Population Explosion
At the very moment this article is being laid out, there are an estimated 6,457,707,023 people in the world. About 296,780,789 of them are living here in the United States. We say, "estimated" because these numbers from the U.S. Census Bureau's population clock are based on projections.

That's a lot of people. So many that, like us, you might be having a little difficulty really understanding a number that large. Let's try to put it in perspective.

Say you're 12 years old and you want to count to the number one billion. If you're able to count one number per second continuously without sleeping, you would be almost 44 years old by the time you reached one billion. Or think about it this way: One billion seconds is 31.7 years. Two billion seconds is 63.4 years. Five billion seconds is 158.5 years.


So, if all 6,457,707,023 people were gathered together so that you could count them, one by one, one second at a time, it would take more than 200 years to count them all. But trying to fit all these people in one place would take a lot of space. With everyone standing front-to-back and side-by-side, each individually taking up a space of two square feet, you would need something like five-and-a-half million NBA-sized basketball courts to hold all 6,457,707,023 people.

We've established that there are a lot of people on our planet. But, you may be wondering, "Why keep track of the population? Why do we care how many people there are on Earth? What's the big deal, anyway?" It actually is a really big deal. You see, the population is definitely a lot more than a huge number.

A rose by any other name...
It's important to know, when dealing with numbers in this range, that the term "billion" doesn't always mean the same thing. For example, in the United States and some other places, a "1" followed by nine zeros represents the number "one billion." However, in the United Kingdom, a "1" followed by 12 zeros represents "one billion."

National Scope
In a country as large as the United States, how is it possible to count each person residing within its borders? Since 1790, national census information has been taken every 10 years (in years ending in zero) because it is mandated by the U.S. Constitution under Article 1 Section 2. The information that the census tracks is very important. Over $100 billion in federal funds is given out each year for community programs and services, such as education programs, housing and community development, health-care services for the elderly, job training and more. Population information helps the government decide how to divide that money around the country.

The U.S. Congress uses the census totals to determine how many seats your state will have in the U.S. House of Representatives. And, states use the numbers to allocate seats in their law-making bodies. State and local governments use census information in other ways, too. Census totals help state and local officials plan and allocate funds for new school construction, libraries and other public buildings, highway safety and public transportation systems, new roads and bridges, location of police and fire departments and many other projects.

Census information helps health providers predict the spread of diseases. And when floods, tornadoes or earthquakes hit, the census tells rescuers how many people will need their help. Even businesses use census information. It's how they decide where to locate restaurants, shopping centers, movie theaters, theme parks, banks and more.

As you can see, all that we learn about ourselves by studying the population helps a lot. The U.S. population is more than just the number of people residing within this country. These numbers affect the very quality of our life. Not only are population studies significant here, they are vital worldwide.

Global Scope
There are people all around the world who devote their time to studying the population. The numbers tell us many things. For example, right now:

  • The world is at its highest population ever.
  • The rate of growth is more than 75% higher in less developed countries than that of more developed countries.
  • Our average life span is higher than that of our ancestors.
  • The number of young people is at an all-time high.
The population has a great impact on our environment, economic development, health issues and more. For example, let's consider population and the environment.

Each of our lives is tied to the Earth and the resources it provides us. The water (and other beverages) you drink, the food you eat, the air you breathe, energy powering our homes and schools, gas for cars and school buses - it's all part of nature's resources. Now let's think about the numbers. We're at our highest population ever and growing. We're living longer than ever before. The number of people under the age of 25 is at an all-time high. This all adds up to more and more people on Earth, using the resources it has to offer.

While you're reading this article, you are probably someplace where you can easily get some water. Because you can simply stroll down your school's hall for a cold refreshing drink, you might think that resources aren't limited. But they are. People are living without running water. Others are living without access to safe drinking water. And not all of these people are living in less developed countries. Some of them are living right here in the United States. Imagine walking several miles to collect water for your family, only to become ill from it. Water supplies are often contaminated. In fact, millions die each year because of contaminated water.

When you start looking at the population and the environment, it's easy to see how they are remarkably linked. You also begin to see links to other things like poverty, education, health and more. People from countries all around the world understand how important these connections are. For example, 191 member states of the United Nations are committed to fulfilling the Millennium Development Goals by the year 2015. Many of these goals are very closely tied to population issues. For example, they're working to rid the world of extreme poverty and hunger, provide primary education to everyone, improve maternal and child health and ensure environmental sustainability.

People living in developed countries like ours use resources much faster than we can replenish them. Think about deforestation, water shortages, and water and air pollution. Every time we build a new neighborhood or a new shopping center -- that has an impact. While it is providing needed shelter and access to foodstuffs and other materials, it's also taking its toll on the local environment. And this toll has a larger affect, worldwide. As we deplete our resources here in the United States, we look to other countries and their lands for more resources.

Try this:
Using this Web site (http://www.census.gov/popest/archives/1990s/popclockest.txt), find the U.S. population for the years listed below. Then figure out the population increase during each five-year span (for example, from 1995 to 2000, the increase was 19,321,724). Round each number up to the closest 1,000 and create a line graph using population versus the time increments. Do the same for world population, using the dates below and this Web site (http://www.census.gov/ipc/www/worldpop.html). Compare the graphs. Is there a noticeable trend? Now, find the mean, median and range for these population changes for the U.S. and the World populations.

Make two bar graphs (one for each person) using the information you found. Compare the graphs, noting how they are different.

WebQuest Exercise
Dates
U.S. Population Change
World Population Change
1950-1955
13,660,000
224,667,000
1955-1960
   
   
1960-1965
   
   
1965-1970
   
   
1970-1975
   
   
1975-1980
   
   
1980-1985
   
   
1985-1990
   
   
1990-1995
   
   
1995-2000