Question

Problem 3

Recent studies have indicated that by 2030, more than a quarter of the Amazon rainforest could be without trees as a result of deforestation. The rainforest currently spans 670 million hectares (1 hectare= 2.471 acres or 10,000 square meters).

1. Determine the rate of deforestation between 2019 and 2030 assuming an exponential decline and a 25% reduction in rainforest area over this period. What is the sign of the rate you calculated, and what does it signify?

2. As the population grows, there is also an increased need for agricultural production. Cattle ranching has been the biggest cause of deforestation in the Amazon, accounting for approximately 80% of the current deforestation rates. Suppose cattle ranching is completely banned for the next 5 years, but that the remaining drivers of deforestation continue exponentially. How would this ban affect the year at which a quarter of the current Amazon’s trees have been depleted?

3. A cattle ranching ban could lead to increases in illegal deforestation methods such as logging and setting fires. Illegal deforestation would initially cost the government $8.5 billion per year in enforcement and mitigation. If these costs increase at a rate of 3% per year, compounded annually, how much money will be spent during the ban?

Human-caused deforestation, both legal and illegal, can sometimes lead to catastrophic unintended consequences such as the current widespread forest fires in the Amazon. How do you think the current forest fires might impact the 25% deforestation year you predicted in part (b)? Given that the model in part (b) did not account for possible unintended consequences, to what extent are these models helpful for predicting deforestation?

Answer 1