In 2015, for example, scientists said that an ongoing drought in Californiaâthe stateâs worst water shortage in 1,200 yearsâhad been intensified by 15 percent to 20 percent by global warming. They also said the odds of similar droughts happening in the future had roughly doubled over the past century.
Definition: Birth rate is the demographic measure of the rate at which children are born. The most well known is the crude birth rate, which is the number of births that occur each year per 1,000 people in the midyear population. It is called âcrudeâ because it does not take into account the possible effects of age structure.
The fertility rate measures the number of births occurring per 1,000 women between the ages of 15 and 44 in a particular year; birth rates refer to this measure within particular age groups.ge-specific birth rates are defined as the total number of births per 1,000 women in a specific age group (between ages 15 and 44). 2 Data for estimates before 1980 are based on the race/ethnicity of the child, from 1980 on estimates are based on the race/ethnicity of the mother.