Editor's note: This column is the second part of an ongoing series that explores China's demographic challenges. As discussed in the first part of this series , dropping birth rates are driving China's demographic decline. But its population's rapid aging (and Beijing's failure to timely adjust the country's pension and retirement systems accordingly) presents an additional acute compounding challenge. China's life expectancy is now 78 according to the World Bank, the oldest in the country's recorded history. This is still low compared with developed countries, where the life expectancies range between 82 and 85 years old. But it is nonetheless a dramatic, society-altering improvement from the early 1960s, when people in China on average died before they were 45 years old.