Society: Issues: Environment: Population topics focus on the negative or positive impact of population increase or decrease within an ecosystem, governmental region, or on a global scale. Population growth can be a positive or negative effect on an area, depending on pre-existing conditions in an area. For example, in rural areas in the US, a population growth might be welcome. On the otherhand, in crowded cities such as Tokyo, a large population growth might add complications in the cost of housing, unemployment rates, and car pollution. There are many causes of population increase such as longer lifespans due to advanced healthcare, better diets, increased agricultural production. On the otherhand, some causes of population decrease for a region might be lack of medicines, poor diets, and reduced agriculture production due to weather, insect swarms, and not rotating crops.