Human Fertility: Crisis, Which Crisis?

Somewhat contrary news items. An article in Human Reproduction Update re-raises the spectre of a human fertility crisis. Between 1973 and 2018, there was a decline in the average sperm count of circa 50%. This occurred in 53 countries, distributed across the entire globe (https://www.theguardian.com/society/2022/nov/15/humans-could-face-reproductive-crisis-as-sperm-count-declines-study-finds). On the same day, the United Nations decided the world's human population had reached 8 billion (https://www.nytimes.com/2022/11/15/world/world-population-8-billion.html). It also seems likely that the human population will reach 9 billion, mainly driven by birth rates in 6 African countries. In spite of declining sperm counts, human fertility seems to be in relatively rude health. Populations are falling in some countries largely, it seems, as consequences of human choice rather than declining fertility. In actuality, the greater the world's human population, the less likely we will be to effectively counter both catastrophic climate change and biodiversity loss.