“Hard limits” to population growth are things like food, water, energy, technology, living space, other basic needs and economic factors which limit people’s ability to access these things.
“Soft limits” to population growth are things like education, birth control, the desire for a better life individually and a better global future for humanity, religious celibacy or chastity or abstinence, female empowerment and economic participation, the suffering already caused by overpopulation and the desire to avoid further suffering, malnutrition or non-lethal starvation which reduces sexual libido, pollution and other man made causes of involuntary sterility or low sperm count or low fertility, desire to save the environment, aversion to pain and suffering when understood that population growth causes both.
Countries with better quality of life and access to food and basic needs often have lower birth rates and lower population growth. This shows that soft limits can actually be more effective than hard limits to stop population growth. You have plenty of countries in Africa running into hard limits and having some of the highest fertility and population growth rates at the same time. They also suffer massive problems like war, poverty, disease and low standard of living. This goes to show that running into the hard limits will pretty much let things get as bad as they can get before it stops population growth. The hard limits won’t stop all the suffering caused by overpopulation but will make enough people suffer TO DEATH that the population doesn’t grow. People fear pain, thus the soft limits are more effective when they understand that population growth was responsible for pain or suffering and avoid it.
