Global Birth Rate: approximately 45 births per 10 seconds
Global Death Rate: approximately 18 deaths per 10 seconds
Global Net Gain: approximately 27 persons per 10 seconds
At this rate, it takes a bit over 5 hours to experience a net gain (births minus deaths) equivalent to the population of Corvallis (~50,000). This also means a net gain of about 85 million people per year, globally, which is about equal to the population of Germany and is approximately 1/4 (27%) of the current population of the US! This is equivalent to adding a Los Angeles to the world's population every two weeks, or adding one Germany each year.
As we will see later, most of the annual increase in global population comes from a handful of countries, including India, China, Pakistan, Bangladesh, and Nigeria.
The current world population (as of mid-2013) is a bit over 7 billion people (7.137 billion, to be more precise). We crossed the 7 billion mark in the autumn of 2011.
We crossed the 6 billion mark in the autumn of 1999.
We reached 5 billion in 1987.
In 1975, were 4 billion.
Thus, for three periods now, we have added a billion peole in about 12 years. (We've added more than 2 billion people in the years I've been teaching BI 301!! [I am old, but not THAT old!])
By contrast, it took from the beginning of human time until 1850 to gain our first billion.
UN population experts predict (2013 predictions) that we'll be about 9.7 billion by 2050 -- that would be an increase of about 37 % above our population in 2013...... Importantly, 90-95% of the projected increase is expected to occur in the lesser developed countries ("LDC's") of the world, many of which are already feeling the pressures of population and resource limitation acutely.
WHAT HAS CHANGED? -- Why are we growing so fast now, when for so many centuries the human population grew so slowly? To answer this, we must look into human history a bit. Along the way, I'll define several parameters relating to population that will help with understanding how we got to be where we are, and that will also help us in understanding the current human population situation (click on Current Growth to jump to notes on that topic).
You can see real time population counters at these web sites -- it is pretty scary to see the speed with which the numbers click up.....
(Click ">>" box at the bottom to move to the next section (on how to calculate population growth rates) now; "<<" box to move to preceding section, "Contents" box to return to master directory for the BI301 web site. "Navigate " gives general reminders on how to do that.
Page maintained by Patricia Muir at Oregon State University; last updated Nov. 5, 2013.