Earth Day is this Sunday. Time to start talking about better family planning for everyone.

Nicholas Kristof, writing for the New York Times, recently examined where humans’ and animals’ interest seem to collide, but eventually flow into alignment. But he missed the biggest confluence of all, the significant drop in average fertility rates around the world. Smaller families have allowed more investment in and development of each child, a pronounced period economic growth, and perhaps our best chance to stave off the worst effects of climate change and the many related environmental catastrophes.

Recent studies show that air pollution contributed to the deaths of six million people in 2016 alone. The number of deaths would have been reduced if world leaders had done a better job on family planning, had used modeling that reduced overall emissions and consumption, and at the same time had invested more in each person from the start, to make them more resilient. Inaction on family planning helped cause these deaths. When will that change? When will the United Nations Secretary General, for example, take the action we need?

Smaller families that invest more in each child are the beginning of, and central to, any version of an environmental and animal protection ethic. Better family planning is a fair and win-win balance between what we need and animals need, between the human and nonhuman worlds. Better family planning helps humans and animals at the same time – more so than any of Kristof’s examples.

For Earth Day, speak up and take action for better family planning now.