Geography (Year 12)
Global climate change
Climate change refers to short-term and long-term shifts in temperature and weather patterns that result in earth temperature changes. These shifts may be natural, but in the last 200 years, human activities have increased the rate at which it is changing; this is primarily due to the pruning of fossil fuels( coal, oil, gas etc.), which produce heat-trapping gases.
Spatial distribution of the world's rainfall and temperature patterns.
The Earth's yearly average precipitation is 100cm, distributed across the globe unevenly. The regions with the highest rainfall are Southeast Asia's equatorial zone and monsoon area. The latitudes in the middle of the Earth sustain moderate amounts of precipitation compared to desert regions of the subtropics and around both poles. If the surface of the Earth were perfectly uniform, the long-term average rainfall would be distributed in prominent latitudinal bands. Even so, the situation would be challenging with the pattern of which the global winds, the distribution of the land and the presence of mountains. Due to this rainfall resulting from the increase and cooling of moist air, heavy rain areas indicate rising air.
In contrast, deserts occur when the air warms up and dries during the incline. In the subtropics, trade winds bring a generous amount of rain to the continents' east coast while keeping the west coast dry; an example would be an Australian summer in the last couple of years. In high latitudes, the west coasts experience more rainfall than the east coast of the continents. Rain usually is abundant on the windward slopes of mountain ranges but sparse on the lower sides of the mountain ranges. Within the equatorial belt, trade winds from both hemispheres converge to give a rise in the general upward movement of the air, intensifying the likelihood of a tropical storm. A tropical storm produces weighty rains in the Caribbean, the Indian and southwest Pacific oceans, and the china sea; this also increases the chances of thunderstorms in the adjacent land areas.
Critical elements of the following natural systems and how they influence the Earth's climate:
Heat budget, including the greenhouse effect: With the natural greenhouse effect, the energy budget is balanced as thermal radiation is re-radiated towards the ground, trapping thermal energy and warming the Earth. However, with humans' enhanced greenhouse effect, the Earth's energy budget is shifted to an imbalance. (IMAGE)
Hydrological cycle: Also referred to as the water cycle, this involves the continuous circulation of water in the Earth-Atmosphere system. This cycle is a constant water movement from the ground to the atmosphere. Also described as the biogeochemical cycle that describes the continuous movement of water on, above and below the surface of the Earth. (IMAGE)
Carbon cycle: is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of Earth. Carbon is the main component of biological compounds and a significant component of many minerals, for example, limestone. (IMAGE)
Atmospheric circulation: is the large-scale movement of air and, together with ocean circulation, is how thermal energy is redistributed on the surface of the Earth. The Earth's atmospheric circulation varies from year to year, but the large-scale structure of its circulation remains relatively constant. Even with disruptions like weather fronts and storms, there is a consistent pattern to how air moves around our planet's atmosphere. This pattern, called atmospheric circulation, is caused because the Sun heats the Earth more at the equator than at the poles. It's also affected by the spin of the Earth. (IMAGE)
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