Populations in Transition

2. The balance between incoming short-wave radiation and outgoing short-wave and long-wave radiation (6,7)
4. Population policy that encourages families to have more children (11,5)
8. Changes in a system that occur and lead to other changes, but eventually the whole system stabilises (8,8)
14. The movement of a population away from one part of a country to another. It occurs when people choose to move (9,8,9)
15. The average number of years to be lived by a group of people born in the same year in the same country (9,4)
16. A measure of non-workers divided by the workers. It compares the number of dependents and economically active members of society (10,5)
18. The location of people within an area (10,12)
19. Population policy that encourages families to have fewer children (12,5)

1. The benefits that come from a very large population of the population being in the adult age range, and a reduced proportion of young and /or elderly (11,8)
3. Number of people living in a given area, expressed as people per square kilometre (10,7)
5. The increasing amount of greenhouse gases in the atmosphere, as a result of human activities and their impact on atmospheric systems (8,10,6)
6. The ratio of males to females in a population (3,5)
7. The growth in a population as a result of birth rates exceeding death rates (7,8)
9. aka natural greenhouse effect, this is where certain gases allow short-wave radiation from the sun to pass through the atmosphere but trap some. This allows warming of the atmosphere (10,6)
10. A situation where the birth rate decreases and the number of elderly people increases (6,10)
11. Changes in a system that lead to greater deviation from the original condition (8,8)
12. The increase in temperatures around the world that has been noticed since the 1960s (6,7)
13. A city with more than 10 million people living in it
17. Migration that occurs due to war, persecution, famine, slavery, politics or natural disasters creating refugees and internally displaced people (6,9)