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.
Usually it makes more sense to use the per capita birth or death rate. This means the average births or death per individual. The variables used for per capita birth/death rate is lowercase b and d. For example, in a population of 50 with a birth rate of 20, the per capita birth rate would be 20/50 or .4.