Ask A Scientist

How many people are alive?

Asked by: Jaime Fidler-Young
School: St. James Middle School
Grade: 5
Teacher: Mrs. Walter
Hobbies/Interests: Swimming, school, friends, family, scrapbooking, singing with American Idol, sports, reading, piano, writing, travel, cooking and shopping.
Career Interest: Oral Surgeon

Answer from Michael A. Little

Distinguished professor of anthropology, Binghamto

Research area:
Human adaptation to the environment

PhD School:
Pennsylvania State University

Swimming, choral singing, antique toys and books

Wife, Adrienne, and two grown children

Web page address:

Human beings have increased enormously during the past century, so that we now number about 6.6 billion people throughout the world. This is all the more remarkable when we consider that our population has more than doubled in the past 50 years. At this time, the world population is growing at a rate of about 180 new people per minute or 43 million new people per year (calculated as babies born minus people dying). These numbers are difficult to imagine, except you might think of this number as about 4 times as many new people per year on the earth as already live in New York City! Predictions are that the world population will increase to about 9 billion people in the next 40 years. If this seems like a lot of people - it is. And it is probably too many for the earth to handle very well. Fortunately, the speed with which we are increasing is slowing down a bit and eventually our growth in numbers will level off and stop. But this may take one or two hundred years, and by that time our population may be twice what it is now (12 or 13 billion people). There are a number of problems that occur because there are so many people on the planet. First, we humans need space to live and large numbers of people take space away from other animals and plants. Lots and lots of plants and animals are becoming extinct (dying out) because humans are taking their spaces. These losses of other organisms contribute to imbalances on the earth, such as loss of forests, which can be very harmful to the health of the planet. Another problem is in feeding so many people. We are running out of good farming land to grow crops to feed all of the people on the planet. Also, fish and other animals from oceans are decreasing in numbers as we harvest them for food in greater and greater amounts. These conditions, where there is limited food and other resources such as oil and other energy, lead to conflicts that often end in warfare between nations. Also, with so many people, we are accumulating a lot of waste and are polluting vast areas of the world. Finally, our burning of fuels, such as coal, oil, and wood, contribute to carbon dioxide levels (greenhouse gas) in the atmosphere which increase conditions of global warming. As the climate warms up, ice in the Antarctic and Greenland melts, sea level rises, and some of the coastal lands are flooded around the world. This leaves less land for more people and contributes to the crowding of people that we see in many parts of the world. So what is likely to happen in your future? There are some good signs for the future, particularly in the slowing down of world population growth. Parents are having fewer children in parts of the world where families were expected to be very large, and in our own country, as well. And there is increasing use of energy efficient devices (windmills, hybrid cars, fluorescent light bulbs) and recycling, all of which lower the use of fossil fuels (oil, gas, coal) and reduce carbon dioxide. These practices may also reduce pollution and global warming and resulting sea level rises. Humans are really not owners of the earth; we are stewards of the planet. That means we have a responsibility to take care of it so that it remains a good place to live. Too many people will prevent us from being good stewards of our planet.

Last Updated: 9/18/13