Our Climate Crisis and Family Planning

February 25, 2020 | FEE Content, FEE Posts


by Bob Leonard


Population and our climate crisis are directly linked. Every additional person increases carbon emissions (the rich more than the poor) and increases the number of climate change victims (the poor more than the rich).


Currently the net daily increase in human population, after subtracting deaths from births, is 220,000 people, or over 150 people every minute (395,000 births a day minus 175,000 deaths).


That equals over 80 million more people every year. That is 220,000 new dependent passengers on Spaceship Earth every day, all of whom will generate demand for resources and will cause GHG emissions.  


The personal decision of whether to have children or not touches on religion, sense of self, upbringing and long-held beliefs. Those beliefs are of questionable value and relevance in the 21st century. These legacy viewpoints are why population has not become the primary topic of discussion relative to our climate crisis. Climate scientists and activists may see the world through these beliefs. 


To state it upfront: the decision to have a child is the single most environmentally impactful decision any of us can make in our lifetimes. Having one fewer child will save 58.6 tonnes of CO2 per year. Here is a chart to put this in perspective:


Source: Wynes & Nicholas, Environmental Research Letters


The figure was calculated by totting up the emissions of the child and the child’s descendants, then dividing this total by the parent’s lifespan. Each parent was ascribed 50% of the child’s emissions, 25% of their grandchild’s emissions and 12.5% for their great grandchild. In other words, the amount of my genetic material in the child is 50%, the amount that’s in my grandchild is 25%, and the amount that’s in my great grandchild is 12.5%. Divided by the parent’s lifespan. So, say the average age of the parent when the child is born is 25, and average life span is 75, so divide by 50 years.


If an exceedingly committed environmentalist lived a life where she did all of the 10 satellite actions in the above chart, it would result in a savings of 8.52 tons per year. There are few people in either the developed or undeveloped countries that can do all of these. For each baby born there would have to be seven people completely committed to living a green lifestyle to offset the decision to have one child.


Population Numbers


Here is a chart that shows the ever smaller amount of time between attaining another billion of global population:



It’s clear that in the second half of the 20th century, the years between billion markers shortened noticeably. The first time interval was 32 years, the next 15 and then 12. The timespan from the 1970s to now is when CO2 PPMs, surface Earth temperatures, and resource depletion all accelerated dramatically. Population growth is a major cause.


To keep a population at a constant number, the replacement rate requires an average birth rate of 2.1 children per woman. Above this number the total population increases. Below 2.1 it decreases. In many parts of the world birth rates are slowing. The developed countries are mostly under this 2.1 number and countries in Africa and Asia are mostly above.


Project Drawdown, perhaps the most comprehensive study ever conducted on the lowering of GHG emissions, concluded that empowering and educating women is the single most effective way to reduce emissions. Drawdown’s number six solution is educating girls and number seven is family planning. Added together they become the number one solution. So it is a major component of moving to a Finite Earth Economy: to empower women and to provide them with what they need to live better and more productive lives.


Organized religions encourage large families to create increasing numbers of followers. The history of religion is to expand toward ever more believers. This was to ensure the survival of the religion’s dogma and to support its clergy. There is no major traditional religion that embraces birth control.


This is an area where the metaphor of Earth as a spaceship is especially relevant. Spaceships have finite resources. These resources must sustain the number of crew members onboard. The crew must make do with what is onboard. If the crew had many children, there would be a strain on the spaceship’s finite resources.


Social Pressures and Changing Views


Legacy thinking that couples should have children remained the norm until recently. Governments and corporations needed population growth to help sustain GDP growth. Religions needed to keep generating demand for their services. Most adults had grown up with one or more siblings, which therefore set expectations for their own procreation.  


In the 1980s there was a social phenomenon called DINK (Double Income, No Kids). With the economy exploding, husbands and wives had the opportunity to work to generate income and wealth. Many couples chose not to have children. These couples had to swim upstream against the perceptions of societal norms. Couples with children often accused the DINK couples of being selfish and indulgent.


Today, with a growing awareness of our climate crisis, many couples are choosing to have only one child, or none at all, or to adopt. 38% of 18- to 29-year-old Americans believe that a couple should consider the risks of climate change before deciding to have kids. “I can’t have a child unless I am seriously, seriously convinced that we are on a different path.”


Today we are just short of eight billion people on Earth. The UN and other organizations routinely project continued population growth resulting in something like 12 billion by 2100. I don’t believe it. Either we are going to change, globally, to having fewer than 2.1 children per woman, or nature is going to reduce our population via the effects of our climate crisis.





share your thoughts


Share the Site