GEO1

We have read in chapter 3 of the textbook about the composition of the modern atmospheric gases of the Earth.  Current discussions about "global climate change" or "global warming" revolve primarily around the issue of human caused emissions of the greenhouse gas Carbon Dioxide (CO2) to the atmosphere.  Present levels of Carbon Dioxide (CO2) in the atmosphere are about 401 parts per million or at 0.04% of the Earth's atmospheric gases.  First, explain how if Carbon Dioxide (CO2), which is such a tiny percentage of the atmosphere, can be considered to be such a huge factor in warming the globe.

Secondly, there are naturally caused emissions of Carbon Dioxide (CO2) into the atmosphere from land and ocean plants, through global gross primary production and respiration.  Current estimates are that the natural flux (back and forth) of Carbon Dioxide (CO2) with the atmosphere are about 210 gigatons annually and human caused emission amount to about 8 gigatons of Carbon Dioxide (CO2) into the atmosphere annually (see illustration below).  Explain how, with the relatively small amount of human contributed Carbon Dioxide (CO2) (compared to the natural contribution of Carbon Dioxide (CO2) into the atmosphere), it is believed that the global warming or climate change problem is driven primarily by human activity.

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