 In the medium variant, global fertility is projected to decline further to 2.2 in 2045 to 2050 and to 1.9 in 2095–2100.If the mortality rate is relatively high and the resulting life expectancy is therefore relatively low, changes in mortality can have a material impact on population growth.Where the mortality rate is low and life expectancy has therefore risen, a change in  mortality will have much less an effect.