Differences between Nigeria and Australia are large due to the lack of education. This leads to Nigeria having 3x the amount of births compared to Australia because they are not the use of contraception.
Reasons for variations in human wellbeing.
Another reason Nigeria faces the variation is the government corruption which affects the country as a whole. Corruption including the discovery of oil and selling overseas, which directly affects the economy and consequently other issues for their human wellbeing.
Consequences of this spatial variation of human wellbeing.
As Nigeria suffers from the drastically different fertility, mortality and life expectancy, the population continues to grow at an exponential rate. If this continues, the poverty rate is increased and the gap between the poor and wealthy is stretched further.
By having over half of Nigeria's population in poverty, they are unable to receive medical attention and aid. This causes the low life expectancy and high infant mortality rates which contrast to Australia's lower poverty rate and overall better human wellbeing.