premise: The worlds population is expected to increase to more than 10 billion by 2050. Having a child in the developed world has a greater environmental impact than having a child in the developing world. Likewise having a large family in the developed world has a far greater environmental impact than having a large family in the developing world. This is because a child born into the developed world is much more likely to go on to have a high carbon dioxide emission lifestyle given that they are more likely to take regular flights, drive cars, live in a large energy-hungry home and so on. This has led some campaigners to argue that families in the developed world should think far more seriously about the environmental consequences of having children and should elect or be encouraged to have fewer.
hypothesis: If families living in the developing world were to have fewer children then they too would make a major cut in their families future carbon dioxide output.