The total world population according to 2021 is 7.9 billion.

Factors contributing to the world population growth:

1. Advancements in medicine and healthcare: With the discovery of vaccines and advancements in medical treatments, the number of deaths due to illnesses and disease has decreased, leading to an increase in the world population.

2. Increase in life expectancy: People are living longer than ever before due to better healthcare and medical treatments, which has led to an increase in the world population.

3. Fertility rates: Fertility rates have been high in many parts of the world, leading to an increase in the number of births and subsequently the world population.

4. Immigration: People moving from one country to another has also contributed to the world population growth.

Effects of the world population growth:

1. Strain on resources: As the population grows, there is an increased demand for resources such as food, water, and energy, which can lead to shortages and price increases.

2. Environmental impact: With more people on the planet, there is an increase in pollution, deforestation, and other environmental issues.

3. Urbanization: As people move to cities, there can be overcrowding and strain on infrastructure.

4. Globalization: The growth in population has contributed to the globalization of the economy, culture, and politics.

Conclusion:

The world population is constantly growing, and it is important to consider the effects of this growth on the planet and its resources. Sustainable development and responsible resource management are important to ensure a better future for all.

7.9 is the total population of the world in 2021.