Forests and oceans as carbon sinks
Forests and oceans as carbon sinksSOURCES:
1) The amount of carbon dioxide in our atmosphere has been increasing rapidly over the last few decades and continues to do so.
2) Historically, the trends in increase of carbon dioxide started in the late 1700's. This was the approximate time of the Industrial Revolution. At this time, the carbon dioxide concentration was around 270 ppm (pounds per million). Concentrations grew very slowly from this time until the twentieth century. But in the last century, especially in the last fifty years, carbon dioxide levels have grown rapidly. It is presently around 350 ppm.
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4) The Antarctic ice sheet provides a long record of carbon dioxide concentrations. This is done by examining tiny bubbles of air in the ice core at different levels below the present ice surface. The deeper layers in the ice core correspond to times in the more distant past. The air bubbles can be analysed for the relative abundance of carbon dioxide to estimate atmospheric carbon dioxide levels at times extending back 160 000 years. Through the ice sheet, we know that 160 000 years ago, carbon dioxide concentrations were about 180 ppm and have presently exceeded 350 ppm.
5) There are mainly 3 major sources of carbon dioxide presently and historically. They are industrial activity, land use change and cement plants. The carbon dioxide from industrial activity mainly comes from fossil fuel burning and is by far the most abundant of sources. The carbon dioxide from land use change comes mostly from deforestation which occurs mostly in Brazil, Indonesia and Columbia. The last major source of carbon dioxide in the earth's atmosphere is the emission from cement plants. Carbonaceous material used for making cement releases significant amounts of carbon dioxide. This source is fairly large since cement is used for roads, bridges, buildings and powering and manufacturing plants.
SINKS:
1) A carbon dioxide sink is a storage reservoir that increases in size, and the carbon dioxide sink size or strength is the rate that the storage reservoir grows.
OCEANS AS CARBON DIOXIDE SINKS:
1) Oceans can regulate carbon in three different ways: by physical processes, chemical processes, and biological processes. Physical processes include the movement of carbon by ocean circulation from one location to another. This process is referred to as advection. Another physical process is the diffusive mixing of water from one vertical level to another. On the other hand, chemical processes transform carbon among different molecular forms.
Biological processes include the production and decomposition of organic matter, which are confined to the upper layer of the ocean where photosynthesis can occur. If biological material remains near the surface, it will continue to cycle with the atmosphere. Carbon, such as in the form of phytoplankton that thrive in the surface water of the ocean, are eaten by small fish...
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