traps more water vapour, the air would also become humid. Climates will be greatly altered. Although temperatures rise, so will the colder temperatures. The temperatures in the cold side will become more colder as well, even though it is stated as "global warming" it affects the cold climate.

=__ ﻿The Ozone Layer: __= The ozone layer is a layer in the Earth’s atmosphere (located at the bottom of the stratosphere) that contains high concentrations of ozone. This layer absorbs much of the ultraviolet radiation from the Sun. 97-99% of the Sun’s high frequency ultraviolet radiation is absorbed by this layer. Ultraviolet radiation is harmful to life on Earth.

Ozone affects climate, and climate affects ozone. Temperature, humidity, winds, and the presence of other chemicals in the atmosphere influence ozone formation, and the presence of ozone, affects those atmospheric components. They go hand in hand, and both affect each other. Ozone's biggest affect on the climate would be the alterations of the temperature. The more ozone in a specific area of air there is, the more heat it keeps into the Earth.

So what affect would the climate have if the ozone layer is depleted? Even though the ozone layer isn't a big impact on the changes of the climate, it still plays a supporting role. Strong UV rays need to be blocked, and the shrinking of the ozone layer would greatly allow more of these harmful rays in. The Earth would be exposed more, and temperatures will rise. For example, the glaciers would melt causing a difference in the waters and affect the water cycle.



To conclude, humans have very much assisted these phenomenas that have been affecting our climate. With the excess amount of assistance from us, our climate will change over the years to come.

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Denny Ha comments: very photogenic and explained a lot.