Question

1.a.Discuss briefly the key differences between climate change and climate variability.
(25marks)
b.Write a short essay on climate sub-systems.
(25marks)
2.a.Write an essay on Global Warming.
(25marks)
b.Write notes on the Greenhouse Effect.
(25marks)

Answer 1

1.a. Climate change is the change that occurs over long periods of time usually decades. It considers long term changes in the weather conditions of a particular region with respect to rainfall, temperature, windblow etc.. For example: Global Warming refers to an increase in the surface temperature of the Earth which is caused by burning of fossil fuels that releases carbon dioxide and other greenhouse gases into the atmosphere. Climate variations are the changes that occur over short range of time like a season, a month or an year. It is caused due to natural changes which effect the amount of incoming solar radiation.

1.b. Climate is the state of the atmosphere in the specified time period. There are six zones of climate. They are:

• Tropical moist climate: The mean temperatures are high in these type of climates. They are divided into three sub-types i.e. Tropical Wet, Tropical Wet and Dry, Tropical monsoon.
• Dry Climate: Evaporation exceeds precipitation in these areas. These are divided into two subtypes i.e. semiarid and arid regions
• Moist Climate with mild winters: Humid and mild winters. The major subgroups are Marine westcoast, humid subtropical and Mild mediterranean.
• Moist climate with severe winters: They experience snow for extended periods. There are two climatic subtypes i.e. humid continental and subarctic climate
• Polar Climate: They experience extreme cold with very less precipitation. They occur along the Arctic and Antarctic circles.
• Highland: Regions associated with high elevations usually have high diurnal temperature variations.

2.a. Global warming corresponds to the average increase in the Earth's surface temperature due to human activities that includes high industrialization and burning fossil fuels that release green house gases. It occurs due to the action of carbon dioxide and other pollutants released as a result of human activity that get trapped in the atmosphere absorbing the heat and solar radiation bounced off from the Earth's surface. usually the radiation that is bounced off from Earth's surface escapes into the space but is captured by the pollutants,that can last longer, in the atmosphere. Coal burning power plants that burn coal to produce electricity are the biggest polluters. As a result of the increase in heat, the polar ice caps are melting that rises the sea and ocean levels. As a result, the low lying areas get submerged in due course of time.  

2.b. Greenhouse effect is a process where the gases in the Earth's atmosphere trap the sun heat making the Earth much warmer. The gases that trap the heat are called green house gases. During the day, as the Sun shines, the Earth surface get heated up. during the nights, the Earth's surface cools down, it releases the heat into the atmosphere. This released heat is trapped by the greenhouse gases that keeps the Earth warm. Greenhouse effect can be reduced by the action of photosynthesis, where the green plants absorb carbon dioxide which is the major component of greenhouse gases, and giving out oxygen. Hence, they help in maintaing the balance of Earth.