Prewrite 2

Alam, S. M. "Greenhouse Gases." Pakistan & Gulf Economist 31.13 (2012): 64-7. ProQuest. Web. 21 Apr. 2013.
Natural ecosystems can store 20 to 100 times more carbon dioxide per unit area than agricultural systems. Both deforestation and natural land-use change reduce the amount of standing plant mass or biomass found on the Earth's surface.

"Global Warming and Carbon Dioxide through Sciences." ScienceDirect.com. N.p., n.d. Web. 21 Apr. 2013.
Carbon dioxide is a naturally occurring gas, a by-product of burning fossil fuels and biomass and a result of land-use changes and other industrial processes. It is the principal anthropogenic gas that is thought to affect the Earth's radiative balance.

"On the Global Warming Problem Due to Carbon Dioxide." ScienceDirect.com. N.p., n.d. Web. 21 Apr. 2013.
The production of carbon dioxide will form a blanket in space that will reduce the fossil fuel production on the earth.

"Carbon Dioxide Pollution Helps Weeds Thrive, Lowers Impact of Herbicides." Corn and Soybean Digest (2011): n/a. ProQuest. Web. 21 Apr. 2013.
Atmospheric carbon dioxide has increased greatly in the past two decades because of the burning of fossil fuels and changes in land use. Preindustrial carbon dioxide levels were rated at 280 parts per million (ppm), while 2005 levels reached 379 ppm.

Carey, John. "GLOBAL WARMING: Faster Than Expected?." Scientific American 307.5 (2012): 50-55. Academic Search Complete. Web. 21 Apr. 2013.
Staying below two degrees C would require limiting the level of heat-trap-ping carbon dioxide in the atmosphere to 450 parts per million (ppm), up from today's 395 ppm and the preindustrial era's 280 ppm.