Tuesday, according to the United Nations, was eight billion day, i.e. the world’s population was projected to reach eight billion souls on November 15th.

Even if you like people, and my views on that are mixed, that’s a hell of a lot. In fact, it’s too many. And that’s not my opinion. It’s Planet Earth’s opinion. It can barely cope with the current multitudes. It can’t keep feeding, clothing and sheltering more and more. At least not unless we become a very great deal more modest in our demands. As Ghandi said “The world has enough for everyone’s need, but not enough for everyone’s greed.”

Our greedy species is taking up more than our fair share of space. Of the biomass of mammals on the planet, we now make up one-third. Our livestock take up most of the rest. The biomass of wild mammals, many of which our greed is driving into extinction, now make up around four percent.

How many of us can the planet sustain? According to the Australian Academy of Science, the estimates of Earth’s carrying capacity cover a broad range but the majority suggest eight billion or less. In other words we’re about at our limit.

This unprecedented growth of population—doubling in the last 50 years—is due largely to the increase in human lifespan from improvements in public health, nutrition, personal hygiene and medicine. It has also resulted from high levels of fertility in some countries.

But that’s the bad news. There is also good news.

It took the global population 12 years to grow from 7 to 8 billion, but it will take about 15 years to reach 9 billion. In other words, the growth rate is slowing down. According to Darrell Bricker, CEO at Ipsos Public Affairs and a fellow at the University of Toronto’s Munk School, “This is the last time we’re probably going to have a conversation about reaching another billion marker.”

Due mainly to contraception, followed by education and women’s rights, birthrates are falling almost everywhere. China is recording its lowest birth rate in history. India’s has dropped below replacement rate. That’s thirty-six per cent of the entire global population that are not at replacement level birth rates.

The UN predicts world population will reach 10.4 billion in the 2080s and remain at that level until 2100. Darrell Bricker is more optimistic. He predicts it will max out at “somewhere between eight and nine billion.” Patrick Gerland, chief of the UN’s population estimates and projections section, agrees the UN number is more of an upper range.

At the same time, life expectancy continues to get longer. In 2019, it reached 72.8 years globally, an increase of nearly nine years since 1990. The UN expects it to rise to roughly 77.2 years in 2050. We are going to be a planet of geezers.

Nonetheless, the Earth will heave a sigh of relief. It may be able to live with us after all. At least if we ultimately recognize that the planet and its resources are finite and curb our appetites accordingly.