The average life expectancy is the expected number of years a person born in a specific year is expected to live, based on current mortality rates. According to the World Health Organization, the global average life expectancy at birth was 72 years in 2016.

There are several factors that can contribute to a decrease in life expectancy, including:

Non-communicable diseases: Diseases such as cancer, heart disease, and diabetes are becoming more common worldwide and can shorten life expectancy.

Lifestyle factors: Unhealthy behaviors such as tobacco use, excessive alcohol consumption, and poor diet and exercise habits can contribute to chronic diseases and a shorter life span.

Environmental factors: Exposure to air pollution, unsafe drinking water, and other environmental hazards can also contribute to poor health and a shorter life expectancy.

Infectious diseases: Outbreaks of infectious diseases such as COVID-19, Ebola, and Zika can have a significant impact on life expectancy, particularly in developing countries with weaker health systems.

Socioeconomic factors: Income inequality, lack of access to quality healthcare, and other social determinants of health can also contribute to disparities in life expectancy between different groups of people.

It’s important to note that life expectancy can vary widely depending on factors such as geographic location, income level, and other demographic factors. While the global average life expectancy has been increasing over time, there are many areas of the world where life expectancy is much lower than the global average