Historically the size of human communities has depended on their ability to harness resources. Population growth was relatively slow until the 18th Century, when a step-change in agricultural productivity helped world population to rise dramatically.
The industrial revolution initiated a huge increase in global trade while public health improved tremendously both changes enabled population to increase.
Later, in the mid 20th Century, increased agricultural productivity achieved through the Green Revolution allowed population numbers to double between 1950 and 1990. Nevertheless, our dependence on natural resources remains absolute. Numbers are now projected to rise from seven billion in 2010 to between eight and eleven billion by 2050. It is unlikely that an equivalent increase in food production can be repeated without the use of significantly more energy, water and fertiliser, inputs which are themselves limited and may also be vulnerable to climate change.
Industrialisation and rising standards of living are also increasing each person's consumption of water, energy and materials as well as food, and putting already limited space and amenities under yet more pressure. Our lifestyles and the technology we use are driving overconsumption, leading to serious consequences as resources run low.