The most comprehensive analysis of climate change solutions to date was arguably published just recently in a book named Drawdown. The possible solutions were ranked in terms of their ability to sequester atmospheric carbon dioxide, and in terms of how much money the schemes would save by 2050.
The top 10 solutions, like this study, also feature a plant-rich diet (#4 out of 100) and family planning (#7). However, air travel comes in at #43, and mass transit comes in at #37. Electric cars make an appearance at #26.
The slight discrepancies are partly due to this book’s focus on both individual action and that of a larger collective, like a state or national government.
In any case, it’s hard to argue that having fewer children – or, alternatively, giving women more access to contraceptives – is not an effective action individuals can take to combat climate change. This is perhaps most important in countries with high birth rates, which today tend to be developing nations.
By investing more in the education (and empowerment) of women, and making sure access to contraception is guaranteed for all demographics, the world could save a whopping 120 billion tons of CO2 by 2050 – more than any other method to push back against climate change, by far.