The main reason for overpopulation is those in poverty or living in impoverished countries. These people don't have access to educational resources and lack proper sexual education. Women also don't have the easiest access to contraceptives. Thus making the number of unplanned pregnancies skyrocket. A better sex education can hep to reduce the abnormal amount of pregnancies occurring in under-developed countries. Which is where a majority of unplanned pregnancies happen.
The world population isn't slowing down anytime soon. In fact it's doing the exact opposite. The fastest growing countries are experiencing a lower life expectancy. Not only that, but the number of endangered species has also spiked. And if that wasn't bad enough with an increased population comes elevated crime rate. People are living shorter and shorter lives, so are certain species. The elevated crime rate is due to the competition for already limited resources. soon there won't be enough space or resources for everyone on Earth.
The earth's population is increasing at a rate that the planet just can't keep up with. Every year the population increases by eighty one million people. This puts people in closer proximity with each other. Which allows for emergence of new pandemics and epidemics. Diseases would also be able to spread very rapidly from person to person.
Overpopulation is and will cause unprecedented environmental damage, that we may not be able to solve in the future. as the population increases so does the amount of CO2 emissions. Rising conflicts between territories can be expected over ownership of land. The higher levels of CO2 will speed up climate change. And space for people to live and settle will disappear over time.
How many people can the earth support? No one is really sure, not even scientists. There are many factors that we have to consider. For example the limited availability of freshwater, a mere 1%. In addition, the many restrictions there are on the amount of food we are able to produce, factors in as well. Scientists predict that 10 billion people is the limit as far as food is concerned. Earth can't contain such an abundant amount of people and fulfill their wants and needs. The population needs to slow down if we want to keep necessities like food and water.