In 2011 the human population of Earth reached 7 billion (see link below)
For an estimate of the current population visit census.gov
Key terms – Births
Crude Birth Rate (CBR) – The number of births, per 1000 people in a population.
Total Fertility Rate (TFR) – The number of children a woman is expected to have during her lifetime, based on current birth rates.
See the CIA World Fact Book for data on total fertility rates.
Key terms – Deaths
Crude Death Rate (CDR) – The number of deaths per 1000 people in a population.
Infant Mortality Rate (IMR) – The number of deaths of children <1 yr old per 1000 people in a population.
Child Mortality Rate (CMR) – The number of deaths of children <5 yrs old per 1000 people in a population.
Other key terms
Natural Increase Rate (NIR) = Crude Birth Rate – Crude Death Rate
Life Expectancy – The number of years that the average person, born in a given place may expect to live. Read this article from the BBC about how life expectancy is changing in some countries
Population momentum – Population Momentum from Britannica
For population statistics, take a look at: Gapminder.org
This Factors influencing Birth & Death Rates sheet outlines some of the reasons behind changes in birth & death rates.
One of the factors influencing fertility rates in different countries is the infant mortality rate. This link provides more detail.
Hans Rosling talks about Population momentum, a key issue in population growth.
Professor David Suzuki speaks about the dangers of overpopulation:
The importance of birth rate: