BRISTOL: Whether residents of high-income countries are morally obliged to have fewer children is a growing debate in climate ethics. Due to the high anticipated carbon impact of future population growth, some climate ethicists express support for non-coercive population engineering policies such as reduced child tax credits.
This debate has attracted widespread public attention, making family planning a key issue in climate change prevention.
Much of the debate is underpinned by one influential US study published in 2009 from Oregon State University. The premise of the study is that a person is responsible for the carbon emissions of their descendants, weighted by their relatedness. A grandparent is responsible for one quarter of each of their grandchildren’s emissions, and so on.
By having a child, a cycle of continued procreation over many generations is started. The emissions of future generations are included in the carbon legacy of their ancestors.
THE CARBON IMPACT OF CHILDREN
Based on this logic, the authors found that having one child adds 9,441 tonnes of carbon dioxide to the carbon legacy of each parent. This equates to more than five times their own lifetime carbon emissions. The potential savings from reduced reproduction are therefore dramatic.
This result is usually taken at face value in both academic debates and popular discussions, while its details and assumptions are rarely scrutinised. Yet the result is contingent on the assumption that all future generations will indefinitely emit at 2005 levels, an assumption that now appears to be wide of the mark.
For example, from 2005 to 2019, before they were artificially suppressed by the COVID-19 pandemic, US per-capita emissions fell by 21 per cent. And they are likely to fall further in the future.
Large public investments are accelerating the transition towards carbon neutrality. The recent US Inflation Reduction Act allocated US$369 billion towards fighting climate change.