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.
Abbreviated BMR. birth rate the number of live births in a geographic area in a defined period, usually one year, relative to some specified population. For the crude birth rate, it is the average total population or the midyear population in the area during the period.he cause-specific death rate is the ratio of the number of deaths due to a specified cause to the average total population. Called also mortality rate. Historic example of death rates (per 100,000) for leading causes of death for men aged 25â44 years.