If the number of children is not growing, why is the population still increasing

If there were few women in the reproductive age bracket the number of births will be low even when the fertility rate is high. This is what demographers refer to as ‘population momentum’ and it explains why the number of children in the world will not decline as rapidly as the fertility rate. The second chart in the panel below shows that the population growth over the last decades resulted in increasingly larger cohorts of women in the reproductive age bracket.

Source: ourworldindata.org