The formula for doubling time is: 

Since the population grows by 4% every 5 years, we must divide these two numbers to find the annual population growth. 

Thus:

So, using this number in our equation, 

Our answer rounds closest to 88 years. 

There are two worldview extremes, the Deep Ecology and the Western worldview. Most people’s worldviews lie somewhere in between these two extremes. The Deep Ecology Worldview considers humans as no more important than other species and believes that all life has intrinsic value. The health of the environment is of the highest priority and humans should make sacrifices to protect it.

The continent of Asia hosts the majority of the Earth's population, at roughly  billion people,  of the total human population. In order to put this into perspective, it has been calculated that for every five people in the world, three live in Asia. 

The formula for the national population growth rate is:

We can substitute in the provided values in order to determine the population growth:

In his seminal work An Essay on the Principle of Population, Thomas Malthus theorized that eventually the human population would be halted by either famine, disease, or both. While his estimates on when this would occur proved dramatically incorrect, his work was very influential, and he has been studied by such critically important figures as Charles Darwin and Alfred Russel Wallace.

All of these can potentially influence the growth of human population. When people have access to more medical care, they both live longer and have higher rates of survival. Religions that oppose the use of contraceptives can also influence the size of a population; they are often found in areas or countries experiencing higher rates of population increase. In societies where women have access to more education, they are less likely to become pregnant at a young age, and also likely to have fewer children than women who do not have access to similar educational opportunities.

To calculate the city population for the following year, we take the initial population (20,000 people), add the annual rate of natural population change, add the number of immigrants and subtract the number of emigrants.

Now, we need to multiply this percentage of of population change by the original population size (20,000 people).

The population will naturally grow by 360 individuals. Now, add these individuals, subtract emigrants, and add immigrants to to the starting population size in order to calculate the new population for the next year.

Shelterbelts do fix carbon and some trees do fix nitrogen, but the dominant ecological benefit is their limiting of wind-caused soil erosion. Shelterbelts mimic a forest ecosystem by diverting wind currents away from soil that is often exposed by tilling.

Tilling has the benefit of increasing permeability of the soil for water and creating favorable conditions for young seedlings. No-till farming does not have these benefits, but it does reduce the risk of soil erosion because tilling generally destroys preestablished root systems.

Mulching can actually provide habitat for slugs, while removing mulch and topsoil puts your fields at serious risk of soil depletion and eventual erosion. Flooding your fields is also ineffective and could jeopardize your existing crops (and soil health for that matter!). Finding and squishing every single pest might put a small dent in the crops lost, but how much is your time worth? Mixed cropping is the best option, because many pests are specialists and feed off certain crops (leafy greens, drupes, etc.). Some of your crops will suffer but not all of them.