Objectives : At the end of the lesson you will be able to explain the
Let' s remind ourselves : The previous section introduced you to the Global atmospheric circulation. In the section it was said that the strength, directions and steadiness of the prevailing winds are crucial for the climate. Winds associated with atmospheric circulation lead to transports of heat and mosture from remote areas and thereby modifying the climate. It was also said that the change in the structure of the atmospheric circulation and its associated winds is an indication of climate change. This section will now explore the issue of climate change and its causes.
Before you proceed watch the following:
Before you proceed watch the following:
Climate change or global warming is an increase in average global temperature. The indications of climate change include the increased average ocean temperatures, widespread melting of snow and ice and the rising sea levels.
Causes of Climate change
Climate change is caused by an increase in the level of greenhouses in the atmosphere.
As the sun's energy hits the Earth, some of the sun radiation is reflected back to the atmosphere. The rest of the sun radiation is absorbed by the land and oceans.
Absorbed energy is then radiated upward from the Earth's surface in the form of heat. In the absence of greenhouse gases, this heat would simply escape to space, and the planet's average surface temparature would well be below freezing.
The greenhouse gases absorb and redirect some of this energy downward, keeping heat near Earth's surface, creating the greenhouse effect.
As the concentration of the heat trapping greenhouse gases increase in the atmosphere, Earth's natural greenhouse effect is enhanced causing surface temperature to rise.
Causes of Climate change
Climate change is caused by an increase in the level of greenhouses in the atmosphere.
As the sun's energy hits the Earth, some of the sun radiation is reflected back to the atmosphere. The rest of the sun radiation is absorbed by the land and oceans.
Absorbed energy is then radiated upward from the Earth's surface in the form of heat. In the absence of greenhouse gases, this heat would simply escape to space, and the planet's average surface temparature would well be below freezing.
The greenhouse gases absorb and redirect some of this energy downward, keeping heat near Earth's surface, creating the greenhouse effect.
As the concentration of the heat trapping greenhouse gases increase in the atmosphere, Earth's natural greenhouse effect is enhanced causing surface temperature to rise.