Global Environmental Problems

Spring 2006

Problem Set #5

Due: 8 March

1.

In chapter III of Harte, read problem 14 ("Approaching a Steady-State Population in China") and do exercise 3. Using the Excel spreadsheet I have provided, do exercises 6 and 8. The Excel spreadsheet contains Harte's model, with a provision for declining death rates.

2.

The population of Denmark is about 5 million; it has been and is expected to remain at about this level for several decades. Estimate the number of births and deaths in Denmark each year, without reference to any sources of data, based solely on common sense and stock-flow-residence time considerations.

Now look up the actual number of births and deaths in the most recent year available, using WRI, Census, PRB, or UN data. How does your guess compare with the actual numbers?

3.

Calculate your ecological footprint (in ha) using one of the various calculators available on the web. (You may use those listed here or any other you might find.) What is the human carrying capacity of the Earth, if everyone had your lifestyle? How might this calculation change over the next 50 years?

4.

Here is an Excel spreadsheet I wrote to implement a simple cohort-component model of the United States, using Census data from 1980 to 2000 and extrapolating to 2050 assuming an exponential decline in age-specific death rates.

A.

What will the U.S. population be in 2050 in fertility and immigration rates remain constant at the 2000-04 levels?

C.

The figures on the "immig" page include legal immigration only. It is estimated that net immigration, including emigration and illegal immigration, is roughly equal to twice legal immigration. Modify the spreadsheet accordingly. What is the U.S. population in 2050 if TFR remains constant at the 2000-04 level?