How Do Recent Population Trends Matter To Climate Change?

by Leiwen Jiang and Karen Hardee

Summary

Strong evidence exists showing that demographic change is closely associated with greenhouse gas emissions, and that population dynamics will play a key role in attempts to mitigate and adapt to the effects of changes in the climate system in the future. It is clear that analyzing the compositional change of populations, specifically the age composition, the distribution of people in urban and rural areas, and household size and composition, is very important for understanding future needs and potential for mitigating carbon emissions and climate change. The analysis presented in this paper shows that by including only population size as the demographic variable in climate models, the contribution of “population” to climate change has been underestimated.

Similarly, understanding demographic trends, including fertility, population growth, urbanization, migration from environmentally depleted areas, and growing population density in marginal and vulnerable areas, is also crucial for the world to adapt to and cope with the adverse impacts of current and projected climate change.

Sir Nicholas Stern (2006) states that climate change threatens to cause the greatest and widest ranging market failure ever seen. He warns that one percent of global GDP must be invested in order to mitigate climate change, and that failure to do so could risk a recession worth up to 20 percent of global GDP. Moreover, the adverse effects of climate change cannot be bound within any administrative boundaries. Climate change poses a grave challenge for the whole world and has wide ranging implications for human well-being as well as for security (Campell 2007; Military Advisory Board 2007), including the risk of armed conflict over resources and large-scale migrations of population within nations and across national borders. The IPCC estimates that 150 million environmental refugees will exist in 2050, due mainly to the effects of coastal flooding, shoreline erosion and agricultural disruption (McCarthy et al. 2001).

A range of development policies are urgently needed to address this situation, including renewed commitment to meeting the globally agreed Millennium Development Goals (MDGs). Investments in family planning and reproductive health, girls education, economic opportunities and empowering of women, and in youth could help least developed and developing countries to speed up their demographic transition, enabling them to achieve demographic windows of opportunity which may contribute to economic growth and a greater capacity to cope with climate change impacts. Population dynamics should not continue to be ignored in climate change adaptation strategies, and effective measures must meet the needs of the world’s most vulnerable citizens, including the needs of women.

Combating climate change calls for the spirit of environmental stewardship and international cooperation on a range of emissions reduction and adaptation approaches. These approaches will benefit from greater attention to population dynamics, including growth, household structure, urbanization and aging. Population policies and programs that promote universal access to voluntary contraception, when linked with broader efforts to address a range of demographic factors and meet development and poverty reduction objectives, such as the MDGs, will help lead to a more sustainable demographic future that will play a crucial role in climate change mitigation and adaptation.