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Lessons > Feedback Effects > Step 1

So far we have considered only the impact of burning fossil fuels. But there are other human activities that influence the carbon cycle. One major factor is deforestation and land use. Currently, land use (for example, rice paddies) and deforestation outstrip reforestation by roughly 1 GT per year. If deforestation were to increase, perhaps due to increased burning of rainforests, carbon would be transferred first from terrestrial plants to the atmosphere and then through the rest of the carbon cycle as seen in Lesson 1.

Change the net deforestation rate and observe how that impacts the carbon cycle. Note that deforestation is expressed as GT of carbon released, not as a percentage rate of increase. Realistic deforestation estimates would remain less than 2 GT per year. Record what happens to the system at a steady net deforestation rate of 1.6 GT per year and answer the following:

1. By 2090, how has the terrestrial flora population changed? What is the carbon level in the soil and how does the carbon level affect the flora populations and species variety?
2. Compare this chart to the first one you made.
   1. In 2070, how are soil carbon levels different? In what ways will this difference in soil carbon level manifest itself?
   2. By 2070, how might the worldwide decomposer populations change? What effects could “business as usual” and the last rate of deforestation you selected have on human health?