In 2007 the world finally woke up to climate change. It has not, however, woken up to one of its fundamental causes – human population growth.

Introduction Climate change is the long-term alteration of weather patterns affecting our planet. In the modern world this occurs largely due to human produced greenhouse gases, such as carbon dioxide and methane, which trap heat in the atmosphere and alter the earth’s climate.

Human population both affects and is affected by climate change. Changes in population size have implications for the ability of societies to adapt to the effects of climate change and for the patterns of consumption and production that generate the emissions driving climate change.

Societies age when the age distribution of their population shifts towards an older age. This is a consequence of increasing longevity and falling birth rates.1

In recent years, governments across the world have been accepting more legal human rights obligations to combat gender inequalities. Despite this, discrimination against women is still widespread, and the severest of human rights violations are persisting in many countries.

A sustainable activity is one that is capable of going on for an indefinite period of time. Unfortunately, the term sustainable has been widely abused, as illustrated by the commonly-used contradiction sustainable growth: growth can never be truly sustainable in a finite world.

There are more people in the world than ever before, and we are living closer together, with over half the world’s population now in towns and cities.

Data from 2015 showed that, although extreme poverty had declined significantly over the past two decades, 14 per cent of the population of the developing world was still subsisting on less than $1.25 per day, defined by the UN as an international indicator of poverty. 

The greatest long-term personal contribution that most people can make to sustainability is to refrain from having an unsustainable number of children — as explained in our smaller families webpage.

Background We live in an Age of Migration, with 244 million people, or 3.3 per cent of the world’s population, living outside their country of birth in 2015. 1 Migration, as such, is not new. Studies by paleoanthropologists suggest that, since the earliest times for which we have evidence, our human ancestors and other hominids have migrated. More recently, many significant migrations have been recorded — for example, between 1836 and 1914 more than 30 million.